担当区分：筆頭著者,　責任著者   記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ijregi.2023.12.006

researchmap

担当区分：筆頭著者,　責任著者   記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Methicillin-resistant Staphylococcus aureus (MRSA) is a major infectious disease pathogen, and its molecular epidemiological profile has been changing. In this study, a total of 279 MRSA isolates were collected from patients with bloodstream infection (BSI) in Hokkaido, northern main island of Japan, for a 2-year period from August 2019 to July 2021. CC5 (ST5/ST764)-MRSA-IIa (SCCmec-IIa) (47%, n = 132) and CC1 (ST1/ST2725/ST2764)-MRSA-IVa (42%, n = 116) were found to be major lineages, with CC8-MRSA-IVa being lower prevalence (5%, n = 13). CC1-MRSA-IVa showed a relatively increased proportion compared with our previous study (22%, 2017-2019). Seven isolates with SCCmec IVa (2.5%) were positive for Panton-Valentine leukocidin genes on ΦSa2usa and belonged to ST8/spa-t008/agr-I/coa-IIIa, showing genetic features of the USA300 clone. Among these isolates, six isolates harbored arginine catabolic mobile element (ACME) type I typical to the USA300 clone, while it was not detected in an isolate (strain R3-8). Whole genomic analysis of strain R3-8 revealed that its chromosome was highly similar to the USA300 strain TCH1516, but lacked ACME, carrying a plasmid genetically close to that of USA300 strains. The present study revealed increasing trend of CC1-MRSA-IV and occurrence of a novel variant of the USA300 clone among MRSA from BSI in northern Japan.

DOI： 10.1089/mdr.2023.0203

PubMed

researchmap

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jmii.2023.07.004

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jgar.2023.08.009

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jac/dkad146

PubMed

researchmap

掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

Enterococcus faecalis and E. faecium are the major pathogens causing community- and healthcare-associated infections, with an ability to acquire resistance to multiple antimicrobials. The present study was conducted to determine the prevalence of virulence factors, drug resistance and its genetic determinants, and clonal lineages of E. faecalis and E. faecium clinical isolates in northern Japan. A total of 480 (426 E. faecalis and 54 E. faecium) isolates collected over a four-month period were analyzed. Three virulence factors promoting bacterial colonization (asa1, efaA, and ace) were more prevalent among E. faecalis (46–59%) than E. faecium, while a similar prevalence of enterococcal surface protein gene (esp) was found in these species. Between E. faecalis and E. faecium, an evident difference was noted for resistance to erythromycin, gentamicin, and levofloxacin and its responsible resistance determinants. Oxazolidinone resistance gene optrA and phenicol exporter gene fexA were identified in an isolate of E. faecalis belonging to ST480 and revealed to be located on a cluster similar to those of isolates reported in other Asian countries. The E. faecalis isolates analyzed were differentiated into 12 STs, among which ST179 and ST16 of clonal complex (CC) 16 were the major lineage. Nearly all the E. faecium isolates were assigned into CC17, which consisted of 10 different sequence types (STs), including a dominant ST17 containing multidrug resistant isolates and ST78 with isolates harboring the hyaluronidase gene (hyl). The present study revealed the genetic profiles of E. faecalis and E. faecium clinical isolates, with the first identification of optrA in ST480 E. faecalis in Japan.

DOI： 10.3390/antibiotics12010108

researchmap

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Objectives: This study aimed to elucidate the molecular characteristics and antimicrobial resistance of Streptococcus agalactiae (group B streptococcus, GBS) colonizing pregnant women in Japan. Methods: GBS isolates obtained from screening of pregnant women from 2017 to 2021 were analyzed for capsular serotype, sequence type (ST), and antimicrobial susceptibility. For levofloxacin-resistant isolates, mutations in the quinolone resistance-determining regions (QRDRs) of the gyrA, gyrB, and parC genes were analyzed. Results: Seventy-six GBS isolates were recovered from 1090 women (isolation rate: 7.0%). Of the 76 isolates, serotype III (31.6%) was the most prevalent, followed by V (19.7%), Ia (17.1%), and Ib (10.5%). Among the 22 STs identified, capsular serotype III/ST335-clonal complex (CC) 19 lineage was dominant (13.2%), followed by Ia/ST23, III/ST17, and V/ST1. Levofloxacin resistance was detected in 15.8% (n=12) of all the isolates, with serotype Ib being the most common. Most levofloxacin resistant isolates belonged to serotype Ib/CC10 or serotype V/CC19, with double mutations in the QRDRs, Ser81Leu in GyrA and Ser79Phe in ParC. Conclusions: The present study indicates the prevalence of the serotype III/ST335 (CC19) lineage, and the spread of serotype Ib/CC10 and serotype V/CC19 lineages, which are responsible for levofloxacin resistance in colonizing GBS in pregnant women in Japan.

DOI： 10.1016/j.ijregi.2022.07.002

PubMed

researchmap

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: Nonencapsulated Streptococcus pneumoniae (NESp) is emerging after the introduction of pneumococcal conjugate vaccines (PCVs). This study aimed to elucidate the genetic characteristics of penicillin-binding proteins (PBPs; PBP1a, 2b, and 2x) associated with penicillin nonsusceptibility in emergent NESp. METHODS: A total of 71 NESp isolates that were identified in our previous study during the PCV era in Japan (2011-2019) were analyzed for their amino acid sequences of transpeptidase domain in PBP 1a, 2b, and 2x. RESULTS: Overall, we identified 21 different PBP profiles (1a-2b-2x), all of which represent novel PBP profiles. The dominant PBP profiles were 13-16-ne1 (32.4%, n = 23), ne1-16-ne2 (14.1%, n = 10), and 13-7-ne4 (7.0%, n = 5) (novel PBP type was numbered with "ne" denoting "nonencapsulated"), accounting for 53.5% of all isolates. All isolates with the PBP profiles 13-16-ne1 and 13-7-ne4 and those having PBP1a type-13 and -131, PBP2b type-7, -ne1, and -ne2 showed nonsusceptibility to penicillin. A high degree of genetic diversity was found in PBP2x, with most of them (81.7%) being new types. CONCLUSIONS: Our current study identified the 21 novel PBP profiles and remarkable mutations in the PBPs, which may be potentially associated with penicillin nonsusceptibility in NESp.

DOI： 10.1016/j.ijid.2022.04.033

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/pathogens11040469

PubMed

Web of Science

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: Clostridium perfringens is a common anaerobic pathogen causing enteritis/enterocolitis and wound infections in humans. We analyzed clonal diversity and toxin gene prevalence in C. perfringens clinical isolates from humans in northern Japan. METHODS: Prevalence of nine toxin genes was analyzed for 585 C. perfringens isolates from patients collected for 20-month period between May 2019 and December 2020 by molecular methods. Sequence type (ST) based on multilocus sequence typing (Xiao's scheme) and alpha-toxin (PLC) sequence type were determined for a total of 124 isolates selected in the present study along with those in our previous study (2017-2018). RESULTS: Toxinotypes A (68.2%) was the most frequent, followed by F (31.6%), and G (0.2%), while additional toxin genes encoding binary enterotoxin (BEC/CPILE) and beta2 toxin were identified in one and six isolates, respectively. Among the 124 isolates with various toxin gene profiles, 62 STs including 53 novel types were identified, revealing the presence of six clonal complexes (CCs) consisting of 27 STs. Most of enterotoxin gene (cpe)-positive isolates belonged to CC36, CC41, and CC117. Based on 22 key amino acids in alpha toxin sequence, four PLC types (I-IV) including 21 subtypes were classified, and their relation to individual STs/CCs was clarified. Two isolates harboring bec/cpile belonged to different STs (ST95, ST131) and PLC types (If, IVb), indicating distribution of this toxin gene to distinct lineages. CONCLUSIONS: The present study revealed the diversity in C. perfringens clones of human origin with various toxin gene profiles represented by ST/CC and PLC type.

DOI： 10.1016/j.anaerobe.2021.102473

PubMed

researchmap

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: The emergence and spread of nonencapsulated Streptococcus pneumoniae (NESp) is a public health concern in the post-pneumococcal conjugate vaccine era. We analyzed the prevalence, molecular characteristics, and antimicrobial resistance of NESp responsible for noninvasive infections in northern Japan. METHODS: NESp isolates were identified using molecular and phenotypical methods among 4463 S. pneumoniae isolates from noninvasive infection cases during 4 study periods between January 2011 and January 2019. NESp isolates were analyzed for antimicrobial susceptibility, genotype, and virulence-associated genes. RESULTS: Seventy-one NESp isolates were identified (1.6% of total clinical isolates) and assigned to the null capsule clade (NCC)1 (pspK+) (94.4%) or NCC2 (aliC+/aliD+) (5.6%). The dominant sequence types (STs) were ST7502 (23.9%), ST4845 (19.7%), ST16214 (11.3%), ST11379 (9.9%), and ST7786 (7.0%). These 5 dominant STs and all 7 novel STs were related to the sporadic NESp lineage ST1106 or PMEN clone Denmark14-ST230. High non-susceptibility rates of NESp were observed for trimethoprim-sulfamethoxazole, erythromycin, and tetracycline (>92.9%), and multidrug resistance was observed in 88.7% of the NESp isolates, including all ST7502, ST4845, and ST11379 isolates. CONCLUSIONS: The study revealed that the dominant clonal groups of NESp were associated with a high prevalence of non-susceptibility to antimicrobials in northern Japan.

DOI： 10.1016/j.ijid.2021.02.109

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of bloodstream infections (BSIs). We aimed to study molecular epidemiological characteristics of MRSA isolates from BSIs in northern Japan to elucidate the recent trend of their clonal diversity. METHODS: MRSA isolates (n = 277) were collected from blood samples of patients who attended healthcare facilities in Hokkaido, the northern main island of Japan, for a two-year period from August 2017. Genotypes, virulence factors/drug-resistance determinants, and structure of SCCmec complex were analysed by PCR and sequencing analysis. RESULTS: SCCmec-IIa (n = 171, 61.7%) with coagulase genotype (coa-) II, ST5/ST764/ST2389 was the most common genetic trait, followed by SCCmec-IVa (n = 78, 28.2%), and IVl (n = 10, 3.6%). Among the MRSA-IVa, 14 isolates (5.1% of all the isolates) had genetic features identical to USA300 clone (ST8/coa-IIIa/spa-t008 having ΦSa2USA and ACME-I), while PVL/ACME-negative MRSA-IVa isolates (n = 64) were classified into coa-IIa/IIIa/VIIa/VIIb, with coa-VIIa/spa-t1784/ST1 being dominant. Other minor clones included ST8-SCCmec-I, and ST30/ST45/ST81/ST121/ST1232-SCCmec-V, among which the ST1232 isolate harboured PVL genes. Spermidine N-acetyltransferase gene (speG), which is typically present in ACME-I of USA300 clone, was also identified in two isolates, ACME-II'-positive ST764-MRSA-IIa and ACME-negative ST1-MRSA-IVa, showing resistance to spermine. speG of these isolates was located in additional SCCs adjacent to SCCmec. CONCLUSIONS: Our present study revealed clonal diversity of MRSA from BSIs in Japan, with increased prevalence of ST8-USA300. Distinct types of speG-carrying SCCs associated with SCCmec-II or IV were identified.

DOI： 10.1016/j.jgar.2020.12.008

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Staphylococcus argenteus, a novel staphylococcal species independent of S. aureus, causes a wide spectrum of infectious diseases. As detection of this species from humans and animals has been increasingly reported worldwide, its growing virulence and drug resistance via external genetic determinants has become concerning. In this study, the prevalence and genetic characteristics of virulence factors and drug resistance determinants were investigated for 82 S. argenteus clinical isolates in Hokkaido, Japan, for a one-year period starting in August 2019. These S. argenteus isolates corresponded to 0.66% of the total number of S. aureus isolates collected in the same period. The most prevalent genotype was sequence type (ST) 2250 and staphylocoagulase (coa) genotype XId (45.1%, n = 37), followed by ST1223-coa XV (30.5%, n = 25) and ST2198-coa XIV (24.4%, n = 20). Panton-Valentine leukocidin genes (lukS-PV-lukF-PV) were identified in a single ST2250 isolate. Only ST1223 isolates had the enterotoxin gene cluster (egc-2), seb, and selw (detection rate; 100%, 60%, and 84%, respectively), while sec, sey, sel26-sel27, tst-1 were only detected in ST2250 isolates (detection rate; 10.8%, 100%, 67.6%, and 10.8%, respectively). ST2198 isolates harbored selx at a significantly higher rate (60%) than isolates of other STs. Although most of S. argenteus isolates were susceptible to antimicrobials examined, ST2198 showed higher resistance rates to penicillin, macrolides, and aminoglycosides than other STs, and it harbored various resistance genes such as blaZ, erm(C), msr(A), lnuA, and aac(6')-Ie-aph(2″)-Ia. Only one ST2250 isolate possessed SCCmec-IVc, showing resistance to oxacillin. blaZ was the most prevalent determinant of resistance in the three STs and belonged to two plasmid groups and a chromosomal group, suggesting its diverse origin. lnu(A) in ST2198 isolates was assigned to a major cluster with various staphylococcal species. The present study indicates that the prevalence of virulence factors and drug resistance profile/determinants differ depending on the lineage (ST) of S. argenteus.

DOI： 10.3390/pathogens10020163

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Enterococcus faecalis is one of the major causes of urinary tract infection, showing acquired resistance to various classes of antimicrobials. The objective of this study was to determine the prevalence of drug resistance and its genetic determinants for E. faecalis clinical isolates in north-central Bangladesh. Among a total of 210 E. faecalis isolates, isolated from urine, the resistance rates to erythromycin, levofloxacin, and gentamicin (high level) were 85.2, 45.7, and 11.4%, respectively, while no isolates were resistant to ampicillin, vancomycin and teicoplanin. The most prevalent resistance gene was erm(B) (97%), and any of the four genes encoding aminoglycoside modifying enzyme (AME) were detected in 99 isolates (47%). The AME gene aac(6')-Ie-aph(2")-Ia was detected in 46 isolates (21.9%) and was diverse in terms of IS256-flanking patterns, which were associated with resistance level to gentamicin. Tetracycline resistance was ascribable to tet(M) (61%) and tet(L) (38%), and mutations in the quinolone resistance-determining region of both GyrA and ParC were identified in 44% of isolates. Five isolates (2.4%) exhibited non-susceptibility to linezolide (MIC, 4 μg/mL), and harbored the oxazolidinone resistance gene optrA, which was located in a novel genetic cluster containing the phenicol exporter gene fexA. The optrA-positive isolates belonged to ST59, ST902, and ST917 (CC59), while common lineages of other multiple drug-resistant isolates were ST6, ST28, CC16, and CC116. The present study first revealed the prevalence of drug resistance determinants of E. faecalis and their genetic profiles in Bangladesh.

DOI： 10.3390/microorganisms8081240

PubMed

researchmap

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Multidrug resistance (MDR) in non-vaccine serotypes (NVTs)-Streptococcus pneumoniae is a global public health concern after the widespread use of pneumococcal conjugate vaccines (PCVs). The present study aimed to analyze the prevalence of serotypes and antimicrobial susceptibilities of non-invasive/colonization isolates of S. pneumoniae eight years after the introduction of PCV in Japan. METHODS: A total of 545 non-invasive pneumococcal isolates (460 children, 85 adults) obtained from July 2018 to January 2019 were studied. All isolates were tested for susceptibility to ten antimicrobials and were characterized for serotypes, penicillin binding protein (PBP) genotypes, and macrolide resistance genes. RESULTS: Among children, 95.0% of isolates belonged to non-13-valent pneumococcal conjugate vaccine (PCV13) serotypes (NVTs), with 15A (15.0%) being dominant, followed by 35B (12.2%), 23A (11.1%), 15B (9.8%), and 15C (9.6%). In contrast, serotype 3 (18.8%) was the most prevalent in adults, while 15A, 10A, and 23A were also common. Serotypes covered by PCV13 and 23-valent pneumococcal polysaccharide vaccine (PPSV23) in all the adult isolates were 25.9% and 48.2%, respectively. High resistance rates were observed against erythromycin, tetracycline, and clindamycin (≥62.4% children, ≥58.8% adults). Penicillin-resistant and penicillin-intermediate isolates represented 2.2% and 33.8% of all isolates, respectively. Most isolates of the three dominant NVTs 15A, 35B, and 23A were non-susceptible to penicillin. Overall, multiple drug resistance (MDR) was detected in 69.0% of all isolates, including dominant NVTs 15A, 35B, 23A, 15B, and 15C. Among all the isolates, 81.8% harbored at least one altered PBP genes, and erm(B), mef(A/E) and both these genes were found in 68.2%, 23.3%, and 6.8%, respectively. High prevalence (>90%) of erm(B) was observed in serogroup 15, and serotypes 23A, 33F, and 12F. CONCLUSION: The present study revealed the high prevalence of NVTs 15 and 23A, and 35B showing MDR, suggesting their spread after introduction of routine PCV immunization.

DOI： 10.1016/j.jiph.2020.04.012

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Staphylococcal enterotoxins (SEs) are virulence factors of Staphylococcus aureus associated with various toxic diseases due to their emetic and superantigenic activities. Although at least 27 SE(-like) genes have been identified in S. aureus to date, the newly identified SE(-like) genes have not yet been well characterized by their epidemiological features. In this study, the prevalence and genetic diversity of SE gene sey and SE-like genes selw, selx, selz, sel26, and sel27 were investigated for 624 clinical isolates of community-acquired methicillin-resistant S. aureus (CA-MRSA). The most prevalent SE(-like) gene was selw (92.9%), followed by selx (85.6%), sey (35.4%) and selz (5.6%), while sel26 and sel27 were not detected. Phylogenetically, sey, selw, selx, and selz were discriminated into 7, 10, 16, and 9 subtypes (groups), respectively. Among these subtypes, sey was the most conserved and showed the highest sequence identity (>98.8%), followed by selz and selx. The SE-like gene selw was the most divergent, and four out of ten genetic groups contained pseudogenes that may encode truncated product. Individual subtypes of SE(-like) genes were generally found in isolates with specific genotypes/lineages of S. aureus. This study revealed the putative ubiquity of selw and selx and the prevalence of sey and selz in some specific lineages (e.g., ST121) in CA-MRSA, suggesting a potential role of these newly described SEs(-like) in pathogenicity.

DOI： 10.3390/toxins12050347

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Panton-Valentine leukocidin (PVL) is a pore-forming toxin encoded by genes on bacteriophages distributed to Staphylococcus aureus, associated with its increased virulence to humans. In this study, molecular epidemiological characteristics were investigated for 239 clinical isolates of S. aureus collected in a tertiary care hospital in Yangon, Myanmar, particularly with regard to methicillin resistance and PVL genes. Methicillin-resistant S. aureus (MRSA) accounted for 13.8% (33/239) and possessed mostly types IV- and V-SCCmec, while types III- and IX-SCCmec were identified in a few isolates. PVL genes were detected in 66.7% and 28.6% in MRSA and methicillin-susceptible S. aureus (MSSA), respectively. Among PVL-positive MRSA, ST772/SCCmec-V isolates (i.e., Bengal Bay clone) were predominant (73%, 16/22), and harbored PVL gene-encoding bacteriophage ΦSa119. Furthermore, two ST8-MRSA-SCCmec-IVa isolates harbored type-I arginine catabolic mobile element and ΦSa2usa: these isolates were considered the USA300 clone first identified in Myanmar. ΦPVL was the most frequent PVL phage among MSSA (56%, 33/59), and distributed to various genotypes, with ST88 and ST121 being dominant. In contrast, ΦSa2usa and ΦSa119 were also detected in MSSA with genotypes other than ST8 or ST772, suggesting the spread of these PVL phages to MSSA. The present study revealed potentially high prevalence of PVL phages among diverse clones of MRSA and MSSA in Myanmar.

DOI： 10.1089/mdr.2019.0208

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Staphylococcal cassette chromosome mec (SCCmec) elements are highly diverse and have been classified into 13 types. The arginine catabolic mobile element (ACME) is an SCC-like element harbouring an arginine deiminase pathway gene cluster (ACME-arc). ACME type I (ACME I), additionally including a spermidine/spermine-N1-acetyltransferase gene (speG), is considered to have contributed to the rapid spread of the most successful MRSA clone, USA300. OBJECTIVES: To characterize the SCC composite islands (SCC-CIs) in ST5 MRSA positive for both ACME-arc and speG. METHODS: Three ST5 MRSA strains (SC640, SC792 and SC955) collected in Hokkaido, Japan were subjected to WGS and the SCC-CIs were determined. RESULTS: The SCC-CIs consisted of four (SC640 and SC792) or three (SC955) SCC/SCC-like elements and commonly harboured both an ACME type II' and an SCC encoding speG. These SCC-CIs appear to mimic ACME I in USA300, in that they are equipped with ACME-arc and speG. The SCC-CIs of SC640 and SC792 contained novel SCCmec/SCCmec-like elements at the 3' end, whereas SC955 contained SCCmec type V. The SCCmec of SC792 carried mec complex A and ccrC1, which was determined to be novel and designated as SCCmec type XIV (5A). SC640 harboured an SCCmec-like element derived from SCCmec type XIV. It lacked most of the downstream region of the mec complex, including the left chromosomal attachment site (SCCmec XIV Δkdp/DR-L), and lost its capability for chromosomal excision, suggesting that the mecA gene is immobilized on the chromosome. CONCLUSIONS: These findings provide evidence for increasing complexity of SCC-CIs.

DOI： 10.1093/jac/dkz406

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Molecular epidemiological characteristics were investigated for 1,041 isolates of methicillin-resistant Staphylococcus aureus (MRSA) collected in a tertiary care hospital in northern Japan for a 4-year period (2011-2014). Genotypes (staphylococcal cassette chromosome mec [SCCmec], sequence type, spa, coa, etc.) and the presence of drug resistance/virulence factor genes in the isolates were analyzed by multiplex/uniplex PCR, and PCR-direct sequencing as needed. Among these MRSA, predominant SCCmec type was IIa (87.2%), followed by IV (10.1%) and V (1.2%). The SCCmec IIa-MRSA belonged to coagulase genotype (coa) IIa and ST5/ST764, which are known as major health care-associated-MRSA (HA-MRSA) in Japan (New York/Japan clone) and its variant. Panton-Valentine leucocidine (PVL) genes were detected in only five isolates (0.5%) with genotypes ST8-SCCmec IVa/spa-t008/coa-IIIa (USA300 clone), ST6-SCCmec IVb, and ST59-SCCmec V (Taiwanese clone). Arginine catabolic mobile element (ACME) type I and II' were identified in three and five isolates of ST8-SCCmec IVa and ST764-SCCmec IIa MRSA, respectively. PVL-/ACME- isolates were classified into various STs/clonal complexes (CCs), with CC1, CC5, CC8, CC89, and CC121 being common. It was notable that SCCmec IVl was the most common among SCCmec IV subtypes, and was carried by almost half of coa-IIIa isolates (47%, 34/72) without PVL genes, which represented the novel ST8 MRSA clone spreading in Japan (i.e., "ST8/CA-MRSA/J"). Uncommon MRSA clones in Japan, ST72-SCCmec IV (South Korean clone), ST398 livestock-associated clone, and ST20 bovine-associated MRSA, were identified. Furthermore, we isolated PVL-negative ST8-SCCmec I/coa-IIIa and ST81-SCCmec V/coa-VIIa MRSA, which were considered presumptive novel clones. The present study revealed the genetic diversity of HA-MRSA, including potentially emerging clones of putative different origins.

DOI： 10.1089/mdr.2018.0468

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Staphylococcus argenteus, a novel emerging species within Staphylococcus aureus complex (SAC), has been increasingly reported worldwide. In this study, prevalence of S. argenteus among human clinical isolates, and their clonal diversity and genetic characteristics of virulence factors were investigated in Hokkaido, the northern main island of Japan. During a four-month period starting from March 2019, twenty-four S. argenteus and 4330 S. aureus isolates were recovered from clinical specimens (the ratio of S. argenteus to S. aureus :0.0055). Half of S. argenteus isolates (n = 12) belonged to MLST sequence type (ST) 2250 and its single-locus variant, with staphylocoagulase genotype (coa-) XId, while the remaining isolates were assigned to ST2198/coa-XIV (n = 6), and ST1223 with a novel coa-XV identified in this study (n = 6). All the isolates were mecA-negative, and susceptible to all the antimicrobials tested, except for an ST2198 isolate with blaZ and an ST2250 isolate with tet(L) showing resistance to ampicillin and tetracyclines, respectively. Common virulence factors in the S. argenteus isolates were staphylococcal enterotoxin (-like) genes sey, selz, sel26, and sel27 in ST2250, selx in ST2198, and enterotoxin gene cluster (egc-1: seg-sei-sem-sen-seo) in ST1223 isolates, in addition to hemolysin genes (hla, hlb, and hld) distributed universally. Elastin binding protein gene (ebpS) and MSCRAMM family adhesin SdrE gene (sdrE) detected in all the isolates showed high sequence identity among them (> 97%), while relatively lower identity to those of S. aureus (78-92%). Phylogenetically, ebpS, sdrE, selx, sey, selw, sel26, and sel27 of S. argenteus formed clusters distinct from those of S. aureus, unlike sec, selz, tst-1, and staphylokinase gene (sak). The present study revealed the prevalence of S. argenteus among clinical isolates, and presence of three distinct S. argenteus clones (ST2250; ST2198 and ST1223) harboring different virulence factors in northern Japan. ST2198 S. argenteus, a minor clone (strain BN75-like) that had been rarely reported, was first identified in Japan as human isolates.

DOI： 10.3390/microorganisms7100389

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pneumococcal proteins unrelated to serotypes are considered to be candidates of antigens in next-generation vaccines. In the present study, the prevalence of vaccine candidate protein genes, along with serotypes and antimicrobial resistance determinants, was investigated in a total of 57 isolates obtained from a tertiary care hospital in Japan. All of the pediatric isolates and 76.6% of the adult isolates did not belong to PCV13 (a 13-valent pneumococcal conjugate vaccine) serotypes, and 70.2% of all isolates showed multidrug resistance. All of the isolates had ply, pavA, nanA, and nanB, and high prevalence was noted for the pspA and pspC genes (96.5% and 78.9%, respectively). Detection rates for the pneumococcal histidine triad protein (Pht) genes phtA, phtB, phtD, and phtE were 49.1%, 26.3%, 61.4%, and 100%, respectively. Two fusion-type genes, phtA/B and phtA/D, were identified, with a prevalence of 36.9% and 14.0%, respectively. These fusion types showed 78.1-90.0% nucleotide sequence identity with phtA, phtB, and phtD. The most prevalent pht profile was phtA + phtD + phtE (26.3%), followed by phtA/B + phtE (19.3%) and phtA/B + phtD + phtE (17.5%), while pht profiles including phtD and/or phtA/phtD were found in 71.9% of isolates. The present study revealed the presence of two fusion types of Pht and their unexpectedly high prevalence. These fusion types, as well as PhtA and PhtB, contained sequences similar to the B cell epitopes that have been previously reported for PhtD.

DOI： 10.3390/pathogens8040162

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Clostridium perfringens (C. perfringens) is responsible for food-borne gastroenteritis and other infectious diseases, and toxins produced by this bacterium play a key role in pathogenesis. Although various toxins have been described for C. perfringens isolates from humans and animals, prevalence of individual toxins among clinical isolates has not yet been well explored. In the present study, a total of 798 C. perfringens clinical isolates were investigated for prevalence of eight toxin genes and their genetic diversity by PCR, nucleotide sequencing, and phylogenetic analysis. Besides the alpha-toxin gene (plc) present in all the isolates, the most common toxin gene was cpe (enterotoxin) (34.2%), followed by cpb2 (beta2 toxin) (1.4%), netB (NetB) (0.3%), and bec/cpile (binary enterotoxin BEC/CPILE) (0.1%), while beta-, epsilon-, and iota-toxin genes were not detected. Genetic analysis of toxin genes indicated a high level of conservation of plc, cpe, and netB. In contrast, cpb2 was revealed to be considerably divergent, containing at least two lineages. Alpha-toxin among 46 isolates was classified into ten sequence types, among which common types were distinct from those reported for avian isolates. A single isolate with bec/cpile harbored a plc variant containing an insertion of 834-bp sequence, suggesting its putative origin from chickens.

DOI： 10.3390/toxins11060326

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pneumococcal isolates from adult patients in northern Japan in 2016 were subjected to molecular investigation related to pneumococcal surface protein A (PspA) and drug resistance determinants. Of the 51 isolates, serotype 3/ST180 was the most prevalent (17.6%), followed by 35B (ST2755/ST558) (11.8%) and 15A (ST63/ST7874/ST13068/ST13785) (9.8%). Coverage of serotypes by 13-valent conjugate vaccine and 23-valent polysaccharide vaccine was 27.5% and 49%, respectively. All the isolates expressed PspA family 1 or 2 (51% and 49%, respectively). Each serotype was associated with either of the PspA families (e.g., serotype 3, PspA family 1; serotypes 35B and 15A, PspA family 2). Multidrug resistance (MDR) was found in 84.3% of the isolates. Minimum of one altered penicillin-binding protein gene was detected in 82.4% of isolates, indicating 25.5% non-susceptibility to penicillin. Serotypes 15A and 35B were predominant and demonstrated MDR. An isolate of serotype 15A/ST13785 (single-locus variant of ST242) was resistant to fluoroquinolones associated with double mutation in the quinolone resistance-determining regions of gyrA and parC. The present study indicates the spread of MDR pneumococci represented by isolates of serotypes 3, 15A, and 35B, and prevalence of both PspA family 1 and 2 in isolates obtained from adult patients.

DOI： 10.1089/mdr.2018.0267

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Genetic background and molecular characteristics of Staphylococcus aureus collected from patients with skin and soft tissue infections were studied in the North-Central region of Bangladesh from 2015 to 2016. Among 430 clinical isolates, methicillin-resistant S. aureus (MRSA) accounted for 31% having SCCmec type IV (73%) and V (14%), and belonged mostly to coagulase (coa) genotypes IIa, IIIa, IVb, and XIa, while dominant coa type in methicillin-susceptible S. aureus (MSSA) was IIIa, followed by Va, IIa, and VIa. Panton-Valentine Leukocidin genes (pvl) were detected at higher rate in MSSA (54%) than in MRSA (24%). Based on multilocus sequence typing, pvl-positive MRSA isolates were classified into clonal complex 88 (CC88) (ST88, ST2884, ST4345), CC6 (ST6, ST4350), and CC1 (ST1, ST772), while pvl-negative MRSA into CC5, CC22, CC80, CC121, and CC672. The pvl-negative ST80 MRSA isolates had SCCmec-IVa (agr-III/coa-XIc, etd/edinB-positive, fusB-negative), indicating that they belong to the novel CC80 clade related to the European community-acquired MRSA clone. Among MSSA, genotypes ST121/spa-t645/coa-Va and ST2884 (CC88)/spa-t2393/coa-IIIa were identified in both pvl-positive and negative isolates, and all the ST772 isolates harbored pvl. All the ST121 isolates had a variant of elastin-binding protein gene (ebpS-v) with internal 180-nucleotide deletion. The present study suggested that CC88 (ST88, ST2884) and ST772 are the putative dominant lineages of pvl-positive MRSA/MSSA, while novel CC80 clade is one of the main pvl-negative MRSA lineages distributed endemically in Bangladesh.

DOI： 10.1089/mdr.2018.0123

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Staphylococcus argenteus is a novel emerging species of coagulase-positive staphylococcus that is genetically closely related to Staphylococcus aureus. To elucidate the molecular differences in the virulence factors (staphylocoagulase, protein A, alpha-haemolysin, enterotoxin-like toxin and staphylokinase) between these staphylococcal species, S. argenteus that had recently been isolated in Myanmar (five nasal isolates and four clinical isolates) were analysed. METHODOLOGY: The nucleotide sequences of the virulence factors were determined by PCR and direct sequencing, followed by phylogenetic analysis by mega6 and multiple alignment by clustalw using the published sequence data for S. aureus and S. argenteus. RESULTS: Six S. argenteus isolates belonged to MLST sequence type (ST) 2250, while others belonged to ST4625, ST2198 and ST2854. The novel staphylocoagulase (coa) genotype XIV and the novel coa-XI subtype (XId) were identified in an ST2198 isolate and all other isolates, respectively. Among the S. argenteus isolates, the protein A and alpha-haemolysin genes showed high sequence identity (96-98 % and >99 %, respectively), while lower identity was observed between S. argenteus and S. aureus (88-91 % and 86 %, respectively), with both species showing phylogenetically distinct clusters. Similar findings were found for the staphylococcal enterotoxin (SE)-like toxin genes selw, selx and sely. In contrast, the staphylokinase genes were almost identical between these two species. All of the coa-XId isolates had a CRISPR/Cas locus at the site of orfX without having SCCmec, whereas an ST2198 isolate lacked this locus. CONCLUSION: The primary virulence factors (staphylocoagulase, protein A andalpha-haemolysin) as well as the SE-like toxins of S. argenteus were genetically discriminated from those of S. aureus, revealing the presence of the novel coa-type/subtype (coa-IXd, XIV) in S. argenteus.

DOI： 10.1099/jmm.0.000869

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Spread of Gram-negative bacteria producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases constitutes a growing challenge in control of bacterial infections. In this study, prevalence and genetic characteristics of Escherichia coli and Klebsiella pneumoniae harboring ESBL and/or carbapenemase genes, with other beta-lactamase/resistance genes, were investigated for a total of 375 clinical isolates in Mymensingh located in north-central Bangladesh. The major ESBL gene was blaCTX-M-1 group, which was detected in 33.9% and 51.4% of E. coli and K. pneumoniae, respectively, with CTX-M-15 gene being dominant. SHV-type beta-lactamase genes, including newly identified alleles (SHV-201 and SHV-202) were detected at higher rate in K. pneumoniae (27%). Nine isolates of E. coli (3.9%) harbored carbapenemase genes; blaNDM-1 (phylogenetic group A-sequence type 2104 (A-ST2104), B2-ST73), blaNDM-5 (A-ST167, B2-ST38/ST2659-related STs), and blaNDM-7 (B1-ST101/ST224, D-ST6682). AmpC beta-lactamase genes (blaCMY-2 and blaCMY-42) were detected in E. coli, which mostly harbored blaCTX-M-15 and plasmid-mediated quinolone resistance (PMQR) determinants (aac6'-Ib-cr, qnrB, qnrS, qepA, and oqxAB). A new CMY allele (CMY-160) belonging to CMY-2 group was identified in phylogenetic group D E. coli. Among K. pneumoniae, carbapenemase gene was detected in three isolates (2%); blaNDM-1 in ST11 and ST1322, and blaOXA-181 in ST43 isolate. As well as higher rate of aac6'-Ib-cr in K. pneumoniae (39%), PMQR gene oqxAB was also commonly found among isolates analyzed. These findings indicated spread of blaNDM genes to diverse E. coli clones and emergence of blaOXA-181 in K. pneumoniae, with increased prevalence of ESBLs represented by CTX-M-15 in Bangladesh.

DOI： 10.1089/mdr.2018.0063

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The increasing trend of Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases is a global public health concern. In this study, prevalence and molecular characteristics of E. coli harboring ESBL and carbapenemase genes were investigated for 426 isolates derived from various clinical specimens in a teaching hospital in Yangon, Myanmar, for the 1-year period beginning January 2016. A total of 157 isolates (36.9%) were ESBL producers and harbored CTX-M-1 group genes (146 isolates; blaCTX-M-15, blaCTX-M55) or CTX-M-9 group genes (11 isolates; blaCTX-M-14, blaCTX-M-27). Carbapenem resistance was detected in 35 isolates (8.2%), among which 26 isolates had carbapenemase genes encoding NDM-1 (2 isolates), NDM-4 (6 isolates), NDM-5 (14 isolates), NDM-7 (3 isolates), and OXA-181 (2 isolates). blaNDM-5 was identified in phylogenetic groups A, B1, and D isolates belonging to various genotypes (ST101, ST354, ST405, ST410, ST1196) associated with blaTEM-1, blaCTX-M-15, blaOXA-181, blaCMY-2, blaCMY-6, blaCMY-42, qnrB, qnrS, or aac6'-Ib-cr. While two isolates with blaOXA-181 belonged to phylogenetic group A-ST410, one isolate had also blaNDM-5, as well as blaCTX-M-15 and blaCMY-2, and the other harbored blaCMY-42 and aac6'-Ib-cr, showing different resistance patterns. Phylogenetic group B2 isolates examined were classified into mostly ST131 and had solely blaCTX-M-15 or blaCTX-M-27, harboring more virulence factors than other phylogenetic groups. The present study revealed high prevalence of ESBL genes represented by blaCTX-M-15 and dominance of blaNDM-5 among NDM genes, disseminating to various E. coli clones. Notably, carbapenemase gene encoding OXA-181 was first identified in Myanmar, suggesting its spread together with NDM genes.

DOI： 10.1089/mdr.2017.0387

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Among the pneumococcal proteins, pneumococcal surface protein A (PspA) is considered the most promising candidate for a serotype-independent vaccine. This study aimed to investigate the serotype, genetic diversity of PspA, lineage (genotype) and drug resistance traits of pneumococcal isolates from paediatric patients. METHODOLOGY: A total of 678 non-invasive pneumococcal isolates obtained from June to November 2016 were analysed. All isolates were characterized for PspA families, serotypes and macrolide resistance genes. Seventy-one representative isolates of non-vaccine serotypes (NVTs) were genetically analysed for the clade-defining region (CDR) of PspA, as well as multi-locus sequence typing (MLST). RESULTS: The detection rate of NVTs was 87.9 % (n=596), including dominant NVTs 15A (14.5 %, n=98), 35B (11.8 %, n=80), 15C (9.3 %, n=63) and 23A (9.0 %, n=61). Most isolates (96.6 %) possessed macrolide resistance genes erm(B) and/or mef(A/E). PspA families 1, 2 and 3 were detected in 42.3, 56.6 and 0.6 % of isolates, respectively. Nucleotide sequences of CDR showed high identity (90-100 %) within the same PspA clade, although the CDR identity among different PspA families ranged from 53 to 69 %. All isolates of NVTs 23A, 10A, 34, 24, 22F/22A, 33F, 23B and 38 were from PspA family 1, while NVTs 35B, 15C, 15B and 11A/11D isolates were from family 2. In contrast, genetically distinct PspAs were found in NVTs 6C and 15A. PspA family 3/clade 6 was detected in only NVT serotype 37 isolates assigned to ST447 and ST7970, showing the mucoid phenotype. CONCLUSION: The present study revealed the predominance of PspA families 1 and 2 in NVTs, and the presence of family 3 in serotype 37.

DOI： 10.1099/jmm.0.000775

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

High-level fluoroquinolone resistance is conferred by the mutation of conserved serine and acidic amino acids in the quinolone resistance-determining region (QRDR) of the A subunits of the type II topoisomerases, DNA gyrase (GyrA) and topoisomerase IV (ParC). In Japan, fluoroquinolone-resistant Enterococcus faecium continues to emerge in clinical settings. We analyzed 131 Japanese E. faecium clinical isolates for susceptibility to levofloxacin (LVFX), and QRDR mutational status. The bacterial collection had a high percentage of resistance (79%) and showed elevated drug minimal inhibitory concentrations (MICs). Eighty-three isolates had single or combined mutations in gyrA and/or parC; all were resistant to LVFX. A strong correlation was evident between log-transformed MICs and the total number of QRDR mutations (r = 0.7899), confirming the involvement of QRDR mutations in drug resistance, as previously described. Three-dimensional modeling indicated that the amino acid change(s) in QRDR could disrupt the interaction between the enzymes and drugs: the most common cause of quinolone resistance. Interestingly, eight isolates had a single mutation on gyrA and exhibited significantly reduced susceptibility. These data imply that either DNA gyrase or topoisomerase IV can be the primary target of fluoroquinolones, although topoisomerase IV is commonly thought to be the primary target in gram-positive bacteria.

DOI： 10.1089/mdr.2016.0328

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2017.05.010

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Asymptomatic carriers of toxigenic Staphylococcus aureus are potential source of diseases, including food poisoning. Toxigenic potential and genetic traits of colonizing S. aureus were investigated for 563 healthy food handlers in Myanmar. Carriage of S. aureus was found in 110 individuals (19.5%), and a total of 144 S. aureus isolates were recovered from nasal cavities (110 isolates) and hands (34 isolates). Panton-Valentine leucocidin genes (pvl) were detected in 18 isolates (12.5%), among which 11 isolates were classified into coa-VIa, agr type III, and ST1930 (CC96) that had been also detected in pvl-positive clinical isolates in Myanmar. A pvl-positive, ST2250 nasal isolate was identified as S. argenteus, a novel coagulase-positive staphylococcus species. Toxic shock syndrome toxin-1 (TSST-1) gene was detected in five pvl-negative isolates. All of the 144 isolates harbored at least one of the 21 enterotoxin(-like) gene(s). The most prevalent enterotoxin(-like) gene was selw (98%), followed by selx (97%), sei (28%), sely (28%), sem (26%), sel (24%), and sea and sec (22% each). Considerable genetic diversity with five groups was detected for selw. The present study revealed the relatively high rate of pvl, as well as the wide distribution of enterotoxin(-like) genes among colonizing S. aureus in Myanmar.

DOI： 10.3390/toxins9080241

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Mary Ann Liebert Inc.  

DOI： 10.1089/mdr.2016.0176

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: In Japan, the 7-valent pneumococcal vaccine (PCV7) was introduced in 2010 and, in 2013, the PCV7 was replaced with the 13-valent pneumococcal vaccine (PCV13). This study was conducted to investigate serotypes, antimicrobial resistance and prevalence of pilus islets in pneumococcal isolates from inpatients in a Japanese tertiary hospital. METHODOLOGY: From April 2011 to February 2016, 151 isolates [95 (18 children, 77 adults) and 56 (19 children, 37 adults) in the PCV7 and PCV13 periods, respectively] were collected. All isolates were serotyped using genetic methods and were tested for susceptibility to 18 antimicrobials. Unaltered penicillin-binding protein (PBP) genes, macrolide resistance genes and pilus islets were identified by PCR. RESULTS: Between the two periods, the prevalence of non-PCV13 serotypes was shown to increase from 50.0 to 78.9 % in children, and serotype 3 increased from 14.3 to 24.3 % in adults. Six of seven isolates from invasive diseases were assigned to non-PCV13 serotypes. Overall, multidrug resistance (MDR) was detected in 46.4 % of isolates, which included the dominant non-PCV13 serotypes 6E, 15A and 23A (prevalence≥75.0 %). gPRSP (three altered genes pbp1a, pbp2b and pbp2x) and macrolide resistance genes [erm(B) and/or mef(A/E)] were detected in 35.8 and 93.4 % of all isolates, respectively. Pilus islets [PI-1 (clade I, II and III) and/or PI-2] were found in 22.5 % (34/151) of isolates belonging to six different serotypes (19F, 23F, 19A, 6E, 15B and 35B) and 88.2 % (30/34) of these exhibited MDR. CONCLUSION: This study revealed the spread of MDR in several non-PCV13 serotypes and in isolates with pilus islets.

DOI： 10.1099/jmm.0.000479

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2017.02.008

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Since the implementation of routine PCV13 immunization in Japan, nonvaccine serotypes (NVTs) have been increasing among clinical isolates of Streptococcus pneumoniae. In this study, susceptibility to 18 antibiotics was tested for all the 231 isolates with NVTs, which were collected from children <16 years of age in northern Japan in 2014 (July-November). High resistance rates were observed for macrolides (>90.9%), tetracycline (91.3%), and clindamycin (75.3%), while penicillin (PEN) nonsusceptibility (PNSP; MIC ≥0.12 μg/ml) was detected in 42.9% of the pneumococci [39.4%; PEN-intermediate S. pneumoniae (PISP), 3.5%; PEN-resistant S. pneumoniae (PRSP)]. All serotype 15A isolates were PRSP (MIC, ≥2 μg/ml) or PISP, and PNSP was prevalent in also serotypes 23A (96.9%), 6C (41%), and 35B (33.3%). Overall, 42.0% of the isolates showed multidrug resistance (MDR). Sequence types (STs) determined for 20 PNSP isolates with NVTs were ST63 (15A), STs 242 or 5832 (6C), STs 338 or 5242 (23A), and ST558 (35B). All the PNSP isolates possessed tet(M), and erm(B) or mefA(A/E), and 70% of them were gPRSP having three altered genes pbp1a, pbp2x, and pbp2b. Among alterations in transpeptidase-coding region of penicillin-binding proteins (PBPs), two substitutions of T371S in the STMK motif and TSQF574-577NTGY in PBP1a were common to all PRSP isolates. The present study showed the spread of PNSP in NVTs 15A, 23A, 6C, and 35B, and the emergence of the MDR international clone Sweden15A-ST63 in northern Japan.

DOI： 10.1089/mdr.2016.0054

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier B.V.  

DOI： 10.1016/j.meegid.2016.11.001

PubMed

researchmap

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Bangladesh is considered as a high-risk country for emerging infectious diseases because of its high population density, poverty, and unhygienic conditions. Although control efforts have primarily been focused on major infectious diseases such as diarrheal diseases, tuberculosis, malaria, and HIV infection, the prevalence and impact of many local or minor infectious diseases are still unclarified in this country. In this review, we present our recent experience and outcomes of collaborative research on puerperal infection (PI), which is a poorly defined infectious disease in Bangladesh. PI is the most common complication during the perinatal period in developing countries. We investigated the incidence of individual species of aerobic bacteria causing PIs and their drug resistance, and the genetic traits of isolates during the two-year period (2010-2012). The common species of isolates from patients with PIs were Escherichia coli, Enterococcus faecalis, Staphylococcus haemolyticus, Proteus mirabilis, Staphylococcus aureus, and Klebsiella pneumoniae. A remarkable finding was the high rates of resistance to cephalosporins among Gram-negative bacteria harboring extended-spectrum beta-lactamase genes, which were associated with carbapenem resistance in a few isolates. This study defined the importance of control of antimicrobial resistance in Bangladesh, and provided suggestions for the future direction of collaborative research on infectious diseases in Bangladesh.

DOI： 10.1265/jjh.72.106

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2016.06.006

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Rotavirus A (RVA) is a dominant causative agent of acute gastroenteritis in children worldwide. G2P[4] is one of the most common genotypes among human rotavirus (HRV) strains, and has been persistently prevalent in South Asia including Bangladesh. In the present study, whole genome sequences of a total of 16 G2P[4] HRV strains (8 strains each in 2010 and 2013) detected in Mymensingh, north-central Bangladesh were determined. These strains had typical DS-1-like genotype constellation. Most of gene segments from DS-1 genogroup exhibited high level sequence identities to each other (>98%), while slight diversity was observed for VP1, VP3, and NSP4 genes. By phylogenetic analysis, individual RNA segments were classified into one (V) or two-three lineages (V-VI or V-VII). In terms of lineages (sublineages) of 11 gene segments, the 16 Bangladeshi strains could be further classified into four clades (A-D) containing 8 lineage constellations, revealing the presence of three clades (A-C) with three lineage constellations in 2010, and a single clade (D) with four constellations in 2013. Therefore, co-existence of multiple G2P[4] HRV strains with different lineage constellations, and change in clades for the study period were demonstrated. Although amino acids in the antigenic regions on VP7 and VP4 were mostly identical to those of global G2P[4] strains after 2000, VP4 of clade D RVAs in 2013 had alanine and proline at positions 88 and 114, respectively, which are novel substitutions compared with recent global G2P[4] strains. Replacement of lineage constellations associated with unique amino acid changes in the antigenic region in VP4 suggested continuous genetic evolutionary state for emerging new G2P[4] rotavirus strains in Bangladesh.

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2016.02.001

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Twenty-two of 1,103 methicillin-resistant Staphylococcus aureus (MRSA) isolates containing the type II staphylococcal cassette chromosome mec element (SCCmec) (collected in Hokkaido, Japan, from 2008 to 2011) harbored the arginine catabolic mobile element (ACME). Five genetic variations were identified in the ACME-staphylococcal cassette chromosome mec composite islands, 66 to 79 kb in size. The percentage of ACME carriage temporally increased from 0.85% to 4.5% in parallel with the emergence of shorter variants (66 to 72 kb). Shorter variants may have a selective advantage and accelerate the dissemination of ACME in Japanese MRSA.

DOI： 10.1128/AAC.02356-15

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2015.12.007

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2015.11.001

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nmni.2015.06.002

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Puerperal infection is a common complication during postnatal period in developing countries. Bacterial species, drug resistance, and genetic characteristics were investigated for a total of 470 isolates from puerperal infections in Bangladesh for a 2-year period (2010-2012). The most common species was Escherichia coli (n=98), followed by Enterococcus faecalis (n=54), Staphylococcus haemolyticus (n=33), Proteus mirabilis (n=32), Staphylococcus aureus (n=27), Klebsiella pneumoniae (n=22), and Enterobacter cloacae (n=21). S. aureus and Acinetobacter baumannii were isolated at a higher frequency from wound infections after cesarean section, while E. coli, E. cloacae, and K. pneumoniae were isolated from community-acquired endometritis and urinary tract infections. Resistance to third-generation cephalosporins was frequent for Enterobacteriacae, and was mainly mediated by blaCTX-M-1 group beta-lactamases. The CTX-M gene in E. coli from the four phylogroups was identified as blaCTX-M-15, and phylogroup B2 isolates with blaCTX-M-15 were classified into ST131 with O25b allele, harboring aac(6')-Ib-cr and various virulence factors. Carbapenemase genes blaNDM-1 and blaNDM-7 were identified in one isolate each of phylogroup A E. coli. Methicillin-resistant S. aureus isolates had type IV or V SCCmec, including isolates of ST361 (CC672), which is related to an emerging ST672 clone in the Indian subcontinent. This study revealed the recent epidemiological status of aerobic bacteria causing puerperal infections in Bangladesh, providing useful information to improve clinical practice and infection control.

DOI： 10.1089/mdr.2014.0219

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Serogroup 6 of Streptococcus pneumoniae contains four established serotypes (6A-6D). Recently, putative serotype 6E (genotype 6E) was proposed as a novel type, which is cross-reactive with 6B-specific antiserum, but its capsular polysaccharide synthesis (cps) locus is genetically distinct from those of serotypes 6A and 6B. In the present study, prevalence of genotype 6E was analyzed by a newly designed multiplex polymerase chain reaction (PCR) for noninvasive or colonizing S. pneumoniae isolates in northern Japan assigned to serogroup 6 in our previous study by the sequential multiplex PCR developed by Pai et al. Among the isolates previously assigned to 6A and 6B, 2.2% (1/45) and 77.3% (140/181) of isolates, respectively, were revealed to have cps genes of genotype 6E. Eight 6E isolates selected for further analysis were found to have identical or highly similar sequences of cps genes (wzg, wzh, wze, wciN, wciP, and wzy) to those of strains previously reported as putative serotype 6E, and all the isolates were classified into sequence type 90 (ST90). Reanalysis of genetic traits on penicillin and macrolide resistance clarified significantly higher rates of three pbp mutations (gPRSP) and ermB in genotype 6E than in serotypes 6A and 6B. These findings suggested a need for detection of genotype 6E in the surveillance of S. pneumoniae serotypes.

DOI： 10.1089/mdr.2014.0181

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Distribution of serotypes, prevalence of resistance to penicillin and/or erythromycin (EM), and its genetic traits were analyzed for a total of 1,061 noninvasive or colonization isolates of Streptococcus pneumoniae (998 and 61 isolates from children and adults, respectively) in Hokkaido, northern main island of Japan, in the year 2011, the pre-PCV7 routine immunization period. Serotype deduction was performed by sequential multiplex polymerase chain reaction (PCR), employing mutagenic PCR-restriction fragment length polymorphism for discrimination of 6A/C and 6B/D. Unaltered three PBP genes and macrolide resistance genes erm(B) and mef(A/E) were detected by multiplex PCR. Among isolates from children, 25 serotypes, including the prevalent types 6B (17.5%), 19F (15.6%), 23F (12.2%), and 6C (11.6%), were identified, revealing the PCV7 and PCV13 coverage rates as 48.2% and 60.3%, respectively, while serotype 3 was the most frequent (19.0%) among isolates from adults. Most of the pediatric isolates (96.8%) exhibited resistance to EM (minimum inhibitory concentration [MIC], ≥1 μg/ml), with a higher prevalence of erm(B) (67.2%) than mef(A/E) (39.7%). erm(B) was associated with high-level EM resistance (MIC, ≥128 μg/ml) and distributed at high detection rates to major serotypes 23F (85.2%) and 6B (85.1%), as well as minor serotypes 3, 10A, 14, 15B, 15C, 19A, and 23A (>90%). While penicillin-resistant S. pneumoniae (PRSP) (penicillin G-MIC, 2-3 μg/ml) was detected in 7.8% of isolates from children, the most common PBP gene genotype was gPRSP (three altered genes pbp1a, 2x, and 2b; 38.3%), which was detected at higher rates (>60%) in the dominant serotypes 23F, 6B, and 19F, and minor serotypes 6D and 15A. Dominant serotypes in the S. pneumoniae isolates were generally similar to those reported for invasive strains, despite lower coverage rates by PCV7/13. The importance of further surveillance on incidence and drug resistance in the post-PCV7 period was suggested for non-PCV7/13 serotypes 6C, 6D, 10A, 15A, 15B, 15C, 23A, and 35B.

DOI： 10.1089/mdr.2013.0196

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Severe skin lesions caused by Staphylococcus aureus infection are associated with production from bacterial cells of Panton-Valentine leukocidin (PVL), a typical virulence factor of community-acquired methicillin-resistant S. aureus (CA-MRSA), as well as other toxins represented by exfoliative toxins. Through a retrospective study of 26 S. aureus strains isolated from skin lesions of diabetic patients admitted to a hospital in Bangladesh, 2 PVL-gene-positive MRSA-IVa strains and 8 PVL-negative, exfoliative toxin D (ETD) gene (etd)-positive MRSA-IVa strains were isolated. A PVL-positive MRSA-IVa strain had a type I arginine catabolic mobile element (ACME), belonged to ST8/agr-type I/spa-type t121 (a variant of t008), and harbored blaZ, tet(K), msrA, and aph(3')-IIIa, which are mostly typical characteristics found in USA300, a predominant CA-MRSA clone in the United States. Another PVL-positive MRSA strain, belonging to ST1929 (CC88)/agr-type III/spa-type t3341, was negative for ACME, but possessed blaZ and tet(K). The etd-positive MRSA-IVa strains possessed the epidermal cell differentiation inhibitor B (EDIN-B)-encoding gene (edinB) and belonged to ST1931 (CC80)/agr-type III/spa-type t11023 (a variant of t044), which was genetic trait similar to that of the European CA-MRSA ST80 clone. However, unlike the European ST80 strains, the etd-positive MRSA strains detected in the present study harbored seb, sek, and seq, while they were negative for tet(K), aph(3')-IIIa, and fusB, showing susceptibility to fusidic acid. These findings suggested that etd-positive ST1931 MRSA strains belong to the same lineage as the European ST80 MRSA clone, evolving from a common ancestral clone via acquisition of a different pathogenicity island. This is the first report of a USA300-like MRSA-IV strain, PVL-positive ST1929 (CC88) MRSA-IV, and European ST80 CA-MRSA-like etd-positive ST1931 (CC80) MRSA-IV strains isolated in Bangladesh.

DOI： 10.1089/mdr.2013.0153

PubMed

researchmap

掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/nmi2.54

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Arginine catabolic mobile element (ACME), a genomic island consisting of the arc and/or opp3 gene clusters found in staphylococcal species, is related to increased bacterial adaptability to hosts. Staphylococcus epidermidis is considered a major ACME reservoir; however, prevalence and genetic diversity of ACME in coagulase-negative staphylococci (CNS) have not yet been well characterized for clinical isolates in Japan. A total of 271 clinical isolates of CNS in a Japanese hospital were investigated for the presence and genotype of ACME and SCCmec. The prevalence of ACME-arcA was significantly higher (p<0.001) in S. epidermidis (45.8%) than in other CNS species (3.7%). ACME in S. epidermidis isolates (n=87) were differentiated into type I (n=33), variant forms of type I (ΔI, n=26) newly identified in this study, type II (n=6), and type ΔII (n=19). ACME-type ΔI, which were further classified into three subtypes, lacked some genetic components between the arc and opp3 clusters in archetypal type I, whereas the arc and opp3 clusters were intact. The arc cluster exhibited high sequence identity (95.8-100%) to that of type I ACME; in contrast, the opp3 cluster was highly diverse, and showed relatively lower identities (94.8-98.7%) to the identical regions in type I ACME. Twenty-one isolates of ΔI ACME-carrying S. epidermidis possessed SCCmec IVa and belonged to ST5 (clonal complex 2). Phylogenetic analysis revealed that isolates harboring ACME ΔI in this study clustered with previously reported S. epidermidis strains with other lineges, suggesting that S. epidermidis originally had some genetic variations in the opp3 cluster. In summary, ACME type ΔI, a truncated variant of ACME-I, was first identified in S. epidermidis, and revealed to be prevalent in ST5 MRSE clinical isolates with SCCmec IVa.

DOI： 10.1016/j.meegid.2013.09.018

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Panton-Valentine leukocidine (PVL) is a distinctive virulence factor of community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA), and arginine catabolic mobile element (ACME) is a staphylococcal genomic island that enhances fitness and the ability of bacterial cells to colonize on skin and mucous membranes. ACME is characteristically found in USA300, which is a predominant CA-MRSA clone [sequence type (ST) 8] in the USA and is spreading globally, and has also been detected in non-ST8 MRSA at low frequency. In Japan, spread of MRSA with PVL and/or ACME and their genetic traits have not yet been well characterized. In the present study, the prevalence and genetic diversity of PVL(+)/ACME(+) MRSA were investigated for 422 MRSA clinical isolates collected from outpatients in northern Japan over a period of 1 year. All the isolates were genotyped for the staphylococcal cassette chromosome mec (SCCmec) and coagulase genes (coa), and screened for PVL and ACME genes. The PVL(+)/ACME(+) isolates were studied further by genetic analysis, including single-nucleotide polymorphism (SNP) analysis based on PVL genes (lukS-PV-lukF-PV), ACME (arc and opp3 clusters) and the sarU promoter region. Among all the isolates examined, PVL genes and ACME were detected in eight (SCCmec-II, n = 1; SCCmec-IV, n = 6; SCCmec-V, n = 1) and 20 (SCCmec-II, n = 14; SCCmec-IV, n = 5; SCCmec-V, n = 1) isolates, respectively. Five isolates were found to have both PVL genes and ACME (type I), and were classified into ST8/spa-t008/agr-I/coa-IIIa, which is the same genetic traits as USA300. Fifteen PVL(-)/ACME(+) isolates had type ΔII-ACME, belonging to either ST5 or ST764 [clonal complex (CC) 5], and spa-t001, -t002 or -t3557. All the ST8 PVL(+)/ACME-I(+) MRSA had identical sequences of PVL genes (haplotype R) and ACME arc/opp3 clusters as those of USA300. In contrast, in the CC5 PVL(-)/ACME-ΔII(+) MRSA, SNPs in the arc cluster were detected in 11 sites (four haplotypes), with some different profiles of virulence/resistance factors. These results indicated single clonality of ST8 PVL(+)/ACME-I(+) MRSA and heterogeneity of CC5 PVL(-)/ACME-ΔII(+) MRSA, and suggest their potential spread in northern Japan.

DOI： 10.1099/jmm.0.062125-0

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Cross-resistance to macrolide, lincosamide, and streptogramin B (MLSB) antibiotics is mainly mediated by the erm (erythromycin ribosome methylation) genes that encode 23S rRNA methylases in enterococi, and various mechanisms are involved in the streptogramin B resistance. Prevalence of MLSB resistance and its genetic mechanisms were analyzed for a total of 159 strains of Enterococcus faecium isolated from clinical specimens in a university hospital in Japan from 1997 to 2006. Resistance to erythromycin (EM) and clindamycin was detected in 88.1% and 89.9% of all the strains examined, respectively, and expression of resistance was totally constitutive. Although none of the strain was resistant to quinupristin/dalfopristin (Q/D), 28 strains (17.6%) showed intermediate resistance to Q/D (MIC: 2 μg/ml). The erm(B) gene was detected in 139 strains (87.4%), and msrC was found in all the strains examined, whereas no other known MLSB resistance genes were identified. The erm(B) regulator region (RR) containing a coding region of the leader peptide was classified into 13 genetic variations (L1-L3, M, S1-S7, D, and R genotypes) in 56 strains. However, no relatedness was identified between the erm(B) RR genotype and EM resistance, or reduced susceptibility to Q/D, although most of Q/D-intermediate strains were assigned to the L1, L2, and S1 genotypes. Q/D-intermediate strains were classified into five multiple-locus variable-number tandem-repeat analysis (MLVA) types, including four types of clonal complex (CC)-C1, five sequence types (STs), including four STs of CC-17, and several resistance gene/virulence factor profiles. The present study revealed the occurrence of Q/D-intermediate E. faecium, which are composed of heterogeneous strains in Japan, and more genetic diversity in the erm(B) RRs than those reported previously.

DOI： 10.1089/mdr.2012.0176

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The ST8 methicillin-resistant Staphylococcus aureus (MRSA) with Staphylococcal cassette chromosome mec (SCCmec) type IVa, known as USA300, is a prevalent community-acquired MRSA (CA-MRSA) clone in the United States and has been spreading worldwide. The USA300 characteristically harbors Panton-Valentine Leukocidin (PVL) genes and the arginine catabolic mobile element (ACME, type I). Prevalence and molecular characteristics of PVL(+) and/or ACME(+) S. aureus were investigated in a university hospital located in northern Japan, for 1,366 S. aureus isolates, including 601 MRSA strains derived from clinical specimens collected from 2008 to 2010. The PVL gene was identified in three MRSA strains with SCCmec IV, which belonged to ST8, spa type t008, coagulase type III, and agr type I. Two PVL-positive MRSA strains had also type I ACME, and were isolated from skin abscess of outpatients who have not travelled abroad recently. One of these PVL(+)/ACME(+) strains carried tet(K), msrA, and aph(3')-IIIa, showing resistance to kanamycin, tetracycline, erythromycin, and ciprofloxacin, suggesting acquisition of more resistance than ST8 CA-MRSA reported in Japan previously. In contrast, another PVL(+)/ACME(+) strain and a PVL(+)/ACME(-) strain were susceptible to more antimicrobials and had less virulence factors than PVL(-)/ACME(+) MRSA strains. Besides the two PVL(+) MRSA strains, ACME (type-ΔII) was identified into seven MRSA strains with SCCmec II belonging to ST5, one of the three spa types (t002, t067, and t071), coagulase type II, and agr type II. These PVL(-)/ACME(+) MRSA strains showed multiple drug resistance and harbored various toxin genes as observed for ST5 PVL(-)/ACME(-) MRSA-II. The present study suggested the spread of ST8-MRSA-IV in northern Japan, and a potential significance of ACME-positive ST5-MRSA-II as an emerging MRSA clone in a hospital.

DOI： 10.1089/mdr.2012.0089

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The Group A rotavirus (RVA) P[10] is a rare genotype of the RVA VP4 gene. To date, the whole genome sequence of only a single P[10] RVA strain, RVA/Human-tc/IDN/69M/1980/G8P4[10], has been determined, revealing a DS-1-like genotype constellation. Whole genomic analyses of P[10] RVA strains with other VP7 genotypes are essential to obtain conclusive data on the origin and genetic diversity of the P10] RVAs. In the present study, the whole genome of a human G4P[10] RVA strain, RVA/Human-tc/IDN/57M/1980/G4P[10], was analyzed. Strain 57M exhibited an unusual G4-P[10]-I1-R1-C1-M1-A1-N1-T2-E1-H2 genotype constellation, and was found to originate from intergenogroup reassortment events involving acquisition of RVA strain 69M-like VP4, NSP3 and NSP5 genes by a co-circulating Wa-like human G4 RVA strain. Although the reference P[10] strain, 69M, exhibits a DS-1-like genotype constellation, the exact origin of this RVA remains to be elucidated. By detailed phylogenetic analyses, we found that the VP1-VP3, VP6, NSP2 and NSP4 genes of 69M originated from artiodactyl and/or artiodactyl-like human P[14] strains, whilst its NSP1, NSP3 and NSP5 genes were more related to those of typical human DS-1-like strains than those of other RVAs. On the other hand, the origin of the VP4 gene of 69M could not be established. Nevertheless, these observations clearly indicated that strain 69M might have originated from reassortment events involving at least the artiodactyl or artiodactyl-like human RVAs and the typical human DS-1-like strains. The present study provided rare evidence for intergenogroup reassortment events involving co-circulating typical human Wa-like RVAs and unusual RVAs of the DS-1-like genogroup, and revealed the presence of artiodactyl-like genes in a human P[10] strain, highlighting the complex evolutionary patterns of the P[10] RVAs.

DOI： 10.1016/j.meegid.2012.10.021

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

OBJECTIVES: The arginine catabolic mobile element (ACME) is a novel staphylococcal genetic island. ACME is located downstream of the staphylococcal cassette chromosome mec (SCCmec), forming the ACME-SCCmec composite island. Recently, ACME II (located upstream of SCCmec IV) was described from a methicillin-resistant Staphylococcus aureus (MRSA) strain M1 in Denmark (ST8-MRSA-IVa) and 15 MRSA isolates in Ireland (ST22-MRSA-IVh). We report the novel genetic characteristics of the ACME-SCCmec composite islands found in Japanese community-acquired MRSA (CA-MRSA) isolates. METHODS: ACME-SCCmec composite islands from two ACME-arcA-positive CA-MRSA isolates with the genotypes ST5-MRSA-V (SR141) and ST5-MRSA-II (SR388) were characterized using long-range PCR and nucleotide sequencing. RESULTS: Both isolates harboured a 12 kb DNA region primarily identified in ACME II in Staphylococcus epidermidis ATCC 12228 upstream of each SCCmec. The arcA and its flanking regions in SR141 and SR388 showed high sequence identity (99.8% at the highest) to those in MRSA M1 and M08/0126 (the representative of 15 Irish ST22-MRSA-IVh isolates), suggesting that the ACMEs of these four isolates originated from the same ancestral gene. The ACME II-like element in SR141 included an insertion sequence IS1182 at a position close to SCCmec, resulting in a new variant. SR388 contained ∼11.5 kb of the J1 region of type I SCCmec (J1 SCCmecI) between orfX and ACME (orfX-J1 SCCmecI-ACME II), unlike the homologous region in M08/0126 (orfX-ACME II-J1 SCCmecI). CONCLUSIONS: This is the first report of the ACME II-like element inserted upstream of SCCmec in CA-MRSA with the genotypes ST5-MRSA-V and ST5-MRSA-II.

DOI： 10.1093/jac/dks157

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Staphylococcus aureus produces virulence factors, including various exotoxins and adhesins, which are associated with a variety of symptoms caused by its infections. In the present study, the prevalence of these virulence factors was analyzed for 23 S. aureus strains isolated from wound infections in hospitals, nasal swabs, or vomit from patients and cooks in a food poisoning case and from healthy adults in Yangon, Myanmar. Among these strains, five were methicillin-resistant S. aureus (MRSA) derived from pus (four strains, SCCmec III, ST239) and a healthy adult (one strain, SCCmec-IVa, ST5). The Panton-Valentine leukocidine (PVL) gene was detected in five methicillin-susceptible S. aureus (MSSA) clinical strains belonging to ST121 (CC121). The MRSA clinical strains had only a few or no staphylococcal enterotoxin (SE) genes, whereas PVL-positive MSSA and an MRSA strain from a healthy adult possessed an enterotoxin gene cluster (seg, sei, sem, sen, seo, and selu). Strains from the food poisoning case had either SE genes or only etd and edin-B. Adhesin genes, which are associated with binding to fibronectin, fibrinogen, and elastin, were detected in all the MRSA and most of the MSSA strains examined. However, the bone sialoprotein-binding protein gene (bbp) and the variant form of the elastin-binding protein gene (ebpS-v) with an internal 180 bp deletion were identified only in the MSSA strains harboring the PVL gene. These findings suggest that those genetic traits are characteristic of PVL-positive ST121 S. aureus strains in Myanmar.

DOI： 10.1089/mdr.2011.0061

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A rare genotype G6P[9] was identified in two human group A rotavirus strains designated as KF14 and KF17, that were detected in stool specimens from children with diarrhea in Japan. VP7 gene sequences of these two strains were identical and genetically closely related to G6 human rotavirus strains reported in European countries and the United States. To our knowledge, this is the first report of detection of a G6 human rotavirus in Japan. For further genetic analysis to elucidate the origin of the G6 rotavirus, nearly full-length sequences of all 11 RNA segments were determined for the KF17 strain. The complete genomic constellation of KF17 was determined as G6-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3, a novel genotype constellation for human rotavirus. Phylogenetic analysis indicated that VP6, VP1-3, and NSP2 genes of KF17 clustered with bovine-like G6 human strains and some animal strains into sub-lineages distinct from those of common DS-1-like G2 human rotaviruses. On the other hand, KF17 genes encoding VP4, NSP1, and NSP3-5 showed high sequence identities to the human G3P[9] strain AU-1, and clustered with AU-1 and some feline strains within the same lineage. These findings suggested that the G6P[9] human rotavirus detected in Japan may have occurred through reassortment among uncommon bovine-like human rotaviruses and human/feline AU-1-like rotaviruses.

DOI： 10.1007/s11262-011-0624-6

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Prevalence and molecular characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) were studied in Hokkaido, the main northern island of Japan. Among the 1,015 S. aureus isolates derived from clinical specimens of outpatients collected in 2009, methicillin resistance gene mecA was detected in 189 isolates (18.6%). The most frequent staphylococcal cassette chromosome mec (SCCmec) type in MRSA was II (83.1%), followed by IV (6.9%) and V (3.2%). MRSA with type II-SCCmec showed multiple drug resistance and harbored various toxin and virulence factor genes except for Panton-Valentine leucocidin (PVL) gene. These isolates were mostly classified into sequence type 5 (ST5) (or other STs in CC5) and coagulase genotype II and were thus genetically similar to hospital-acquired MRSA, which have been predominating in Japan (New York/Japan clone). PVL gene was detected in three MRSA strains belonging to ST6 (two strains) and ST59 (one strain), having type IVa- and Vt-SCCmec, respectively, and also in two methicillin-susceptible S. aureus ST121 and ST188. The arcA gene within the arginine catabolic mobile element (ACME) was detected in the two PVL-negative ST5 MRSA strains, which had type IIa- or V-SCCmec. The PVL gene-positive ST6 and ST59 CA-MRSA strains were susceptible to more antimicrobials and had less virulence factor genes than the PVL-negative ST5 MRSA, including the ACME-arcA-positive strains. In the present study, ST6 was identified as a lineage of PVL-positive CA-MRSA, the ACME-arcA was first detected in ST5 MRSA with type V-SCCmec, and ST59 Taiwanese CA-MRSA strain was isolated in Hokkaido for the first time. These findings suggest a potential spread of these emerging CA-MRSA clones in Japan.

DOI： 10.1089/mdr.2010.0136

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Methicillin resistance in staphylococci is conferred by the acquisition in its chromosome of the mecA gene, which is located on a mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). Genetic type of SCCmec is defined by combination of mec gene complex class and cassette chromosome recombinase gene (ccr) allotype. In this study, we analyzed genetic diversity of the SCCmec in 11 Staphylococcus haemolyticus strains and a Staphylococcus sciuri strain, which were recently isolated from clinical specimens in Bangladesh. Among these strains, only two S. haemolyticus strains were proved to have the known types of SCCmec, that is, SCCmec V (class C2 mec-ccrC) and VII (class C1 mec-ccrC). Five S. haemolyticus strains were assigned two unique mec-ccr gene complexes combination; that is, class C1 mec-ccrA4B4 (four isolates) and class A mec-ccrC (one isolate). In the remaining four S. haemolyticus strains with class C1 mec, no known ccr allotypes could be detected. A single S. sciuri strain with class A mec complex carried a ccrA gene belonging to a novel allotype designated ccrA7, together with ccrB3. The ccrA7 gene in the S. sciuri strain showed 61.7%-82.7% sequence identity to the ccrA gene sequences published so far, and 75.3% identity to ccrA3, which is a component of the type 3 ccr complex (ccrA3-ccrB3) in methicillin-resistant Staphylococcus aureus. The results of the present study indicated that mec gene complex and ccr genes in coagulase-negative staphylococci are highly divergent, and distinct from those of common methicillin-resistant S. aureus. Identification of the novel ccrA7 allotype combined with ccrB3 suggested an occurrence of recombination between different ccr complexes in nature.

DOI： 10.1089/mdr.2010.0144

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Staphylocoagulase (SC) is a major phenotypic determinant of Staphylococcus aureus. Antigenic specificity of SC (SC serotype) has been classified into at least 10 types and employed as an epidemiological marker. In the present study, from the sequence information of SC genes, a novel multiplex PCR assay was developed to determine SC genotypes (SC types) I-X corresponding to SC serotypes I-X, respectively, and to discriminate two subtypes of SC types IV and V. Two PCR reactions (Sc-R1 and Sc-R2) for a single isolate were designed for assigning common SC types in S. aureus isolates from humans (I-VIII and X). When amplicon was not produced, an additional PCR (Sc-R3) was performed to assign SC type IX or subtype Vb. Subtypes IVa and IVb were discriminated by an additional PCR (Sc-R4). SC types were discriminated successfully for the S. aureus strains with established SC types I-X including two subtypes of IV and V. The multiplex PCR assay established in this study could assign SC types for S. aureus clinical isolates at a high determination rate, providing more accurate information on incidence of SC types, and was considered to be useful for epidemiologic characterization of S. aureus.

PubMed

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：日本公衆衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本臨床微生物学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：日本公衆衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本感染症学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：(一社)日本臨床微生物学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：(一社)北海道臨床衛生検査技師会  

医中誌

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

その他リンク:： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2017&ichushi_jid=J01030&link_issn=&doc_id=20170906160003&doc_link_id=1390001206361877632&url=https%3A%2F%2Fcir.nii.ac.jp%2Fcrid%2F1390001206361877632&type=CiNii&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00003_3.gif

医中誌

researchmap

記述言語：日本語   出版者・発行元：(公財)産業医学振興財団  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：日本語   出版者・発行元：(一社)日本感染症学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：日本語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：(一社)日本衛生学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

記述言語：英語   出版者・発行元：日本細菌学会  

医中誌

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap

記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（指名）  

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap