title: Population structure and characterisation of Staphylococcus aureus from bacteraemia at multiple hospitals in China: association between antimicrobial resistance, toxin genes and genotypes.
abstract: Staphylococcus aureus from bacteraemia at multiple hospitals in China were genetically characterised to improve understanding of its epidemiology. A total of 236 consecutive, non-duplicate S. aureus bacteraemia isolates were collected at 16 Chinese hospitals. Isolates were characterised by antimicrobial resistance, 19 toxin genes, agr alleles, multilocus sequence typing and spa typing. The prevalence of meticillin-resistant S. aureus (MRSA) was 47.5% (112/236). Forty-two sequence types (STs) and 63 spa types were identified, including 14 STs and 14 spa types for MRSA. Clonal complex (CC) 8, CC5, ST7 and CC188 accounted for 67.4% of the isolates. ST239-t030/t037-SCCmecIII-agrI was the predominant MRSA genotype (50%), followed by ST5-t002/t570-SCCmecII-agrII (8%). A vancomycin MIC ≥ 1mg/L was detected significantly more often in ST5-SCCmecII and ST239-t037-SCCmecIII, whereas rifampicin resistance was overwhelmingly associated with ST239-t030-SCCmecIII (P<0.001). Oxacillin MICs were relatively low for ST59-MRSA. Major genotypes of meticillin-susceptible S. aureus (MSSA) were ST7-t091/t796-agrI (16.1%), ST188-t189-agrI (12.1%) and ST398-t571/t034-agrI (5.6%). Toxin genes were identified in 95.8% of isolates and formed 89 toxin gene profiles. The toxin genes sea, selk, selq and sell were significantly more common in MRSA, whilst tsst-1, seb, sed, selm, seln, selp and selj were more prevalent in MSSA (P<0.001). The pvl gene was more commonly detected in CC59, whereas tsst-1 was more frequent in CC15, CC188 and ST398 (P<0.001). The major genotypes were associated with specific antimicrobial resistance and toxin gene profiles.
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, China.
authors.forename: Wenqiang
authors.initials: W
authors.lastname: He
authors.forename: Hongbin
authors.initials: H
authors.lastname: Chen
authors.forename: Chunjiang
authors.initials: C
authors.lastname: Zhao
authors.forename: Feifei
authors.initials: F
authors.lastname: Zhang
authors.forename: Henan
authors.initials: H
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
mesh_terms: D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology; D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002681:China / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004768:Enterotoxins / Q000235:genetics*; D005838:Genotype; D006801:Humans; D016106:Methicillin Resistance / Q000235:genetics; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010068:Oxacillin / Q000494:pharmacology; D015995:Prevalence; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D014640:Vancomycin; D010068:Oxacillin
keywords: Bacteraemia; Genotype; Staphylococcus aureus; Toxin genes