Clinical and molecular characteristics of Staphylococcus aureus isolated from Chinese children:association among the agr groups and genotypes,virulence genes and disease types

摘要

Background This study was aimed to investigate the clinical and molecular epidemiology of Staphylococcus aureus(S.aureus)isolated from Chinese children and determine the possible relationship among the accessory gene regulator(agr)groups and genotypes,as well as among the virulence genes and disease types.Methods S.aureus strains were isolated from Beijing Children''s Hospital between October 2017 and October 2019.The isolates and 19 virulence genes were characterized using multi-locus sequence typing,staphylococcal protein A(spa),staphylococcal cassette chromosome mec,and agr typing.Results A total of 191 non-repetitive S.aureus clinical isolates were divided into 33 sequence types(STs),18 clonal com-plexes(CCs),and 59 spa types.ST59(39.8%),t437(37.7%),and agrⅠ(84.8%)were the predominant types.CC59,CC25,CC22,CC951,CC8,and CC398 belonged to agrⅠ.CC5 and CC15 were assigned to agrⅡ,and CC30 was characterized as agrⅢ.CC121 was classified under agrⅣ.The eta,etb,and bbp genes were more prevalent in agrⅣ(P<0.001 for each),while tst was more prevalent in agr groupⅢcompared to the other groups(P<0.001).Nearly all isolates that harbored lukS/F-PV belonged to agrⅠ(P=0.005).However,the correlation between disease types and agr groups was not significant(P>0.05).Conclusions An association among the agr groups and genotypes,as well as specific toxin genes,was observed among the S.aureus strains isolated from Chinese children.However,a statistical correlation was not found among the agr groups and disease types.