Molecular epidemiological analysis of Streptococcus pyogenes strains isolated from the adult and pediatric patients in Shanghai,China
- VernacularTitle:上海成人和儿童患者分离的A群链球菌分子流行病学分析
- Author:
Haoqin JIANG
;
Mingliang CHEN
;
Tianming LI
;
Hong LIU
;
Mei ZENG
;
Min LI
- Publication Type:Journal Article
- Keywords:
Streptococcus pyogenes;
antimicrobial susceptibility testing;
multilocus sequence typing;
emm typing;
pulsed field gel electrophoresis;
biofilm;
virulence factor
- From:
Chinese Journal of Infection and Chemotherapy
2015;(3):222-229
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate and compare the molecular epidemiological characteristics of Streptococcus pyogenes isolates from Shanghai adult and pediatric patients in terms of antimicrobial susceptibility ,clone type ,emm type ,biofilm formation and virulence for better infection control and treatment .Methods Thirty‐nine nonduplicate clinical isolates of S . pyogenes from adult and pediatric patients were analyzed by determining the susceptibility to antimicrobial agents by Kirby‐Bauer method;clonal typing by multilocus sequence typing ( MLST ); genotyping by emm gene sequence analysis ,which encoding M protein;genomic characteristics of different emm type strains by pulsed field gel electrophoresis (PFGE );and biofilm formation by semi‐quantitative biofilm formation test . Twenty main virulence genes of S .pyogenes ,including 12 superantigen genes and 8 other key genes were detected by PCR and gel electrophoresis . Results A total of 39 nonduplicate S .pyogenes isolates were analyzed .The most common genotype was emm 12‐ST36 (64 .1% ) and emm 1‐ST28 (17 .9% ) .Isolates from adult and pediatric patients had the same dominant genotype , emm 12‐ST36 . The isolates from children showed significantly higher resistance rate to erythromycin and clindamycin than those from adult patients (P<0 .000 1) .Particular emm type and clone type were frequently identified in the same PFGE cluster .Statistical analysis showed that biofilm formation was significantly associated with emm type 1 (P=0 .005) and erythromycin/clindamycin resistance (P=0 .000 3) .The strains from children showed higher biofilm formation than those from adult patients (P<0 .000 1) .We found that virulence genes speA ,speJ and spd3 were significantly associated with emm type 1 (P<0 .000 1 ,P=0 .005 5 ,P<0 .000 1) ,while speI and sic were significantly associated with emm type 12 (both P<0 .000 1) .We also found that the prevalence of speC ,speH ,ssa , smeZ ,and sdaD genes was significantly different between emm type 12 and emm type 1 (P= 0 .023 8 , P< 0 .000 1 , P<0.0001,P= 0.0003,and P= 0.0068,respectively).TheprevalenceofvirulencegenesspeH,smeZandsdaDwas significantly different between the emm type 12 strains from children and those from adults (all P< 0 .000 1) .Conclusions There is a strong agreement between emm type ,clone type ,virulence genes and the clusters defined by PFGE profiling of S . pyogenes .S .pyogenes isolates from adult and pediatric patients are different in terms of antibiotic resistance and biofilm formation .Certain emm type is significantly associated with antibiotic resistance and virulence ,which is useful for infection control .Dominant virulence genes may be the potential target for developing new vaccine to reduce S .pyogenes infection in the future .
