Molecular characterization and antibiotic resistance of clinical Streptococcus dysgalactiae subsp. equisimilis in Beijing, China

• Published in: Infection, genetics and evolution genetics and evolution, 2016-06, Vol.40, p.119-125
• Main Authors: Lu, Binghuai, Fang, Yujie, Huang, Lei, Diao, Baowei, Du, Xiaoli, Kan, Biao, Cui, Yanchao, Zhu, Fengxia, Li, Dong, Wang, Duochun
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Antibiotic resistance; Bacterial Typing Techniques - methods; China; Drug Resistance, Bacterial; Female; Fluoroquinolones - pharmacology; Genetic Variation; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Molecular characterization; Multilocus Sequence Typing - methods; S. dysgalactiae subsp. equisimilis; Streptococcal Infections - microbiology; Streptococcus - classification; Streptococcus - drug effects; Streptococcus - genetics; Streptococcus - isolation & purification; Tertiary Care Centers; Virulence Factors - genetics; Young Adult
• ISSN: 1567-1348; 1567-7257
• DOI: 10.1016/j.meegid.2016.01.030

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is presently considered as a human pathogen associated with clinical infection. We characterized 56 SDSE isolates collected from two tertiary hospitals in Beijing, China. Sixteen distinct emm types/subtypes were detected, dominated by stG245.0 (32.1%), stG652.0 (10.7%), stG6.1 (10.7%) and stG485.0 (10.7%), and a novel stG840.0 variant type was identified. All isolates possessed virulence genes of sagA and scpA, and most carried slo (98.2%), ska (98.2%) and speGdys (35.7%). By multilocus sequence typing (MLST) analysis, 17 individual sequence types (STs) were distinguished, including 7 newly-identified STs (26.8% of isolates), of which ST127 (30.4%), ST7 (12.5%) and ST44 (10.7%) dominated. Meanwhile, pulsed-field gel electrophoresis (PFGE) analysis revealed 33 pattern types (PTs), which were further combined into 16 pattern clusters (PCs), and 59.3% of isolates were distributed into 2 dominant PCs. Notably, emm types had both close relationship and consistency with STs and PFGE PCs. Furthermore, of 56 SDSE isolates, the predominant antibiotic resistances were erythromycin (71.4%), clindamycin (71.4%) and tetracycline (60.7%). Correspondingly, the prevalent resistance genes of macrolide and tetracycline were erm(B) (78.6%) and tet(M) (73.2%). In addition, multiple point mutations of parC, one of fluoroquinolone resistance genes, were observed (accounting for 75%), and were divided into 12 types, with parC 07 as the predominant type. Our data suggested the wide molecular diversity and distinctive regional features of SDSE from clinical infection in Beijing, China. •We characterized 56 Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates collected in Beijing, China.•The isolates were dominated by emm types of stG245.0, stG652.0, stG6.1 and stG485.0.•emm types have close relationship and consistency with MLST STs and PFGE PCs.•The predominant antibiotic resistances were erythromycin, clindamycin and tetracycline.