title: Antibiotic resistance and molecular analysis of Streptococcus pyogenes isolated from healthy schoolchildren in China.
abstract: Streptococcus pyogenes are highly prevalent bacterial pathogens, especially in school-aged children. However, the characteristics of asymptomatic carriers vary geographically in different countries. We aimed to investigate S. pyogenes isolated from healthy schoolchildren in China. From 2007 to 2008, a total of 94 S. pyogenes isolates were obtained from healthy schoolchildren in Beijing and Chongqing, China. Antimicrobial susceptibility testing, determination of macrolide resistance genes (ermB, ermA and mefA), emm genotyping, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were performed. The resistance rate to macrolides was 96.8% and to tetracycline was 92.6%. All macrolide-resistant isolates exhibited constitutive resistance; 77 isolates (84.6%) had the ermB gene, while 14 isolates (15.4%) had the ermA gene. Among the macrolide-resistant isolates, the most frequent emm type was emm12 (51.6%), followed by emm22 (14.3%) and ST1815 (8.8%). PFGE analysis revealed 12 different patterns, with a given pattern having the same sequence type (ST) by MLST and the same emm type. In conclusion, the rate of macrolide resistance to S. pyogenes is currently very high in China. This is due primarily to the dissemination of a limited number of clones.
authors.affiliation: Beijing Children's Hospital, Capital Medical University, 56 Nan Lishi Road, Beijing, China.
authors.forename: Hesheng
authors.initials: H
authors.lastname: Chang
authors.forename: Xuzhuang
authors.initials: X
authors.lastname: Shen
authors.forename: Zhou
authors.initials: Z
authors.lastname: Fu
authors.forename: Lan
authors.initials: L
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Shen
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Liu
authors.forename: Sangjie
authors.initials: S
authors.lastname: Yu
authors.forename: Kaihu
authors.initials: K
authors.lastname: Yao
authors.forename: Chengsong
authors.initials: C
authors.lastname: Zhao
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002352:Carrier Proteins / Q000235:genetics; D002353:Carrier State / Q000382:microbiology*; D002648:Child; D002681:China; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D011153:Population; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein