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.

Epidemiological and molecular characteristics of clinical isolates of Streptococcus pyogenes collected between 2005 and 2008 from Chinese children

“…The S. pyogenes isolates from mainland China had the highest antibiotic resistance to macrolides (.95 %) and virulence (harbouring speA and speC genes). The importance of the emm1.0 and emm12.0 genotype S. pyogenes isolates had been observed previously (Chang et al, 2010(Chang et al, , 2011Liang et al, 2008;Liu et al, 2009). Thus, the rise in scarlet fever cases in Hong Kong was inferred to be a logical phenomenon.…”

Carriage of Streptococcus pyogenes in Primary School Children: M-Protein Types, Pyrogenic Toxin Genes, and Investigation of the Clonal Relationships Between the Isolates

“…Birçok farklı ülkede, asemptomatik çocuklardan izole edilen suşlarla yapılan çalışmalarda da, yine en sık olarak emm1 ve emm12 tipleri saptanmıştır 24,25 . Bu bulgular, çalışmamızda saptadığımız verilerle uyumludur.…”

Multicenter Study of Molecular Epidemiology and Antibiotic Resistance of Group A Streptococci in 2008-2009 in Korea

“…A macrolide is the first choice for patients allergic to penicillin. There have been many reports on the increase in macrolide or CLI resistance rate in many countries [5][6][7][8]. The resistance rates to these antibiotics exceeded 95% in China recently [7].…”

“…There have been many reports on the increase in macrolide or CLI resistance rate in many countries [5][6][7][8]. The resistance rates to these antibiotics exceeded 95% in China recently [7]. On the other hand, there were several reports on the decrease of the antibiotic resistance rate lately, including in Korea [14], Spain [15,16], Finland [17], and Japan [18].…”