High Prevalence of Macrolide-resistance and Molecular Characterization of Streptococcus pyogenes Isolates Circulating in China from 2009 to 2016.

Binghuai Lu,Xingchun Chen,Fengxia Zhu,Yanyan Fan,Junrui Wang,Lei Huang,Lei Huang,Yi Li,Yujie Fang,Yujie Fang,Yanchao Cui,Yanchao Cui,Ji Zeng,Dong Li,Dong Li,Zhijun Zhang,Hongxia Li,Duochun Wang,Duochun Wang

doi:10.3389/fmicb.2017.01052

Abstract

Streptococcus pyogenes, or group A Streptococcus, is a pathogen responsible for a wide range of clinical manifestations, from mild skin and soft tissue infections and pharyngitis to severe diseases. Its epidemiological characteristics should be comprehensively under surveillance for regulating the national prevention and treatment practice. Herein, a total of 140 S. pyogenes, including 38 invasive and 102 noninvasive isolates, were collected from infected patients in 10 tertiary general hospitals from 7 cities/provinces in China during the years 2009–2016. All strains were characterized by classical and molecular techniques for its emm types/subtypes, virulent factors and antibiotic resistance profiling. Of 140 isolates, 15 distinct emm types and 31 subtypes were detected, dominated by emm12 (60 isolates, 42.9%), emm1(43, 30.7%), and emm89 (10, 7.1%), and 8 new emm variant subtypes were identified. All strains, invasive or not, harbored the superantigenic genes, speB and slo. The other virulence genes, smeZ, speF, and speC accounted for 96.4, 91.4, and 87.1% of collected isolates, respectively. Further multilocus sequence typing (MLST) placed all strains into 22 individual sequence types (STs), including 4 newly-identified STs (11, 7.9%). All isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, and vancomycin, whereas 131(93.5%), 132(94.2%), and 121(86.4%) were resistant to erythromycin, clindamycin, and tetracycline, respectively. Our study highlights high genotypic diversity and high prevalence of macrolide resistance of S. pyogenes among clinical isolates circulating in China.

Highlights

Streptococcus pyogenes, or Lancefield group A streptococcus, is an essential cause of morbidity and mortality worldwide nowadays, leading to a wide range of human infections, ranging from mild to life-threatening invasive infections (Koutouzi et al, 2015; Plainvert et al, 2016).A variety of virulence factors contribute to pathogenesis
8 new emm types/subtypes were newly-identified in current study, those emm sequences were submitted to GenBank under accession number KY697798KY697805
S. pyogenes is an important pathogen involved in a wide variety of human infections and a major cause of morbidity and mortality worldwide, ranging from noninvasive diseases, such as acute pharyngitis, to life-threatening invasive infections, such as sepsis and toxic shock syndrome (Gherardi et al, 2015)

Summary

Introduction

Streptococcus pyogenes, or Lancefield group A streptococcus, is an essential cause of morbidity and mortality worldwide nowadays, leading to a wide range of human infections, ranging from mild to life-threatening invasive infections (Koutouzi et al, 2015; Plainvert et al, 2016).A variety of virulence factors contribute to pathogenesis. The M protein, encoded by emm gene, is a surface protein and virulence factor of S. pyogenes, capable of adhering to the epithelium and conferring protection against macrophage killing (Sanderson-Smith et al, 2014) It harbors a highly variable region with the antigen, and the protective role of M-protein type-specific antibody has been confirmed (Baroux et al, 2014; Sanderson-Smith et al, 2014). A new emm-cluster typing system that classifies the many S. pyogenes emm types into 48 discrete emm clusters containing closely related M proteins that share binding and structural properties has been proposed (Sanderson-Smith et al, 2014) This system might predict the M protein vaccine antigen content and serve as a framework to investigate the crossprotection phenomenon between different emm-types (Baroux et al, 2014; Sanderson-Smith et al, 2014)

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