Abstract
Streptococcus pyogenes is a bacterial pathogen that causes a wide spectrum of clinical diseases exclusively in humans. The distribution of emm type, antibiotic resistance and virulence gene expression for S. pyogenes varies temporally and geographically, resulting in distinct disease spectra. In this study, we analyzed antibiotic resistance and resistance gene expression patterns among S. pyogenes isolates from pediatric patients in China and investigated the relationship between virulence gene expression, emm type, and disease categories. Forty-two representative emm1.0 and emm12.0 strains (n = 20 and n = 22, respectively) isolated from patients with scarlet fever or obstructive sleep apnea-hypopnea syndrome were subjected to whole-genome sequencing and phylogenetic analysis. These strains were further analyzed for susceptibility to vancomycin. We found a high rate and degree of resistance to macrolides and tetracycline in these strains, which mainly expressed ermB and tetM. The disease category correlated with emm type but not superantigens. The distribution of vanuG and virulence genes were associated with emm type. Previously reported important prophages, such as φHKU16.vir, φHKU488.vir, Φ5005.1, Φ5005.2, and Φ5005.3 encoding streptococcal toxin, and integrative conjugative elements (ICEs) such as ICE-emm12 and ICE-HKU397 encoding macrolide and tetracycline resistance were found present amongst emm1 or emm12 clones from Shenzhen, China.
Highlights
Streptococcus pyogenes is an important gram-positive bacteria that ranks among the 10 main causes of death from infectious diseases worldwide, with more than 517,000 deaths annually (Carapetis et al, 2005)
Stains of S. pyogenes are often tested for the expression of speA, speC, speG, speH, speI, speJ, speK, speL, speM, ssa, smez, and the enzymeencoding speB and speF genes as genes encoding SAgs, even though speB and speF have been confirmed to encode cysteine protease and streptococcal DNase proteins (Strus et al, 2017)
98.5% of the isolated GAS strains were sensitive to levofloxacin, and this finding is consistent with the rate observed among GAS strains isolated from children in Shanghai, China, but significantly different from the rate observed among GAS strains isolated from Chinese adults (Shen et al, 2018)
Summary
Streptococcus pyogenes (group A Streptococcus, GAS) is an important gram-positive bacteria that ranks among the 10 main causes of death from infectious diseases worldwide, with more than 517,000 deaths annually (Carapetis et al, 2005). Antibiotics are effective and widely used for treating GAS infections, antibiotic resistance, especially to macrolides, is increasing in several countries The rise of antibiotic resistance leads to an increase in mortality, which has become a public health issue of global concern (Wajima et al, 2014; Silva-Costa et al, 2015). This issue has received close attention in China (You et al, 2018, 2020). The antimicrobial sensitivity of GAS strains as well as the relationships among sAg distribution, emm types, and disease categories were analyzed. 42 representative strains of the two main epidemic emm types were analyzed for population structure, genetic diversity, phylogeny, and susceptibility to vancomycin
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