Streptococcus pyogenes is regarded as susceptible to β-lactam antibiotics. The guidelines of the Clinical and Laboratory Standards Institute (CLSI) are widely recognized and have long-recommended penicillin for treatment of S. pyogenes infections. There is no CLSI guideline for the treatment of S. pyogenes infections that have intermediate susceptibility or resistance to penicillin. However, there have been several reports of S. pyogenes isolates that are nonsusceptible or even resistant to β-lactam antibiotics, mostly from Chinese journals. The purpose of this commentary is to show data from the literature which suggests the presence of S. pyogenes isolates that are not susceptible to β-lactam antibiotics and whether these strains are really nonsusceptible to β-lactam antibiotics and the presence of mutation in the pbp2x gene requires further research and confirmation.

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.

monitor infectious diseases in China. Their microbial specimens are mainly collected from infectious disease cases. Scarlet fever is a notifiable respiratory infectious disease in China. However, pharyngeal tonsillitis is not notifiable, and thus has not been under surveillance of the CDC. In addition to scarlet fever and pharyngeal tonsillitis, S pyogenes can cause other diseases, such as pneumonia, bronchitis, impetigo, erysipelas, septicaemia, meningitis, necrotising fasciitis, and streptococcal toxic shock syndrome. These diseases are also not under the supervision of the CDC. Therefore, we must do more studies of these manifestations of S pyogenes infection, and pay closer attention to them in a clinical setting, in addition to scarlet fever in China.This research was funded by Sanming Project of Medicine in Shenzhen (SZSM201512030) . DY and YL contributed equally. We declare no competing interests.