Molecular Characterization of Streptococcus pyogenes Isolates Recovered from Hospitalized Patients During the Years...

In recent years, the incidence of severe Streptococcus pyogenes (group A Streptococcus, GAS) infections has been increasing worldwide, similar to trends observed prior to the COVID-19 pandemic, alongside a rise in antibiotic resistance. In the present study, we identified the circulating 12 emm types and 8 clusters of 70 GAS isolates among inpatients, investigated their association with antibiotic susceptibility, and compared these findings with earlier research conducted in our country. The predominant emm types and clusters were emm1, emm3, and emm4, and A-C3, E4, and, A-C5, respectively. emm1 was the most common among patients with skin and soft tissue infections or pneumonia, while emm3 was detected in patients with peritonsillar abscesses. All isolates demonstrated susceptibility to penicillin and linezolid, whereas the prevalence of resistance to macrolides, lincosamides, and tetracyclines was found to be 14.3%, 14.3%, and 18.6%, respectively. A notable change in the distribution of emm-types/clusters has been observed, with emm1/A-C3 now identified as the most prevalent, differing from our previous study conducted in the pre-COVID-19 period. Additionally, we noted a decrease in resistance to macrolides attributed to a lower prevalence of emm28 clone. The current research is important for monitoring isolates responsible for severe infections, which is crucial for GAS surveillance.