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Molecular Characterization of Streptococcus pyogenes Isolates Recovered from Hospitalized Patients During the Years
Adile A Muhtarova1, Vasil S Boyanov1, Alexandra S Alexandrova1
1Department of Medical Microbiology, Medical Faculty, Medical University of Sofia, Zdrave Str. 2, 1431 Sofia, Bulgaria.
Abstract:
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.
Insights
Severe group A Streptococcus (GAS) infections are rising globally. This study found emm1/A-C3 is now the most prevalent GAS type, with decreased macrolide resistance linked to fewer emm28 clones.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Increasing global incidence of severe *Streptococcus pyogenes* (group A Streptococcus, GAS) infections and antibiotic resistance.
- Need to monitor circulating GAS strains and their antimicrobial susceptibility patterns.
Purpose of the Study:
- Identify prevalent GAS *emm* types and clusters in hospitalized patients.
- Investigate the association between *emm* types and antibiotic susceptibility.
- Compare current findings with pre-pandemic data.
Main Methods:
- Analysis of 70 GAS isolates from inpatients.
- Identification of *emm* types and clusters.
- Antimicrobial susceptibility testing for various antibiotic classes.
- Comparison with historical GAS surveillance data.
Main Results:
- Predominant *emm* types were *emm*1, *emm*3, and *emm*4; predominant clusters were A-C3, E4, and A-C5.
- *emm*1 was most common in skin/soft tissue infections and pneumonia; *emm*3 in peritonsillar abscesses.
- All isolates were susceptible to penicillin and linezolid; resistance rates were 14.3% (macrolides), 14.3% (lincosamides), and 18.6% (tetracyclines).
- Shift in prevalence towards *emm*1/A-C3 compared to pre-COVID-19 data.
- Decreased macrolide resistance correlated with reduced prevalence of the *emm*28 clone.
Conclusions:
- The distribution of GAS *emm* types/clusters has changed, with *emm*1/A-C3 now dominant.
- Continued surveillance of GAS isolates and antibiotic resistance is crucial for public health.
- Understanding *emm* type prevalence aids in managing severe GAS infections and guiding treatment strategies.
