Introduction: Scarlet fever is an acute infection caused by group A β-hemolytic streptococcus, Streptococcus pyogenes. Childcare settings are an important environment for the circulation of pathogens causing upper respiratory tract infections, with asymptomatic carriage playing a significant role in epidemiological control.
Aim: To investigate the asymptomatic carriage of S. pyogenes and other potentially pathogenic microorganisms in nasal and throat swabs among children and staff in two childcare facilities in the municipality of Varna.
Materials and Methods: The study was conducted in 2025 in connection with Project No. 23013 funded by the Science Fund of the Medical University of Varna, entitled “Investigation of Group A Streptococcus pyogenes Carriage among Children and Staff in Childcare Facilities in the Varna Region,” and in accordance with the decision of the Research Ethics Committee (REC) at the Medical University of Varna, No. 142/18.04.2024. A total of 131 individuals were included in the study—112 children and 19 staff members. A nasal swab and a throat swab were collected once from each participant. Identification of the isolated microorganisms was performed using the Phoenix 100 automated system (BD). Fisher’s exact test was used for comparative analysis, while Fisher’s exact test with Monte Carlo simulation was applied to analyze nasal carriage by age.
Results: S. pyogenes was not isolated from any of the samples examined. Resident microbiota was detected in nasal swabs from 99/131 participants (75.6%). Staphylococcus aureus was isolated in 20 participants (15.3%), Streptococcus pneumoniae in 8 (6.1%), and Moraxella catarrhalis with heavy growth in 3 participants (2.3%); a combination of S. aureus and S. pneumoniae was identified in 1 participant (0.8%). In throat swabs, resident microbiota was detected in 129/131 participants (98.5%), while Staphylococcus aureus was isolated in 2 children (1.5%). No statistically significant difference was found between children and staff with regard to nasal carriage (p = 0.157) or throat carriage (p = 0.987). Among the children, no statistically significant differences were observed according to sex or childcare facility. Analysis of nasal carriage by age showed a trend toward differences, although statistical significance was not reached (p = 0.061).
Conclusion: The results provide regional data on the microbial colonization of the upper respiratory tract in the childcare settings studied. The absence of isolated S. pyogenes should be interpreted in the context of the specific study sample and sampling period and does not allow for the conclusion that the pathogen is absent from circulation in the community.
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