Nasopharyngeal microbiota characteristics in children and adults

Background: Nasopharyngeal microbiota plays a crucial role in maintaining respiratory tract health; however, its composition and changes in time can vary significantly with age. Opportunistic microorganisms commonly present in the nasopharynx are not always associated with disease, necessitating a rational approach to interpreting bacteriological findings. Aim: To examine the composition of nasopharyngeal microbiota in healthy residents of Saint Petersburg. Methods: The study included two groups: children (n = 5) and adults (n = 5). Nasal and throat swabs were collected from all participants every two days over a 10-day period. Samples were cultured on nutrient media, followed by microorganism identification and antibiotic susceptibility testing. Results: Significant differences in microbiota composition were observed between the groups. Opportunistic bacteria (e.g., Haemophilus influenzae, Streptococcus pneumoniae) were more frequently detected in children, whereas adults exhibited a predominance of commensal flora (Corynebacterium spp., Streptococcus viridans). High variability of microbiota in children was noted, reducing the clinical value of single-timepoint bacteriological tests. Conclusion: The findings highlight the importance of a balanced approach to interpreting microbiological data. Clinicians should consider that the presence of opportunistic microorganisms may be transient and not necessarily indicative of active disease. Particular attention should be paid to diagnostics in children, as shifts in microbiota composition may represent a natural process rather than a sign of illness. In this context, it is advisable to consider clinical manifestations alongside laboratory findings to avoid unwarranted antibiotic use and reduce the risk of antimicrobial resistance.