Innovative antibiotic selection system for microbial profile in patients with сhronic rhinosinusitis with nasal polyps

Acute bacterial rhinosinusitis, as well as exacerbations of chronic rhinosinusitis, remain a major public health problem today. Antibacterial drugs represent the mainstay of treatment given the appropriate diagnosis. Proper identification of the causative agent is crucial for the selection of optimal antibiotic therapy.
The existing antimicrobial susceptibility testing (AST) methods are insufficient for the selection of optimal antibiotic therapy in chronic rhinosinusitis (CRS) complicated by bacterial infection. For this purpose, the AtbFinder antibiotic selection test system was developed to address the drawbacks of traditional testing methods.
The aim of the study was a comparative analysis of the microbial composition of nasal mucus in patients with rhinosinusitis, as assessed by the standard method and the new test system.
Material and methods. Twenty-five patients with established diagnosis of CRS participated in the study. At the Department of Otorhinolaryngology with Clinic, swabs were collected from the middle nasal passage and placed in a sterile container for 30 minutes, then stored at approximately 4°C without freezing and transported to the laboratory of the Department of Microbiology within 30 minutes after collection. These samples were analyzed using both standard laboratory methods and the AtbFinder system for comparative performance evaluation. Results showed 18 cases of discrepancies between the results obtained using the AtbFinder system on TGV medium and the standard AST method. Analysis of these discrepancies showed that the antibiotics found to be effective by standard AST were classified as ineffective by the AtbFinder system in 18 cases. This indicates that despite the reported sensitivity under monoculture conditions, bacteria continued to grow in wells with antibiotics in the AtbFinder system. Decreased sensitivity was reported for antibiotics such as amoxicillin-clavulanic acid, amoxicillin, cefuroxime, cephalexin, azithromycin, and clarithromycin. While the standard microdilution method demonstrated effective suppression of bacterial growth with these drugs, the AtbFinder system revealed their ineffectiveness in polymicrobial communities.
Conclusion. The results of this study highlight key limitations of traditional AST testing methods in the context of CRS, especially when working with polymicrobial infections. The innovative AtbFinder system, which uses the TGV environment to model complex microbial communities, has demonstrated significant advantages over traditional approaches. The clinical relevance of the system lies in its ability to simulate conditions as close as possible to the real infectious environment.
Keywords: sinusitis, microbiota, bacterium, biofilms, nutrient media, antibiotics, infection, antimicrobial susceptibility
Conflicts of interest. The authors have no conflicts of interest to declare.
Financing. The study was funded by the grant of the Russian Science Foundation No. 24-75-10028 dated July 31, 2024. https://rscf.ru/project/24-75-10028