Phenotypic and Genomic Profile of Foodborne Antimicrobial Resistant Staphylococcus aureus Isolated in the Republic of Tajikistan

Introduction: Staphylococcus aureus is a significant infectious agent causing food poisoning. High adaptability and the ability to produce heat-stable enterotoxins make it a dangerous pathogen of public health concern. Monitoring antibiotic resistance and assessing the risk of food contamination by this microorganism are critical to prevent and treat foodborne toxic infections.
Objective: To assess phenotypic and genotypic antibiotic resistance of S. aureus strains isolated from food products on the territory of the Republic of Tajikistan.
Materials and methods: The study included 50 isolates of S. aureus derived from foods in the Republic of Tajikistan in 2018–2022. Species identification was performed by MALDI-TOF MS. Phenotypic susceptibility to antimicrobial agents was determined by the minimum inhibition concentration method using the Sensititre system. Genetic determinants of resistance and virulence were determined by analyzing data from full-genome sequencing using Illumina NextSeq 2000 system.
Results: 44.0 % (22/50) of S. aureus isolates were resistant to at least one antimicrobial drug, of which 34.0 % (17/50) were multidrug resistant. S. aureus with phenotypic and genotypic resistance to beta-lactams were the most common (40.0 %): blaZ resistance genes were detected in 94.0 % (16/17) and mecA in 76.4 % (13/17). The analysis of multilocus sequence typing results revealed 4 different S. aureus sequencing types with ST5 prevailing. A high frequency of virulence genes, including enterotoxins and leukocidins, was also observed.
Conclusion: Food contamination with S. aureus poses a significant threat to public health. High antibiotic resistance of the foodborne microorganisms and the presence of multiple virulence genes highlight the need for continuous monitoring and development of strategies to manage the risks associated with the spread of antibiotic resistance through the food chain.

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