Prevalence of Tetracycline Resistance Genes tet (A, B, C, 39) in Klebsiella pneumoniae Isolated from Tehran, Iran by Multiplex PCR

Background and Objective: Klebsiella pneumoniae is one of the three pathogens that has become a global disease control and treatment problem due to its resistance to common antibiotics. For this reason, it is crucial to study the genes that cause antibiotic resistance in it. Therefore, the aim of this study was to investigate the phenotypic and genotypic frequency of tetracycline resistance in clinical isolates of K. pneumoniae in Tehran, Iran. Materials and Methods: In this study, 100 isolates of K. pneumoniae isolated from clinical samples (urine) during 2018-2019 were studied. In addition to microbial and biochemical phenotypic tests, genotypic tests were conducted to determine the frequency of antibiotic resistance genes tet (A, B, C, 39). Results: Out of 100 isolates of K. pneumoniae, 49 isolates were resistant to tetracyclines. The results of multiplex PCR showed that 31 samples were positive for tetA gene, 8 isolates for tetB gene, 21 samples for tetC and, and 8 isolates for tet39. None of the isolates were positive for all four tetracycline genes. Conclusion: The results of this study showed that the isolates were positive for at least one gene and at most 2 tetracycline resistance genes. The tetA gene showed the highest frequency and the lowest frequency was demonstrated by tetB. The highest binary combination of genes was tetA-tetC, and the lowest was tetA-tet39.