The rate of resistance to tetracyclines and distribution of tetA, tetB, tetC, tetD, tetE, tetG, tetJ and tetY genes in Enterobacteriaceae isolated from Azerbaijan, Iran during 2017

Introduction: Enterobacteriaceae are the heterogeneous group of Gram-negative bacteria, which cause different infections. The incidence of resistance to antibiotics among the Enterobacteriaceae is growing. This study investigated antibiotic resistance features and tetracycline resistance genes distribution in Enterobacteriaceae isolates from Hospitals of Azerbaijan, Iran. Methods: The disc diffusion agar and agar dilution methods were used for assessment of antibiotics susceptibility patterns and minimum inhibitory concentration determination of tetracycline and minocycline. To detect eight tetracycline resistance genes (tetA, tetB, tetC, tetD, tetE, tetG, tetJ, and tetY), the PCR was performed in tetracycline-resistant isolates. Results: The resistance rate to tetracycline, minocycline, doxycycline, and tigecycline by the disc diffusion agar method were 58.8%, 24%, 43.6% and 0.4%, respectively. Fifty-one (20.4%) isolates were multiple drugs resistant. The minimum inhibitory concentration results showed 52% resistance to tetracycline and 22% for minocycline. The percentage of tet genes distribution was tetA (14.4%), tetB (18.4%), tetC (2%) and tetD (4.4%). However, tetE, tetG, tetJ and tetY genes were not detected in the present study. Conclusion: There is a moderate-high resistance rate to tetracycline among Enterobacteriaceae in Azerbaijan. The most effective antibiotic against Enterobacteriaceae was tigecycline followed by fosfomycin, imipenem and meropenem. The tet genes family especially tetA and tetB were prevalent among tetracycline-resistant isolates.