The resistance rate to tetracyclines and the frequency of resistance genes tetA, tetB, tetC, tetD, tetE, tetG,tetJ and tetY in clinical Enterobacteriaceae isolates from the Hospitals of Tabriz in 2017

Abstract

This study investigat antibiotic resistance features and resistant tetracycline genes distribution in Enterobacteriaceae isolates from Tabriz hospitals, in Iran. Materials and methods: A total of 250 Enterobacteriaceae isolates that were collected from 3 Hospitals in Tabriz, during the first 6 months of 2017, were tested for susceptibility to 20 antibiotics (ampicillin, piperacillin/tazobactam, imipenem, co-amoxiclav, cefepime, ciprofloxacin, ceftazidime, nitrofurantoin, meropenem, aztreonam, cotrimoxazole, fosfomycin, gentamicin, amikacin, nalidixic acid, cefazolin, tetracycline, doxycycline, minocycline, and tigecycline) by the disc diffusion agar (DDA) method and MIC (minimum inhibitory concentration) determination by the agar dilution method for tetracycline and minocycline. To detect eight tetracycline resistance genes, PCR was performed on tetracycline resistance isolates. Results: The resistance rate to tetracycline, minocycline, doxycycline, and tigecycline by the DDA method were 58.8%, 24%, 43.6%, and 0.4%, respectively. The MIC results showed 52% resistance to tetracycline and 22% for minocycline. Percentage of tet genes distribution was tetA (14.4%), tetB (18.4%), tetC (2%), and tetD (4.4%). However, no trace of tetE, tetG, tetJ and tetY genes was detected.