The Mechanism of Resistance in AmpC-Producing Escherichia coli Isolated from Urinary Tract Infections

AmpCβ-lactamases are capable of hydrolyzing all β-lactams except cefepime and carbapenems. The detection of AmpC-producingEscherichia colihas a high priority in infection management. This research is aimed to investigate the resistant AmpC-generating E.coliisolates and identify their genetic variety.

In this study, 230 E. coliisolates from patients having urinary tract infection symptoms were investigated in 2017-2018 to assess their susceptibility toward antimicrobial agents. AmpC genes were evaluated by PCR and molecular typing using the 10-loci MLVAmethod. MLVA images were examined by BioNumerics 6.6software through the use of the UPGMA algorithms.

The highest frequencies of susceptibility among E. coliisolates were to meropenem 96.08%, piperacillin-tazobactam 90.43%, followed by gentamicin 66.54%, ceftazidime 50%, ciprofloxacin 48.26%, ceftriaxone 41.74%. All E. coliisolates were resistant to amoxicillin-clavulanate. Thirty-eight AmpC-generating E. coliisolates were detected. The most abundant determinant was CIT and EBC, FOX,and DHAhad the next ranks, respectively. Six major clusters and a singleton were identified by MLVA.

AmpC-generation ability is an effective feature in the resistance of E. coliisolates and its investigation is of crucial significance in infection management. The major mechanisms of AmpC beta-lactamase vary depending on time and geographical location