Molecular epidemiology and antimicrobial susceptibility of AmpC- and/or extended-spectrum (ESBL) ß-lactamaseproducing Proteus spp. clinical isolates in Zenica-Doboj Canton, Bosnia and Herzegovina.

Abstract

Aim To investigate prevalence, antimicrobial susceptibility, molecular characteristics, and genetic relationship of AmpC- and/or extended spectrum beta lactamase (ESBL)- producing Proteus spp. clinical isolates in Zenica-Doboj Canton, Bosnia and Herzegovina. Methods Antibiotic susceptibility was determined by disc diffusion and broth microdilution methods according to CLSI guidelines. Double-disk synergy test was performed in order to screen for ESBLs, and combined disk test with phenylboronic acid to detect AmpC β -lactamases. PCR was used to detect blaESBL/blacarb genes. Genetic relatedness of the strains was determined by pulsed-fieldgel-electrophoresis (PFGE). Results Eleven ESBL-producing isolates were included in the study (six inpatients and five outpatients). Susceptibility rate to amoxicillin-clavulanic acid, imipenem and meropenem was 100%. Resistance rate to cefuroxime was 100%, gentamicine 90.9%, piperacillin/tazobactam 81.8%, cefotaxim, ceftriaxone and ceftazidime 72.7%, cefoxitine and ciprofloxacine 63.6% and to cefepime 45.5%. In five (out of 11) isolates multi-drug resistance (MDR) to cephalosporins, cefamicines, amynocligosides and fluoroquinolones was detected. Besides TEM-1 which was detected in all isolates, CTX-M+OXA-1 β-lactamases were detected in seven (out of 11; 63.6%) isolates (five blaCTX-M-1 and two blaCTX-M-15 genes), and CMY-2 β-lactamase in two isolates. PFGE showed no genetic relatedness. Conclusion Because of high prevalence of MDR strains in epidemiologically unrelated patients with AmpC- and/or ESBL producing Proteus spp. infection, further surveillance is needed. Molecular characterization and strain typing, or at least phenotypic test for AmpC/ESBL production is important for appropriate therapy and the detection of sources and modes of spread, which is the main step in order to design targeted infection control strategies.