the survey for ampc beta-lactamase production and characterization of antibiotic resistance profile in clinical isolates of klebsiella oxytoca

Background: Klebsiella oxytoca is opportunistic pathogen that in­criminated in many nosocomial infections. There is an increase in the prevalence of resis­tance to different classes of antibiotics in Kleb­siella species. In some isolates resistance is mediated by the production of AmpC beta-lactamases. The goal of this study was the survey for AmpC β-lactamase production and characterization of antibiotic resistance profile in Iranian (Shiraz) clinical isolates of Klebsiella oxytoca. Materials & Methods: In this cross-sectional study, thirty-five Klebsiella oxytoca strains were isolated from patients hospitalized in Shiraz (Iran) hospitals, and subculture was performed on microbiological media including MacConkey agar. The isolates were identified based on biochemical tests embedded in the API-20E system. Standard susceptibility testing (disc diffusion) was performed according clinical and laboratory standards institute (CLSI, 2014) guidelines. Phenotypic detection of AmpC beta-lactamasec was performed by cefepime and cefoxitin disk test. Results: Total 35 Klebsiella oxytoca isolates were examined that among them 4 (11.4%) isolates were AmpC beta-lactamase producing. Among examined antimicrobials, imipenem (100%) and colistin (100%) were most effective drugs against isolates. Respectively, 88.6%, 88.6%, 85.7% and 85.7% isolates were resistant to amikacin, cefoxitin, ciprofloxacin and cefepime. Strains showed the most frequent resistance to ceftazidime (20%). All AmpC beta-lactamase positive isolates were sensitive to amikacin, imipenem and colistin. Conclusion: Results of current study showed third-gerneration cephalosprins are not effective against 20% of infections caused by Klebsiella oxytoca. Resistance to two major classes of antibiotics (aminoglycosides and beta-lactams) was seen among studied strains and treatment of infections causing by this isolates are major problem in future.