Phenotypic and Genotypic Detection of AmpC Enzymes in Clinical Isolates of Escherichia coli and Klebsiella pneumoniae

Abstract

Background: AmpC β-lactamase enzymes cause multi-drug resistance. Aim and Objectives: The purpose of this study is detection of AmpC enzymes in the isolated strains of E. coli and K. pneumonia in three educational hospitals in Hamadan (Iran). Materials and Methods: One hundred and forty strains of E. coli and K. pneumonia were isolated from the hospitals in Hamadan from March to September 2015. To detection of phenotypic AmpC activity, the AmpC detection disks were used. To detect genes encoding for AmpC PCR method was used. Results: Sixty eight isolates (48.5%) were resistant to third generation cephalosporin and of these 61 (43.5%) isolates had MIC ³ 8 μg/mL to cefoxitin. All 68 isolates were analyzed by AmpC detection disks, of which 10 (7.14%) isolates were AmpC- β-lactamase producers. By PCR method, 24 (35.2%) isolates had cit and 48 (70.5%) were positive for fox, 42 (61.7%) for ebc, 46 (67.6%) for mox genes. None of the dha and acc genes were identified. Conclusion: High resistance to cephalosporins has been observed among the clinical isolates. Due to the possibility of plasmid transferring of ampC genes between bacterial, changing consumption patterns of antibiotics and the treatment protocols is necessary.

Keywords

• Escherichia coli
• Klebsiella pneumoniae
• AmpC
• Multi-Drug Resistance
• Beta Lactamase