Phenotypic and Genotypic Detection of Extended Spectrum β-lactamase and Carbapenemases Production Including bla TEM, bla PER and bla NDM-1 Genes Among Acinetobacter baumannii Clinical Isolates

Abstract

Background: Acinetobacter baumannii has appeared as an important opportunistic pathogen responsible for nosocomial infections. The rising trend of antibiotic resistance amongst A. baumannii isolates has become a global concern. The most prevalent procedure of resistance is beta-lactamase and carbapenemases production with genes on mobile elements. Objectives: The aim of the current research was to assess antibiotic susceptibility schema and the frequency of TEM, PER, and NDM-1 genes among A. baumannii isolates. Methods: One hundred and eighty three specimens from November 2014 to February 2015 were collected from Golestan and Imam Khomeini hospitals in Ahvaz, Iran. Drug susceptibility tests were carried out by Kirby-Bauer method. Extended spectrum-beta-lactamases (ESBLs) production was determined by the combination disk method and carbapenemases production was determined by the modified hodge test (MHT) according to the CLSI recommendations. TEM, PER, and NDM-1 were detected by PCR. Results: Out of 183 Acinetobacter isolates, 151 (82.5 %) were identified as A. baumannii by standard chemical tests. The highest resistance was determined to ciprofloxacin (97.3 %), whereas the higher rate of susceptibility was observed to colistin (98.7%). 1.3% of the A. baumannii isolates were positive for ESBL in combined disc test. Production of carbapenemase was detected in 47.1% of the A. baumannii isolates using MHT. The prevalence of TEM and PER genes was 36.4 % and 25.1 %, respectively. NDM-1 genes were not detected. Conclusions: The prevalence of carbapenemase positive A. baumannii isolates in the current study makes a serious concern and highlights the need for infection control through antibiotic management protocols and rapid detection of resistant strains.