Investigation of Prevalence of Extended-Spectrum β-Lactamase PER Gene in Acinetobacter baumannii Isolated from Hospitalized Patients in Qom Province (Iran)

Acinetobacter baumannii has been known as a cause of nosocomial infections in hospitalized patients, especially in intensive care unit. Various types of extended-spectrum beta-lactamases (ESBLs) are responsible for resistance to beta-lactam antibiotics in different parts of the world. The aim of this study was to investigate antibiotic resistance in A. baumannii isolates and the frequency of PER type ESBL producing strains isolated from hospitalized patients.
In this descriptive cross-sectional study, 108 A. baumannii isolates, were investigated in Qom province during the October 2013-2014. Antibiotic resistance pattern of the isolates was examined using disk diffusion method. Minimum inhibitory concentration of ceftazidime antibiotic of the isolates, was determined using microdilution method. Production of ESBLs was determined by double disk synergy test (DDST) and the presence of PER type ESBL gene by PCR method.
The results of antibiotic resistance testing showed that the highest resistance was to antibiotics aztreonam (99.7%) and cefotaxime (98.1%) and the least resistance was to colistin (11.1%) and polymyxin B (0.9%). The Minimum inhibitory concentration of ceftazidime was higher than 128 μg/ml in 86% of the isolates. Among the ceftazidime resistant isolates, 23 (21.3%) isolates were ESBL positive by phenotypic method and 19 (17.6%) isolates carried beta-lactamase PER genes.
The results of this study showed that the prevalence of ESBL-producing A. baumannii isolates can cause serious problems; therefore, their rapid identification is necessary for the control of dissemination of ESBL genes.