Prevalence of β-lactamase-encoding Genes in Isolated Acinetobacter baumannii From Clinical Samples in Sari, Iran

The prevalence of Acinetobacter baumannii as a causative agent of hospital-acquired infections, particularly in burn units and intensive care units, is a major concern due to its innate and acquired resistance to several antibiotics. The presence of beta-lactamase-encoding genes in this bacterium has made it resistant to carbapenems as the last-resort antibiotics for treating infections caused by A. baumannii. This study aims to determine the prevalence of β-lactamase-encoding genes and antibiotic resistance of A. baumannii isolates from burn patients in northern Iran.

In this descriptive cross-sectional study, A. baumannii isolates were obtained from clinical samples of patients in Zare Burn Hospital in Sari City, from 2013 to 2015. The isolates’ antibiotic sensitivity was determined using the disk diffusion method. To investigate the prevalence of β-lactamase genes (blaVIM, blaIMP, and INT), the PCR test was conducted.

Of 150 patients, 54.7% were men and 45.3% were women. The highest resistance rateswere against ceftazidime, cefepime, meropenem, imipenem, ciprofloxacin, amikacin, gentamicin, and colistin in order. It was observed that 31% of the isolates produced metallo-β-lactamase enzyme. The genes blaVIM, blaIMP, and INT were detected in 35%, 45%, and 60% of the isolates, respectively.

A. baumannii isolates have significant resistance to cephalosporins and carbapenems. It is recommended to avoid the irrational prescription of cephalosporins and carbapenems for infections
caused by A. baumannii.