Antimicrobial Resistance Pattern of Acinetobacter baumannii Strains Isolated from Intensive Care Unit Patients

Acinetobacter baumannii is an opportunistic pathogen that affects different groups of people, especially intensive care unit (ICU) patients. The prevalence of infections caused by this bacterium is very high. Today, prevalence of infections caused by multidrug-resistant (MDR) and extreme-drug resistant (XDR) strains is increasing. This study aimed to determine the antibiotic susceptibility pattern of A. baumannii isolates from ICU patients. This cross-sectional study was conducted from October 2014 to March 2015 on patients admitted to ICU of Imam Khomeini hospital in Tehran, Iran. Clinical samples of various sources were collected from patients. Isolates were detected and identified via microbiological and biochemical tests as well as PCR amplification of the blaOxa51 gene. Then, susceptibility testing was performed using the Kirby-Bauer disk diffusion test. Statistical analysis was performed with SPSS (version 22, Chicago, IL, USA) using Chi-square and Fisher’s exact tests. Of the total of 62 clinical samples, 24 (39%) were respiratory samples and only three (6%) were cerebrospinal fluid samples. Most MDR and XDR strains were isolated from respiratory samples. The highest resistance rate was against ceftriaxone, ticarcillin and erythromycin (100%), while the lowest resistance rate was against to minocycline (20%). Owing to detection of high multi-drug resistance isolates in the present study, and importance of multi-drug resistance in A. baumannii, the identification of multi-drug resistance genes and their reporting to health care/treatment centers is important. Thus, it is recommended to perform susceptibility testing to help determine the most effective antibiotic(s) for the treatment of infections in ICU patients