Prevalence and Resistance Profile of Clinical Isolates of Acinetobacter Species from Karachi, Pakistan

Abstract

Acinetobacter baumannii causes a variety of infections including pneumonia, urinary tract infection, bacteremia, peritonitis etc. This organism is developing resistance to a number of antibiotics due to various intrinsic and acquired antibiotic resistance genes. The aim of the present study was to determine the prevalence of antibiotic-resistant Acinetobacter species from Karachi, Pakistan. A total of 111 strains of Acinetobacter baumannii and 8 strains of non-baumannii Acinetobacter were isolated from various hospitals of Karachi from September 2013 to December 2014. Identification of the isolates was based on the standard biochemical tests and detection of OXA-51 and OXA-23. Antibiotic resistance profile of the isolates was determined by Kirby-Bauer disc diffusion method and Minimum Inhibitory Concentration (MIC) was also determined by broth macro-dilution method. Among 111 Acinetobacter baumannii isolates, 8 were pan-drug resistant (PDR) and 103 isolates were multidrug resistant (MDR) while all non-baumannii Acinetobacter were MDR. The effective antibiotics against A. baumannii were colistin, gentamicin, trimethoprim/sulfamethoxazole and ciprofloxacin with MIC₅₀ value 1, 256, 256, 256µg/ml, respectively. These findings strongly suggest the proper detection and reporting of PDR/MDR Acinetobacter from clinical samples and also the judicious use of broad-spectrum antibiotics is necessary to prevent the further spread of resistant strains of Acinetobacter.