Abstract

Afreenish Hassan*, Javaid Usman, Fatima Kaleem, Aslam Khan and Zakir Hussain

Acinetobacter baumannii has emerged as a significant nosocomial pathogen, particularly in intensive care units. Isolates of A. baumannii resistant to major groups of antibiotics have been identified. These multi-drug resistant (MDR) organisms are limiting the treatment options. The study was performed to determine the in vitro activity of aminoglycosides, lactam- lactamase inhibitor combinations and tetracyclines against MDR A. baumannii, isolated from a tertiary care hospital. The study was carried out from January, 2009 - August, 2009, at the Department of Microbiology, Army Medical College/National University of Sciences and Technology, Rawalpindi, Pakistan looking after an 1100 bedded tertiary care hospital. Routine clinical specimens were received from various wards. A. baumannii was identified by using standard microbiological procedures. Antimicrobial susceptibility test (gentamicin, amikacin, tobramycin, ampicillin-sulbactam, piperacillin-tazobactam, cefoperazonesulbactam, tetracycline, doxycycline, minocycline, tigecycline,) was performed according to CLSI guidelines using Kirby- Bauer disc diffusion technique. Resistance to carbapenems, fluoroquinolones and the beta-lactams were observed in significant proportion of fifty isolates. Among the aminoglycosides, the isolates were more susceptible to tobramycin than gentamicin and amikacin. Cefoperazone-sulbactam was superior to piperacillin-tazobactam and ampicillin -sulbactam in activity against MDR A. baumannii. Both tigecycline and minocycline were the active agents against most isolates. Multidrug resistant Acinetobacter infections are posing an increasing threat to our population. Minocycline, tobramycin and cefoperazone-sulbactam provide an effective option against infections caused by resistant A. baumannii.