ABSTRACT
Acinetobacter baumannii causes infections of respiratory, urinary tract, blood stream and surgical sites. Its clinical significance has increased due to its rapidly developing resistance to major groups of antibiotics used for its treatment. There is limited data available on antimicrobial susceptibility of A.baumannii from Saudi Arabia. To determine the patterns of drug resistance of Acinetobacter baumannii and predisposing factors for its acquisition. In this descriptive study, 72 hospitalized patients infected with A.baumannii were studied. The clinical and demographic data of the patients were collected using a predesigned questionnaire. Isolation and identification of A.baumannii from all clinical specimens were done using standard microbiological methods. Antibiotic susceptibility testing was performed by disk diffusion method recommended by Clinical Laboratory Standards Institute. Majority of the isolates [61.1%] were from respiratory tract infections. A.baumannii isolates showed high drug resistance to piperacillin [93.1%], aztreonam [80.5%], ticarcillin, ampicillin, and tetracycline [76.4%, each] and cefotaxime [75%]. Only amikacin showed low rate of resistance compared to other antibiotics [40.3%]. About 36% patients had some underlying diseases with diabetes mellitus [11%] being the predominant underlying disease. High antimicrobial resistance to commonly used antibiotics was seen against A.baumannii isolates. Only amikacin was most effective against it