Evaluation of antibiotic resistance of clinical Acinetobacter baumannii isolated of Tabriz hospital by disk diffiusion and MIC methods

Acinetobacter baumannii is an emerging pathogen of growing significance that has been more frequently isolated in nosocomial specimens. These bacteria have ability of gene transfer between its types and other bacteria as caused for resistance against antibiotics and resistance scattering of bacteria. The aim of this research is determination of resistance for antibiotics and minimum extent of MIC concentration and separated Acinetobacter baumannii isolates in Tabriz hospital. 61 clinical samples were collected within 9 months during 2013-2014 at Imam Reza medical center in Tabriz, Iran for identification of bacteria. The activity of various antimicrobial agents for 12 different antibiotics was determined with disk diffusion methods according to CLSI guideline (PadtanTeb) and MIC test carried out for imipenem, ciprofloxacin and amikacin antibiotics on samples. Out of the 61 clinical Acinetobacter baumanniiisolates collected, 59 (96.7%) were multi drug resistant (MDR). Respiratory tract specimens were the most common place of Acinetobacter isolation. To determine the disk diffusion agar method, the highest levels of antibiotic resistance were seen against imipenem, ceftazidime, ceftriaxon, and ciprofloxacin (99%). Colistin(89%), amikacin and tobramycin (50%) were the most effective antibiotics against Acinetobacter baumannii. MIC test among all samples shows that, 73.3% of factors have MIC ≥32 to imipenem, 93.3% of factors have MIC ≥ 32 tociprofloxacin and 38% of factors have MIC ≥ 256 to amikacin. Our results confirm the high prevalence of Acinetobacter baumannii resistant isolates and the ensuing therapeutic problems in Iran and determination of the resistance patterns of these bacteria according to MIC is necessary. It would be a good idea to consider surveillance of antibiotic usage and restriction of using broad-spectrum antibiotics before development of resistance to these agents.