en Anti-microbial agents, resistance and treatment protocols Anti-microbial agents, resistance and treatment protocols Original article Original article <p dir="ltr"><strong>Introduction:</strong> <em>Acinetobacter baumannii</em>, a known causative agent of nosocomial infections, is one of the highly antibiotic-resistant gram-negative bacilli<em>. </em>Carbapenem-resistant <em>Acinetobacter</em> isolates are increasingly reported worldwide. Carbapenems such as imipenem and meropenem are efficient antimicrobial agents commonly used for the treatment of infections caused by multi- resistant <em>A. baumannii</em> strains. Some reports indicate treatment failure due to antibiotic resistant <em>A. baumannii</em> strains. The aim of this study was to determine antibiotic resistance pattern and prevalence carbapenemase production in <em>A. baumannii </em>isolates. <strong>Method: </strong>A total of 100 <em>A. baumannii</em> isolates were identified from clinical specimens by standard chemical tests. The samples were collected from the patients hospitalized in two teaching hospitals of Ahvaz, southwestern of Iran. The susceptibility of isolates to different antibiotics was determined by the disk diffusion method based on Clinical Laboratory Standards Institute (CLSI) direction. The Modified Hodge Test (MHT) was performed for detection of carbapenemase - producing <em>A. baumannii</em> isolates.<strong> Results:</strong> The isolates showed the highest resistance to ciprofloxacin (98%). The resistance rate to cefotaxime, ceftazidime, and piperacillin was 97%, gentamicin, amikacin, and meropenem 96%, imipenem 95%, cefepime 93%, and tetracycline 60%. Most of the isolates (99%) were sensitive to colistin. Among the100 <em>A. baumannii</em> isolates, 53 (53%) were positive for carbapenemase production by MHT. <strong>Conclusion: </strong>This study emphasizes dissemination of carbapenem resistant <em>A. baumannii</em> strains. Our study also showed that the MHT has an excellent sensitivity for detecting carbapenemase - producing <em>A. baumannii </em>isolates.</p> Acinetobacter baumannii, Antibiotic Resistance, Carbapenemase, Modified Hodge Test 163 166 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-90-1&slc_lang=en&sid=1 Mojtaba Moosavian moosavian_m@yahoo.com No Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Nasim Shams nasim7shams@gmail.com Yes Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Mehrandokht Sirous mehrandokht.sirous@gmail.com No Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran