The nosocomial infections, caused by multi-drug resistant bacteria, are the most important cause of mortality throughout the world. One important mechanism against beta-lactam antibiotics is the production of beta-lactamases.Enterobacteriaceae and nonfermentative bacteria, like Pseudomonas aeruginosa and Acinetobacter baumannnii mayproduce these enzymes. Currently, there is no vaccine to prevent the infections caused by b-lactamase-producing bacteria. Consequently, it is necessary to identify b-lactamaseproducing bacteria by phenotypic and molecular methods.

The emergence and spread of carbapenemase-producing bacteria, that hydolyze most β-lactams, including carbapenems, are a major concern of public health system worldwide, particularly in the Middle East area. Since the plasmids harboring resistancegenes could be spread across other bacterial populations, detection of carbapenemase-producing organisms has becomemore problematic. These organisms produce different types of enzymes including the most prevalent types including KPC, VIM, IMP, NDM, and OXA-48. Carbapenemase producers are mostly identified among Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. This study reviewed almost all papers, which conducted inthe Middle East. In order to decrease the spread of resistance, the regional cooperation has been emphasized by the MiddleEast countries. The highest resistance, which is mediated by KPC has been observed in Afghanistan, Saudi Arabia and Jordanfollowed by NDM in Pakistan and OXA in Turkey and Pakistan. It is important to mention that the spread of these types havebeen reported sporadically in the other countries of this area. This review described the widespread carbapenemases in theMiddle East area, which have been identified in an alarming rate.

Introduction: Acinetobacter baumannii, a known causative agent of nosocomial infections, is one of the highly antibiotic-resistant gram-negative bacilli. Carbapenem-resistant Acinetobacter 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 A. baumannii strains. Some reports indicate treatment failure due to antibiotic resistant A. baumannii strains. The aim of this study was to determine antibiotic resistance pattern and prevalence carbapenemase production in A. baumannii isolates. Method: A total of 100 A. baumannii 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 A. baumannii isolates. Results: 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 A. baumannii isolates, 53 (53%) were positive for carbapenemase production by MHT. Conclusion: This study emphasizes dissemination of carbapenem resistant A. baumannii strains. Our study also showed that the MHT has an excellent sensitivity for detecting carbapenemase - producing A. baumannii isolates.