Acinetobacter baumannii (A. baumannii) is recognized as a major pathogen causing nosocomial infections, particularly in patients admitted to intensive care units (ICU), and many widespread strains are resistant to almost all antibiotics currently in use. Carbapenemases belonging to molecular class D (OXA enzymes) have emerged globally as the main mechanism responsible for this resistance. This work aimed at detecting the spread of OXA carbapenemases in A. baumannii in ICU patients and to identify the susceptibility patterns of strains to polymyxin E (colistin), polymyxin B, and tigecycline as a promising option for treatment. Twenty seven clinical isolates of A. baumannii, collected from Alexandria Main University Hospital, were included in this study.  A. baumannii was isolated from different clinical samples from ICU patients. All 27 isolates were subjected to complete identification and antimicrobial susceptibility testing. The identified carbapenem resistant A. baumannii strains were tested for the presence of bla _OXA-23, bla_OXA-24, bla_OXA-58 and bla_OXA-51 genes using multiplex PCR assay. Colistin and polymyxin B were found to be active upon the majority of identified resistant A. baumannii strains, where around 70% of the strains were sensitive to both of them, while tigecycline was found to be more effective as 92.5% of strains were sensitive to it. Resistance to carbapenems was mediated by both OXA-51 (100%) and OXA-23 (92.5%)  for the tested A. baumannii strains.