This study, the presence of 4 common beta-lactamase encoding genes including OXA-23, OXA-51, VIM and IMP was determined simultaneously by multiplex PCR, either directly with sputum samples or with purified DNA, giving results within 3-4 hours instead of 2 days compared to the culture method. Within 58 samples positive with Acinetobacter baumannii collected from the hospital, OXA-51 fragment was dominant (81%), whereas, VIM fragment was only identified in one sample (DNA and sputum samples) (). The antibiograms indicated for 19 samples were used to find correlation between genotype and resistance phenotype. | Studies of common antibiotic resistance-associated genes of Acinetobacter baumannii