Detection of blaOXA-58-like and blaOXA-23-like Genes among Carbapenem Resistant Acinetobacter baumanii strains in Benha University Hospital

Background: A. baumannii has now emerged as a leading cause of hospital and community-acquired infections. Multidrug resistant A. baumannii has been increasingly reported worldwide. Carbapenem Resistant A. baumannii (CRAB) is enlisted as number one in the critical priority of the “Global Priority Pathogen List” by WHO, 2017. A simple and useful molecular technique for identifying A. baumannii isolates is the identification of the blaOXA-like- carbapenemase gene by Polymerase Chain Reaction (PCR) method. Objectives: The aim of this study was to detect the prevalence of blaOXA23 like and blaOXA58 like genes among 25 carbapenem resistant A. baumannii isolates at Benha University Hospital. Methodology: Different clinical samples were cultured on CHROMagarTM Acinetobacter medium and identified to the species level by Vitek2 automated system. All A. baumannii strains were screened for carbapenem resistance by culture on CHROMagarTM with MDR supplement and CRAB was confirmed by Vitek2 system. PCR was used for BlaOXA 23 gene and blaOXA58 gene detection in A. baumannii strains. Results: 25(20.8%) out of 120 different samples were positive for Acinetobacter by culture on CHROMagarTM Acinetobacter media. all Acinetobacter isolated strains (100%) were identified as A. baumannii by vitek2 identification cards. All strains of A. baumannii were carbapenem resistant (CRAB) as they were resistant to Imipenem and Meropenem. Also, all strains were Multi Drug Resistant (MDR). Four (16%) strains of A. baumannii were sensitive to each of Tigecyclin and Trimethoprim/sulfamethoxazole. in this study out of 25 resistant strains, 23 A. baumannii strains had carbapenem resistance genes (all had blaOXA23 and one of them had both blaOXA23 and blaOXA58) as diagnosed by PCR. Conclusion: PCR of the CRAB showed that blaOXA-23 gene had higher rate (92%) than blaOXA-58 gene (4%) in A. baumannii clinical isolates. Tigecycline can be considered a good therapeutic option due to the presence of some sensitive CRAB strains.