Phenotypic and genotypic analysis of antibiotic resistance in Acinetobacter spp. isolates in Baghdad, Iraq

Background: The Acinetobacter genus is a gram-negative coccobacillus initially considered to be an opportunistic pathogen, which plays a vital role as a major cause of healthcare-associated infections. This study aimed to analysis the resistance profiles of Acinetobacter spp. isolates against a range of antibiotics by phenotype and genotype Characteristics. Methods: This descriptive study was conducted on 60 isolates of Acinetobacter species (44 Acinetobacter baumannii and 16 Acinetobacter complex) collected from different clinical samples in many hospitals in Baghdad city. Standard microbiological tests were done to identify the isolates. Susceptibility and resistance pattern to various antibiotics was detected by the disk diffusion method and were confirmed using the VITEK-2 system. Phenotypic tests were done to determine Acinetobacter spp. The polymerase chain reaction (PCR) method determined the presence of genes coding for antibiotic resistance, such as bla OXA-51, qnrA, qnrB, and ERIC genes. Results: Out of 60 isolates, the highest rate of resistance was observed for piperacillin (90%). The resistance rate for cefepime, ciprofloxacin, gentamicin, piperacillin-tazobactam, and meropenem was 78.3%, 80%, 85%, 83.3%, 75%, respectively. The distribution of the bla OXA-51, qnrA, and qnrB was 73.3%, 4.5%, and 100%, respectively. Conclusion: High prevalence of oxa-51 and qnrB genes among Acinetobacter spp. isolated strains in this study indicate the important role of these genes in multidrug resistance in this bacterium. The ERIC gene was used to assess the genetic diversity of the isolates.