Molecular Characterization Identifies Upstream Presence of ISAba1 to OXA Carbapenemase Genes in Carbapenem-Resistant Acinetobacter baumannii

Abstract

Background Evaluating the expression pattern of oxacillinases (OXA) carbapenemases is essential to understand the prevalence and spread of carbapenem resistance Acinetobacter baumannii. Objectives The aim of the study is to evaluate the presence of OXA carbapenemase genes and ISAba1 upstream to these genes in carbapenem-resistant A. baumannii clinical isolates. Material and Methods A. baumannii isolated from clinical samples were phenotypically identified and antibiotics sensitivity was performed. Multiplex polymerase chain reaction (PCR) was used to detect OXA51-like gene, OXA carbapenemases genes (OXA-23-like, OXA-24-like, and OXA-58-like), and ISAba1 in carbapenem-resistant isolates. Results Out of 55 Acinetobacter isolates, 54 were confirmed as A. baumannii by PCR. Bla OXA-23-like gene was observed in 51 isolates of A. baumannii and none of the isolates showed the presence of bla OXA-24-like and bla OXA-58-like genes. Presence of ISAba1 upstream to OXA-23-like gene, OXA-51-like gene, and both OXA-51-like/OXA-23-like genes was observed in 51, 7, and 4 A. baumannii isolates, respectively. Conclusion The genetic pattern of carbapenem-resistant A. baumannii isolated in this study was unique, which should be factored for clinical protocols to manage infections caused by emerging resistant strains of A. baumannii.