Emergence of carbapenem-resistant Acinetobacter baumannii harboring the OXA-23 carbapenemase in intensive care units of Egyptian hospitals

Abstract

Healthcare-associated infections are a worldwide threat to hospitalized patients, especially those in intensive care units. The prevalence of these infections in Egypt, and their antimicrobial resistance patterns and mechanisms, were investigated in this study. A total of 547 cases of healthcare-associated infections were investigated. Causative agents were identified and antimicrobial susceptibility determined. Carbapenem-resistant Acinetobacter baumannii isolates were further investigated for their resistance mechanism via the modified Hodge test, inhibitor-potentiated disk diffusion test, synergy with carbonyl cyanide chlorophenylhydrazone, and PCR. Moreover, clonal linkage was examined via enterobacterial repetitive intergenic consensus (ERIC)-PCR. Klebsiella spp was the most prevalent species in the isolates examined (217; 40%). Although A. baumannii represented only 10% of the total isolates, it showed the highest percentage of carbapenem resistance (74%). PCR showed that 100% of the resistant isolates carried both blaOXA-51 and blaOXA-23 genes, 85% carried the class 1 integrase genes, and only 2.5% carried metallo-beta-lactamase (blaVIM). ERIC-PCR indicated that isolates from different hospitals were genetically linked. These findings represent the first report of the alarming spread of OXA-23 carbapenemase in A. baumannii in Egyptian intensive care units. The spread of such strains has serious health consequences and requires the application of strict infection control measures.