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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.