Vol.5 No.1 – 10 : Clonal Diversity and High Prevalence of Oxa-23 among Carbapenem Resistant Acinetobacter baumannii Isolates in Egypt

By : Nevine Fam¹, Doaa Gamal¹, *Dalia Salem¹, Heba Dahroug¹, Reham M. Wasfy¹, Myriam M. Morcos².

¹Department of Microbiology, Theodor Bilharz Research Institute (TBRI), Giza, Egypt.

²Naval Medical Research Laboratories (NAMRU-3). Cairo, Egypt.

Abstract

Background and Aim: Carbapenem-resistant Acinetobacter baumannii (CRAB) is becoming a global threat especially to hospitalized patients. We aimed to address the magnitude of CRAB causing healthcare-associated infections in patients admitted to a tertiary healthcare hospital in Egypt and to study their genetic and epidemiologic diversity. Materials and Methods: Twenty-six CRAB isolates representing 48% of all Acinetobacter baumannii (A. baumannii) isolated in the study period were identified by microbiological culture methods and verified by presence of bla-oxa₅₁. Antimicrobial susceptibility was tested by disc diffusion and MIC was determined by VITEK2 compact system. Phenotypic expression of metallo-β-lactamases (MBLs) was determined by MBL IP/IPI E-test. Carbapenemase encoding genes were identified by PCR and clonal relatedness was studied by pulsed field gel electrophoresis (PFGE) using Apa1 and PulseNet protocol. Results: All A. baumannii isolates were multi-drug resistant (MDR). Colistin and minocycline showed the highest sensitivities of 100% and 61.1%respectively. MBLs were phenotypically detected in 20/26 (76.9%) of the isolates while bla_OXA-23-like was the main carbapenem resistance gene recorded in 61.5% followed by bla_NDM-1-like (26.9%) and bla_GES-like (7.7%).  PFGE typing showed high diversity as most of the isolates were < 80% similar. Conclusion: Carbapenem resistance among A. baumannii isolates is increasing dramatically in our geographic region. Bla_OXA-23-likeis the most common gene in CRAB isolates in our hospital setting. In addition, bla_NDM-1-like and bla_GES-like harboring A. baumannii isolates are exhibiting a considerable spread in hospital environment in Egypt. The clonal diversity of our CRAB isolates suggests that it could be due to horizontal dissemination of mobile genetic elements rather than propagation of a certain clone.

Clonal-Diversity-and-High-Prevalence-of-Oxa-23-among-Carbapenem-Resistant-Acinetobacter-baumannii-Isolates-in-Egypt

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