Contributionof efflux pumps to carbapenem resistant acinetobacter baumannii in Egypt / Hadeer Ezzat Abdelnabi ; Supervised Hamdallah H. Zedan , Neveen M. Saleh

Thesis (M.Sc.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

Acinetobacter baumannii (A.baumannii) is a Gram-negative coccobacillus, constitutes a major public health problem due to its propensity to develop resistance to almost all drugs.Carbapenem antibiotics have been widely used for treating A. baumannii infections. However, the emergence of resistantA.baumanniistrains has been increasingly reported and is often associated with high mortality rates and a substantial increase in hospitalization costs. Moreover, as carbapenem-resistant A. baumannii (CRAB) also presents resistance to other antimicrobial classes, and alternative therapeutic approaches need to be explored. This study is designed to detect the overexpression of resistance-nodulation (RND) efflux pumps genes in clinical isolates of A.baumannii, and its correlation to multidrug resistance isolates, in particular the carbapenem resistance Acinetobacter (CRAB). Moreover, to restore the activity of carbapenem antibiotics, different efflux pump inhibitors (EPIs) were evaluated. A total of 150 A.baumanniiisolates were collected from ICU patients of three Egyptian hospitals and presumptively identified using the phenotypic and biochemical examination, further confirmed by detection ofblaOXA -51 like gene using conventional PCR. Antimicrobial susceptibility to 15 antibiotics of different classes was determined according to CLSI guidelines, indicating the spread of MDR in all clinical A.baumannii strains. The highest resistance rates were observed against ceftriaxone, amoxicillin/sulbactam, and imipenem (IMP) 100, 97, & 75%, respectively. Minimal inhibitory concentrations (MIC) of imipenem were evaluated for selected CRAB strains, MIC values range from 8-1024og/ml

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