Acquired colistin resistance among gram negative bacilliisolated from patients admitted at Cairo University Hospitals / Karim Abdo Abdo Ibrahim ; Supervised Ashraf E. Sorour , Asmaa Sayed Hegab

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

Polymyxins, antibiotics that were mostly abandoned a few decades ago because of toxicity concerns, are ultimately considered as a last-line therapy to treat infections caused by multidrug resistant gramnegative bacilli.Polymyxin B and polymyxin E (colistin) are the two polymyxins used in clinical practice. Most of the re-introduction of polymyxins during the last few years is attributed to colistin.Resistance to colistin, mediated by chromosomal mutations and more recently, by plasmid{u2010}borne mcr genes, is increasingly being reported in different countries.In the present study, a total of 180 different clinical specimens were collected from the patients admitted at different departments of Cairo University Hospitals until 115 gram negative bacilli isolates were isolated. We attempted to determine the prevalence of colistin resistance among thegram negative bacilli isolates using the broth microdilution method to determine colistin minimum inhibitory concentration (MIC). We also attempted to compare colistin resistance among different gram negative bacilli spp. and to study the antibiotic susceptibility of differentgram negative bacilli isolates. The results obtained from this study showed that the prevalence of colistin resistance among different gram negative bacilli isolates was as follows: 12.5% among E.coli (3/24), 9.5% among Klebsiella spp. (4/42), 13.8% among Pseudomonas spp.(4/29) and 5.0% among Acinetobacter spp. (1/20). The overall colistin resistance rate among Enterobacteriaceaewas 10.6% (7/66) while the overall colistin resistance rate among gram negative bacilli was 10.4% (12/115)

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