Promoters of Colistin Resistance in Acinetobacter baumannii Infections

• Published in: Microbial drug resistance (Larchmont, N.Y.) Vol. 25; no. 7; p. 997
• Main Authors: Nurtop, Elif, Bayındır Bilman, Fulya, Menekse, Sirin, Kurt Azap, Ozlem, Gönen, Mehmet, Ergonul, Onder, Can, Fusun
• Format: Journal Article
• Language: English
• Published: United States 01.09.2019
• Subjects: Acinetobacter baumannii - drug effects; Acinetobacter baumannii - genetics; Acinetobacter Infections - drug therapy; Acinetobacter Infections - microbiology; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - pharmacology; Bacterial Proteins - genetics; beta-Lactamases - genetics; Colistin - pharmacology; Drug Resistance, Bacterial - drug effects; Drug Resistance, Bacterial - genetics; Female; Humans; Male; Microbial Sensitivity Tests - methods; Middle Aged; Mutation - genetics; Promoter Regions, Genetic - genetics; Transcription Factors - genetics; A. baumannii; colistin; resistance
• ISSN: 1931-8448
• DOI: 10.1089/mdr.2018.0396

We aimed to describe the mechanisms of colistin resistance in . Twenty-nine patients diagnosed with colistin-resistant infection were included to the study. The mutations in , , , and genes, expression of , carbapenemases, and positivity were studied. Twenty-seven (93%) of the patients received IV colistin therapy during their stay, and the case fatality rate was 45%. All mutations in and were found to be accompanied with a mutation in . The most common mutations were I42V and L150F in (65%), E117K in (65%), and A138T in (58.6%). The colistin minimum inhibitory concentrations (MICs) of the isolates having any of these four mutations were higher than the isolates with no mutations (  < 0.001). The two most common mutations in (I42V and L150F) were found to be associated with higher expressions of and and higher colistin MIC values (  = 0.010 and 0.031). All isolates were positive. Coexistence of the mutation along with mutations in indicates synergistic function of these genes in development of colistin resistance in .