Resistance, heteroresistance, and fitness costs drive colistin treatment failure during <i>Acinetobacter baumannii</i> pneumonia.

ABSTRACT: Acinetobacter baumannii is an Enterococcus, Staphylococcus, Klebsiella, Acinetobacter, Pseudomonas, and Enterobacter species (ESKAPE) pathogen linked to healthcare-associated diseases. Due to evolved resistance, last-resort antibiotics such as the lipooligosaccharide (LOS)-targeting colistin are increasingly used to treat multidrug-resistant isolates. To track the evolution of colistin resistance within a host, we performed sequential oropharyngeal infections in immunocompetent or immune-depleted mice in the presence of inhaled colistin. Both resistant and heteroresistant A. baumannii strains emerged with pmrB mutations that efficiently competed with the susceptible parent in the presence of colistin. These pmrB mutants

SUBMITTER: Hernandez-Bird J 

PROVIDER: S-EPMC12773716 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature