AUTHOR=Chalhoub Hussein , Kampmeier Stefanie , Kahl Barbara C. , Van Bambeke Françoise 

TITLE=Role of Efflux in Antibiotic Resistance of Achromobacter xylosoxidans and Achromobacter insuavis Isolates From Patients With Cystic Fibrosis

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.762307

DOI=10.3389/fmicb.2022.762307

ISSN=1664-302X

ABSTRACT=<p><italic>Achromobacter</italic> genus (including <italic>Achromobacter xylosoxidans</italic>, the most prevalent <italic>Achromobacter</italic> species in patients with cystic fibrosis) is poorly susceptible to most conventional antibiotics. Contribution of efflux by AxyABM, AxyXY-OprZ, and AxyEF-OprN and of target mutations were studied in clinical isolates of <italic>A. xylosoxidans</italic> and <italic>Achromobacter insuavis.</italic> Forty-one isolates longitudinally collected from 21 patients with CF were studied by whole-genome sequencing (WGS)-typing, determination of minimum inhibitory concentrations (MICs) of β-lactams, aminoglycosides, colistin, azithromycin, ciprofloxacin, chloramphenicol, and doxycycline, and expression (quantitative RT-PCR) and function (measure of the uptake of a fluorescent substrate) of efflux pumps. WGS-based typing resulted in 10 clusters comprising 2 or 3 isolates and 20 singletons. The efflux activity was high in strains with elevated MICs for amikacin or azithromycin. This work sheds a new light on the impact of efflux and target mutations in resistance of <italic>Achromobacter</italic> to several drugs.</p>