Open AccessExpression of the MexXY Aminoglycoside Efflux Pump and Presence of an Aminoglycoside-Modifying Enzyme in Clinical Pseudomonas aeruginosa Isolates Are Highly Correlated
Author(s) -
Alexander Seupt,
Monika Schniederjans,
Jürgen Tomasch,
Susanne Häußler
Publication year - 2020
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.01166-20
Subject(s) - aminoglycoside , pseudomonas aeruginosa , efflux , microbiology and biotechnology , biology , pseudomonadaceae , antibiotics , bacteria , genetics
The impact of MexXY efflux pump expression on aminoglycoside resistance in clinical Pseudomonas aeruginosa isolates has been debated. In this study, we found that, in general, elevated mexXY gene expression levels in clinical P. aeruginosa isolates confer to slight increases in aminoglycoside MIC levels; however, those levels rarely lead to clinically relevant resistance phenotypes. The main driver of resistance in the clinical isolates studied here was the acquisition of aminoglycoside-modifying enzymes (AMEs). Nevertheless, acquisition of an AME was strongly associated with mexY overexpression. In line with this observation, we demonstrate that the introduction of a gentamicin acetyltransferase confers to full gentamicin resistance levels in a P. aeruginosa type strain only if the MexXY efflux pump was active. We discuss that increased mexXY activity in clinical AME-harboring P. aeruginosa isolates might affect ion fluxes at the bacterial cell membrane and thus might play a role in the establishment of enhanced fitness that extends beyond aminoglycoside resistance.