AUTHOR=Charretier Yannick , Köhler Thilo , Cecchini Tiphaine , Bardet Chloé , Cherkaoui Abdessalam , Llanes Catherine , Bogaerts Pierre , Chatellier Sonia , Charrier Jean-Philippe , Schrenzel Jacques 

TITLE=Label-free SRM-based relative quantification of antibiotic resistance mechanisms in Pseudomonas aeruginosa clinical isolates

JOURNAL=Frontiers in Microbiology

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2015.00081

DOI=10.3389/fmicb.2015.00081

ISSN=1664-302X

ABSTRACT=<p>Both acquired and intrinsic mechanisms play a crucial role in <italic>Pseudomonas aeruginosa</italic> antibiotic resistance. Many clinically relevant resistance mechanisms result from changes in gene expression, namely multidrug efflux pump overproduction, AmpC β-lactamase induction or derepression, and inactivation or repression of the carbapenem-specific porin OprD. Changes in gene expression are usually assessed using reverse-transcription quantitative real-time PCR (RT-qPCR) assays. Here, we evaluated label-free Selected Reaction Monitoring (SRM)-based mass spectrometry to directly quantify proteins involved in antibiotic resistance. We evaluated the label-free SRM using a defined set of <italic>P. aeruginosa</italic> isolates with known resistance mechanisms and compared it with RT-qPCR. Referring to efflux systems, we found a more robust relative quantification of antibiotic resistance mechanisms by SRM than RT-qPCR. The SRM-based approach was applied to a set of clinical <italic>P. aeruginosa</italic> isolates to detect antibiotic resistance proteins. This multiplexed SRM-based approach is a rapid and reliable method for the simultaneous detection and quantification of resistance mechanisms and we demonstrate its relevance for antibiotic resistance prediction.</p>