AUTHOR=Haenni Marisa , Bour Maxime , Châtre Pierre , Madec Jean-Yves , Plésiat Patrick , Jeannot Katy 

TITLE=Resistance of Animal Strains of Pseudomonas aeruginosa to Carbapenems

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01847

DOI=10.3389/fmicb.2017.01847

ISSN=1664-302X

ABSTRACT=<p>Carbapenems are major antibiotics reserved to human medicine. This study aimed to investigate the mechanisms of carbapenem resistance of a selection of <italic>Pseudomonas aeruginosa</italic> veterinary strains from the French network Resapath. Thirty (5.7%) imipenem and/or meropenem non-susceptible <italic>P. aeruginosa</italic> of canine (<italic>n</italic> = 24), feline (<italic>n</italic> = 5), or bovine (<italic>n</italic> = 1) origin were identified in a large collection of 527 veterinary strains gathered by the Resapath. These resistant isolates belonged to 25 MultiLocus Sequence Types (MLST), of which 17 (68%) are shared with clinical (human) strains, such as high risk clones ST233 and ST395. Interestingly, none of the veterinary strains produced a carbapenemase, and only six of them (20%) harbored deletions or insertion sequence (IS) disrupting the porin OprD gene. The remaining 24 strains contained mutations or IS in various loci resulting in down-regulation of gene <italic>oprD</italic> coupled with upregulation of efflux system CzcCBA (<italic>n</italic> = 3; activation of sensor kinase CzcS ± CopS), MexEF-OprN (<italic>n</italic> = 4; alteration of oxido reductase MexS), MexXY (<italic>n</italic> = 8; activation of two-component system ParRS), or MexAB-OprM (<italic>n</italic> = 12; alteration of regulator MexR, NalC ± NalD). Two efflux pumps were co-produced simultaneously in three mutants. Finally, in 11 out of 12 strains displaying an intact porin OprD, derepression of MexAB-OprM accounted for a decreased susceptibility to meropenem relative to imipenem. Though not treated by carbapenems, animals thus represent a reservoir of multidrug resistant <italic>P. aeruginosa</italic> strains potentially able to contaminate fragile outpatients.</p>