Prevalence and Genetic Basis of Antimicrobial Resistance in Non-aureusStaphylococci Isolated from Canadian Dairy Herds

Nobrega, Diego B; Naushad, Sohail; Naqvi, S Ali; Condas, Larissa A Z; Saini, Vineet; Kastelic, John P; Luby, Christopher; De Buck, Jeroen; Barkema, Herman W

Prevalence and Genetic Basis of Antimicrobial Resistance in Non-aureusStaphylococci Isolated from Canadian Dairy Herds

dc.contributor.author	Nobrega, Diego B
dc.contributor.author	Naushad, Sohail
dc.contributor.author	Naqvi, S Ali
dc.contributor.author	Condas, Larissa A Z
dc.contributor.author	Saini, Vineet
dc.contributor.author	Kastelic, John P
dc.contributor.author	Luby, Christopher
dc.contributor.author	De Buck, Jeroen
dc.contributor.author	Barkema, Herman W
dc.date.accessioned	2018-03-07T16:28:15Z
dc.date.available	2018-03-07T16:28:15Z
dc.date.issued	2018-01
dc.description.abstract	Emergence and spread of antimicrobial resistance is a major concern for the dairy industry worldwide. Objectives were to determine: (1) phenotypic and genotypic prevalence of drug-specific resistance for 25 species of non-aureus staphylococci, and (2) associations between presence of resistance determinants and antimicrobial resistance. Broth micro-dilution was used to determine resistance profiles for 1,702 isolates from 89 dairy herds. Additionally, 405 isolates were sequenced to screen for resistance determinants. Antimicrobial resistance was clearly species-dependent. Resistance to quinupristin/dalfopristin was common inStaphylococcus gallinarum(prevalence of 98%), whereasS. cohniiandS. arlettaewere frequently resistant to erythromycin (prevalence of 63 and 100%, respectively). Prevalence of resistance was 10% against β-lactams and tetracyclines. In contrast, resistance to antimicrobials critically important for human medicine, namely vancomycin, fluoroquinolones, linezolid and daptomycin, was uncommon (< 1%). Genes encoding multidrug-resistance efflux pumps and resistance-associated residues in deducted amino acid sequences of thefolPgene were the most frequent mechanisms of resistance, regardless of species. The estimated prevalence of themecAgene was 17% forS. epidermidis. Several genes, includingblaZ, mecA, fexA, erm, mphC, msrA, andtetwere associated with drug-specific resistance, whereas other elements were not. There were specific residues ingyrBfor all isolates of species intrinsically resistant to novobiocin. This study provided consensus protein sequences of key elements previously associated with resistance for 25 species of non-aureusstaphylococci from dairy cattle. These results will be important for evaluating effects of interventions in antimicrobial use in Canadian dairy herds.	en_US
dc.description.sponsorship	Sponsored by the Open Access Authors Fund	en_US
dc.identifier.citation	Nobrega, D. B., Naushad, S., Naqvi, S. A., Condas, L. A., Saini, V., Kastelic, J. P., ... & Barkema, H. W. (2018). Prevalence and Genetic Basis of Antimicrobial Resistance in Non-aureus Staphylococci Isolated from Canadian Dairy Herds. Frontiers in Microbiology, 9, 256.	en_US
dc.identifier.doi	http://dx.doi.org/10.3389/fmicb.2018.00256	en_US
dc.identifier.uri	http://hdl.handle.net/1880/106422
dc.language.iso	en	en_US
dc.publisher	Frontiers in Microbiology	en_US
dc.publisher.faculty	Veterinary Medicine	en_US
dc.publisher.hasversion	Pre-print	en_US
dc.publisher.institution	University of Calgary	en_US
dc.rights	Unless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.	en_US
dc.rights.uri	https://creativecommons.org/licenses/by/4.0	en_US
dc.title	Prevalence and Genetic Basis of Antimicrobial Resistance in Non-aureusStaphylococci Isolated from Canadian Dairy Herds	en_US
dc.type	journal article