Culture methods impact recovery of antibiotic resistant Enterococci including Enterococcus cecorum from pre- and post-harvest chicken.

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Culture methods impact recovery of antibiotic resistant Enterococci including Enterococcus cecorum from pre- and post-harvest chicken.

Lett Appl Microbiol. 2016 Dec 17;:

Authors: Suyemoto MM, Barnes H, Borst LB

Abstract
Pathogenic strains of Enterococcus cecorum (EC) expressing multidrug resistance have emerged. In National Antimicrobial Resistance Monitoring System (NARMS) data, EC is rarely recovered from chickens. Two NARMS methodologies (FDA, USDA) were compared with standard culture (SC) techniques for recovery of EC. NARMS methods failed to detect EC in 58 cecal samples, 20 chicken breast or 6 whole broiler samples. EC was recovered from 1 of 38 (2.6%) and 2 of 38 (5.2%) pre-harvest spinal lesions (USDA and FDA method respectively). In contrast, using SC method, EC was recovered from 44 of 53 (83%) cecal samples, all 38 (100%) spinal lesions, 14 of 20 (70%) chicken breast samples and all 3 spinal lesions identified in whole carcasses. Compared to other Enterococcus spp., EC isolates had a higher prevalence of resistance to macrolides. The NARMS methods significantly affected recovery of enterococcal species other than EC. When the post-harvest FDA method was applied to pre-harvest cecal samples, isolates of E. faecium were preferentially recovered. All 11 E. faecium isolates were multidrug resistant including resistance to penicillin, daptomycin, and linezolid. These findings confirm that current methodologies may not accurately identify the amount and range of antimicrobial resistance of enterococci from chicken sources. This article is protected by copyright. All rights reserved.

PMID: 27987523 [PubMed - as supplied by publisher]