Effet de l'arrêt du ceftiofur et son remplacement par la lincomycine-spectinomycine sur les gènes de bêta-lactamase à spectre étendu ESBL/AmpC et sur la multirésistance chez les Escherichia coli provenant d'une chaîne de production aviaire pyramidale au Canada
Ceftiofur, a cephalosporin antimicrobial, has been used systematically in Canadian hatcheries for many years to prevent early mortality in chicks leading to a high prevalence of cephalosporin resistance in Escherichia coli in chickens Preventive use of ceftiofur in hatcheries stopped in 2014. We examined the effect of ceftiofur, complete antimicrobial cessation in hatchery and replacement with lincomycin-spectinomycin on the proportion of E. coli positive sample for extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase related genes, and on the multidrug resistance profiles of ESBL/AmpC positive E. coli in broilers and their associated breeders, at one year post-cessation. For indicator E. coli from non-enriched ceftriaxone media, a significant decrease post-cessation in the proportion of samples harboring E. coli isolates positive for blaCMY-2 and/or blaCTX-M was observed. In contrast, following enrichment in medium containing ceftriaxone (1mg/L) to facilitate recovery of ESBL/AmpC β-lactamase producing E. coli colonies, both pre- and post-cessation, 99% of the samples harbored E. coli positive for blaCMY-2 or blaCTX-M. Flocks receiving lincomycin-spectinomycin after cessation of ceftiofur showed a significantly greater non-susceptibility to aminoglycoside, folate inhibitor, phenicol, tetracycline and possible extensively drug resistant E. coli isolates compared to those that received ceftiofur or no antimicrobial at hatchery. This study clearly demonstrates an initial decrease in ESBL/AmpC positive E. coli following the cessation of ceftiofur in hatchery but an increase in multidrug resistant to different antimicrobial class tested in E. coli following replacement with lincomycin-spectinomycin.
ceftiofur blaCMY-2 blaCTX-M cessation chicken lincomycin-spectinomycin antimicrobial resistance