Antimicrobial use surveillance in broiler chicken flocks in Canada, 2013-2015

Abstract

There is a paucity of data on the reason for and the quantity of antimicrobials used in broiler chickens in Canada. To address this, the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) implemented surveillance of antimicrobial use (AMU) and antimicrobial resistance (AMR) in broiler chicken flocks in 2013. Shortly after this (2014), the poultry industry banned the preventive use of ceftiofur in broiler chickens. The objectives of this analysis were to describe antimicrobial use (AMU) in Canadian broiler chickens between 2013 and 2015 (n = 378 flocks), compare these results to other animal species in Canada, to highlight the utility of farm surveillance data to evaluate the impact of a policy change, and to explore how different antimicrobial use metrics might affect data interpretation and communication. The surveillance data indicated that the poultry industry policy resulted in lower antimicrobial use and resistance, and they successfully captured information on when, where, why, and how much antimicrobials were being used. The majority of antimicrobials were administered via the feed (95%). The relative frequency of antimicrobial classes used in broiler chickens differed from those used in swine or in food animal production in general. Coccidiostats were the most frequently used antimicrobial classes (53% of total kg). Excluding coccidiostats, the top three most frequently used antimicrobial classes were bacitracin (53% of flocks), virginiamycin (25%) and avilamycin (21%), mainly used for the prevention of necrotic enteritis. Depending on the AMU metric utilized, the relative rankings of the top antimicrobials changed; hence the choice of the AMU metric is an important consideration for any AMU reporting. When using milligrams/Population Correction Unit (mg/PCU) the top three antimicrobial classes used were bacitracins (76 mg/PCU), trimethoprim-sulfonamides (24 mg/PCU), and penicillins (15 mg/PCU), whereas when using a number of Defined Daily Doses in animals using Canadian standards /1,000 chicken-days at risk (nDDDvetCA/1,000 CD) the ranking was bacitracins (223 nDDDvetCA/1,000 CD), streptogramins (118 nDDDvetCA/1,000 CD), and trimethoprim-sulfonamides (87 nDDDvetCA/1,000 CD). The median animal treatment days in feed for one cycle (ATD/cycle) during the three-year study were 34 ATD/cycle; this was equal to the mean age of the flocks at pre-harvest sampling day (days at risk), indicating that the studied flocks except those that were raised without antibiotics and organic, were fed with medicated rations throughout the observation period. Overall, more than half (59%) of antimicrobials used in broiler chickens were in classes not used in human medicine, such as ionophores and chemical coccidiostats aimed to prevent coccidiosis. Compared to grower-finisher pigs and in production animal species (national sales data), the mg/PCU of antimicrobials used in broiler chickens was relatively lower. The findings of this paper highlighted the importance of farm-level AMU surveillance in mea...

Effect of ceftiofur cessation and substitution with lincomycin-spectinomycin on extended-spectrum-beta-lactamase/AmpC genes and multidrug resistance in E. coli from a Canadian broiler production pyramid

“…In a study of E. coli isolates from clinical cases of colibacillosis in chickens in Québec, Canada, Chalmers et al (6) demonstrated that the use of spectinomycin could increase co-selection. Indeed, the presence of resistance to spectinomycin ( aac(3)-VI gene) and gentamicin ( aadA) , an antimicrobial that is no longer routinely used in Canadian poultry, were strongly associated statistically and located on a modified class 1 integron. These authors also demonstrated that the use of spectinomycin did not seem to select cephalosporin resistant E. coli or APEC.…”

“…These authors also demonstrated that the use of spectinomycin did not seem to select cephalosporin resistant E. coli or APEC. The aac(3)-VI and bla CMY-2 genes were negatively associated, but when present together, were generally located on the same plasmids (6). An increase of bacteria with co-selection of antimicrobial resistance and greater MDR would thus be expected with the use of lincomycin-spectinomycin and could allow the emergence of a bacterial flora that contains more MDR and, possibly, XDR bacteria.…”

“…One of the most important causes of early mortality in broiler chick is omphalitis, mostly caused by avian pathogenic E. coli (APEC), a subgroup of extra-intestinal pathogenic E. coli (ExPEC) (1, 2). Ceftiofur, a third generation cephalosporin antimicrobial, has been administered for over 15 years either in ovo or by subcutaneous injection at the hatchery, in order to reduce early chick mortality in many countries (3) Consequently, an increased prevalence of extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase producing Escherichia coli has been reported worldwide (4-7), resulting in an increased extended spectrum cephalosporin resistance in the broiler poultry chain production. This is a public health concern due to co-resistance with other extended spectrum cephalosporins, such as ceftriaxone and cephamycin, antimicrobials which are used widely in human medicine (8, 9).…”

“…In Canada in 2014, the poultry industry eliminated the preventive use of Ceftiofur in hatcheries for the second time (3). Following the first cessation in 2005, a decline in the prevalence of cephalosporin-resistant Salmonella Heidelberg isolates in chicken meat was observed, although the effect on prevalence of resistance in E. coli was not clear (9).…”

“…A decrease in the prevalence of Salmonella harboring bla CMY-2 in chicken meat was also observed in Japan in the same years (14). In Canada, whereas some hatcheries completely stopped using antimicrobials following the cessation of ceftiofur (15), other hatcheries replaced it with lincomycin-spectinomycin (3, 6).…”