On-farm sources of Campylobacter species in broiler chickens (Dr Agnes Agunos et al)

Agnes Agunos, Lisa Waddell L, David Legerand Eduardo Taboada

IMG_4649Dr Agnes Agunos (center in picture) is a Scientist working at the Public Health Agnency of Canada. She is engaged in antimicrobial drug resistance research programs and below is the highlight of one of the project’s findings.

In Canada, Campylobacter remains one of the leading causes of foodborne illness in people and is frequently associated with the consumption of undercooked chicken products and cross contamination from handling chicken meat contaminated with Campylobacter. Antimicrobial-resistant campylobacter are frequently isolated from broiler chickens worldwide and recently the Canadian Integrated Program for Antimicrobial Resistance Surveillance has raised a concern about the emergence of fluoroquinolone-resistance in Campylobacter from chicken samples from farm to fork in some Canadian regions . Infection of fluoroquinolone-resistant Campylobacter may limit treatment options for bacterial infections in people. The class of antimicrobials that flouroquinolone belongs to is considered critically important to human medicine and not approved for use in broiler chickens or any poultry species in Canada. We hypothesized that the emergence of flouroquinolone- resistant Campylobacter may be due to farm-level sources, thus we conducted a systematic review of literature (95 relevant articles) to better understand the dissemination and maintenance of Campylobacter in broiler chicken production. A systematic review aims to find and summarize all the evidence on a topic and is the best source of “what is known” for use in decision-making.

Our review identified various sources of Campylobacter that could contaminate the flock during the grow-out period. These sources were broadly categorized as:

1) broiler breeders via vertical/pseudovertical transfer,

2) other livestock and domestic animals on farm (multi-commodity),

3) humans (poultry workers, contracted services such as catchers and poor farm biosecurity protocols),

4) environment (presence of stagnant water , manure stored within the farm premise) and,

5) drinking water (e.g., untreated water, not cleaning water system between grow-out, and not sanitizing water lines).

Among these five categories, the most important source of contamination appears to be the barn and farm environment, particularly in barns that were improperly cleaned and disinfected, had insufficient downtime between flocks and poor biosecurity practices. Most studies did not provide antimicrobial resistance results; however, there is evidence that antimicrobial resistant Campylobacter from a treated flock can contaminate other flocks on the premises (multi-age farms) suggestive that antimicrobial use impacts the susceptibility of isolates circulating within a farm premise and potentially to other poultry operations using the same operational services (e.g., catching crew, transport trucks) and facilities (e.g., abattoir). As evidenced by molecular testing and tracing Campylobacter in a poultry production chain, transmission of Campylobacter and antimicrobial resistant Campylobacter from breeder flocks to their progenies potentially occurs. However routine culture techniques are not sensitive enough to isolate Campylobacter in samples originating from hatcheries (e.g., egg swabs, dead-in –shell) and hatched chicks, which would be better evidence of vertical transmission.

The relative importance of the various Campylobacter sources identified in the systematic review may vary across poultry producing regions and likely depend on their operational and management practices. For most Canadian producers, maintaining strict biosecurity protocols at the farm level will likely have the most impact on controlling the spread of Campylobacter within farms and throughout the broiler chicken sector. Producers and veterinarians should consider prudent antimicrobial use practices and strictly adhere to antimicrobial drug use regulations, which will protect the effectiveness of antimicrobials that are critically or highly important to human medicine.

For links to the paper and related reports

 

Posted in 2014 Publications, Research Stories.