Can probiotics combat pathogens?

Probiotics could form an alternative to antimicrobials, according to researchers from Ontario Veterinary College. They have been studying the use of probiotics to combat pathogens such as Salmonella, Campylobacter jejuni and Clostridium perfringens in poultry.

Dr Shayan Sharif, a professor at Ontario Veterinary College at the University of Guelph, has previously researched probiotics to combat Salmonella and is now focusing on Campylobacter jejuni.

“We’ve clearly shown by using combinations of different lactobacilli or lactic acid-producing bacteria, we can reduce colonisation or burden of Salmonella in poultry quite significantly,” explained Dr Sharif.

Campylobacter jejuni may be more complicated, however, as it is carried within a chicken’s intestine throughout their lifetime but often fails to show any symptoms. This could be detrimental to humans consuming undercooked poultry, as this type of bacteria is the main cause of human enteritis or foodborne illness.

Campylobacter has proven to be difficult to control using vaccination, biosecurity and antibiotics, and both Campylobacter jejeuni and Salmonella can harbour and transfer antimicrobial resistance genes.

Dr Sharif is examining the effect of probiotics on the overall health, welfare and production of poultry, with the aim of determining if probiotics improve the immune system of the chickens.

“We want to know if animals as a whole are healthier, if they produce more, if there is better weight gain and if their feed conversion ratio would be better compared to chickens receiving conventional diets.”

Next, Dr Sharif and his colleagues aim to study Clostridium perfringens, which can cause necrotic enteritis — an inflammation of the intestine in poultry.

Necrotic enteritis usually works with another microorganism called Eimeria, or coccidia, which often predisposes the animal to the pathogenic effects of Clostridium perfringens. Controlling coccidia is possible using antimicrobials, but without treatment there could be a surge in coccidiosis and necrotic enteritis, both of which would lead to increased mortality. There are no vaccines currently known to combat necrotic enteritis.

“At the end of the day, if you’re not able to make a probiotic formulation that is safe, that is efficacious and also able to provide equal production parameters, it is not going to be an economically sound investment for producers,” said Dr Sharif.