Recent Advances in Screening of Anti-Campylobacter Activity in Probiotics for Use in Poultry

Abstract

Campylobacteriosis is the most common cause of bacterial gastroenteritis worldwide. Campylobacter species involved in this infection usually include the thermotolerant species Campylobacter jejuni. The major reservoir for C. jejuni leading to human infections is commercial broiler chickens. Poultry flocks are frequently colonized by C. jejuni without any apparent symptoms. Risk assessment analyses have identified the handling and consumption of poultry meat as one of the most important sources of human campylobacteriosis, so elimination of Campylobacter in the poultry reservoir is a crucial step in the control of this foodborne infection. To date, the use of probiotics has demonstrated promising results to reduce Campylobacter colonization. This review provides recent insights into methods used for probiotic screening to reduce the prevalence and colonization of Campylobacter at the farm level. Different eukaryotic epithelial cell lines are employed to screen probiotics with an anti-Campylobacter activity and yield useful information about the inhibition mechanism involved. These in vitro virulence models involve only human intestinal or cervical cell lines whereas the use of avian cell lines could be a preliminary step to investigate mechanisms of C. jejuni colonization in poultry in the presence of probiotics. In addition, in vivo trials to evaluate the effect of probiotics on Campylobacter colonization are conducted, taking into account the complexity introduced by the host, the feed, and the microbiota. However, the heterogeneity of the protocols used and the short time duration of the experiments lead to results that are difficult to compare and draw conclusions at the slaughter-age of broilers. Nevertheless, the combined approach using complementary in vitro and in vivo tools (cell cultures and animal experiments) leads to a better characterization of probiotic strains and could be employed to assess reduced Campylobacter spp. colonization in chickens if some parameters are optimized.

Current and Potential Treatments for Reducing Campylobacter Colonization in Animal Hosts and Disease in Humans

“…Previous studies that investigated probiotics as anti- Campylobacter treatments have appeared promising (Saint-Cyr et al, 2016). Several of these studies have focused on preventing Campylobacter colonization in broiler chickens at the primary production stage, typically by competitive exclusion of the pathogen by the probiotics (Bratz et al, 2015; Ştef, 2016; Thomrongsuwannakij et al, 2016).…”

Coadministration of the Campylobacter jejuni N-Glycan-Based Vaccine with Probiotics Improves Vaccine Performance in Broiler Chickens

“…Calculations based on mathematical modeling indicate that decreasing the levels of C. jejuni colonization in chickens by 2 log 10 units would decrease the number of human campylobacteriosis cases 30-fold, and a reduction by 3 log 10 units would diminish the public health risk by at least 90% (6,7). Various control mechanisms to reduce C. jejuni colonization levels in poultry have been described, including hygiene and biosecurity practices, bacteriophage therapy, prebiotics, probiotics, bacteriocins, and vaccination (8)(9)(10). Although biosecurity measures have the potential to reduce the contamination of meat during slaughter, vaccination of poultry is considered the most promising solution to decrease C. jejuni levels at the source and to reduce the rate of human infections.…”

“…In order to prepare for the future ban on the use of antibiotics in North America, there is a growing need for new nonantibiotic alternatives to improve bird performance and simultaneously prevent the spread of zoonotic pathogens of human health importance, such as C. jejuni. Probiotics are already widely used as an alternative to antibiotics (9,29,30) in order to improve feed conversion. Several studies, with various results, also described the use of food additives, including oligofructose or organic acids (31,32), in addition to single or mixed cultures of bacteria such as Lactobacillus, Enterococcus, and Bifidobacterium species to reduce C. jejuni levels in chickens (9).…”

“…Probiotics are already widely used as an alternative to antibiotics (9,29,30) in order to improve feed conversion. Several studies, with various results, also described the use of food additives, including oligofructose or organic acids (31,32), in addition to single or mixed cultures of bacteria such as Lactobacillus, Enterococcus, and Bifidobacterium species to reduce C. jejuni levels in chickens (9). Probiotics were also shown to improve vaccine efficacy in chickens immunized against coccidiosis (33) or Newcastle and infectious bursal disease viruses (34) and during passive immunization against various Salmonella enterica serotypes (35).…”

The Periplasmic Chaperone Network of Campylobacter jejuni: Evidence that SalC (Cj1289) and PpiD (Cj0694) Are Involved in Maintaining Outer Membrane Integrity

“…As a strategically important food-borne pathogen, novel interventions are required to reduce the numbers of campylobacters in the human food-chain. As well as increased bio-security measures, targeted interventions such as poultry vaccines (recently reviewed by Riddle and Guerry, 2016) and the use of specific anti- Campylobacter agents or probiotics (Saint-Cyr et al, 2016) on farm have been proposed, but will require identification of appropriate targets and increased knowledge of C. jejuni physiology respectively.…”