Field Interventions Against Colonization of Broilers by Campylobacter

Campylobacteriosis and Control Strategies against Campylobacters in Poultry Farms

Campylobacteriosis is a significant foodborne illness caused by Campylobacter bacteria. It is one of the most common bacterial causes of gastroenteritis worldwide, with poultry being a major reservoir and source of infection in humans. In poultry farms, Campylobacters colonize the intestinal tract of chickens and contaminate meat during processing. Vaccines under development against Campylobacters in poultry showed partial or no protection against their cecal colonization. Therefore, this review will elaborate on campylobacteriosis and emphasize the control strategies and recent vaccine trials against Campylobacters in poultry farms. The epidemiology, diagnosis, and treatment of Campylobacter infection, along with specific mention of poultry Campylobacter contamination events in Malaysia, will also be discussed.

Combined application of bacteriophages with a competitive exclusion culture and carvacrol with organic acids can reduce Campylobacter in primary broiler production

For reducing Campylobacter (C.) in the food production chain and thus the risk to the consumer, the combined application of different measures as a multiple-hurdle approach is currently under discussion. This is the first study to investigate possible synergistic activities in vivo, aiming at reducing intestinal C. jejuni counts by administering (i) bacteriophages (phages) in combination with a competitive exclusion (CE) product and (ii) carvacrol combined with organic acids. The combined application of the two selected phages (Fletchervirus phage NCTC 12673 and Firehammervirus phage vB_CcM-LmqsCPL1/1) and the CE product significantly reduced C. jejuni loads by 1.0 log10 in cecal and colonic contents as well as in cloacal swabs at the end of the trial (33 and 34 days post hatch). The proportion of bacterial isolates showing reduced phage susceptibility ranged from 10.9% (isolates from cecal content) to 47.8% (isolates from cloacal swabs 32 days post hatch) for the Fletchervirus phage, while all tested isolates remained susceptible to the Firehammervirus phage. The use of carvacrol combined with an organic acid blend (sorbic acid, benzoic acid, propionic acid, and acetic acid) significantly reduced Campylobacter counts by 1.0 log10 in cloacal swabs on day 30 only.

Avian campylobacteriosis, prevalence, sources, hazards, antibiotic resistance, poultry meat contamination, and control measures: a comprehensive review

Avian campylobacteriosis is a vandal infection that poses human health hazards. Campylobacter is usually colonized in the avian gut revealing mild signs in the infected birds, but retail chicken carcasses have high contamination levels of Campylobacter spp. Consequently, the contaminated avian products constitute the main source of human infection with campylobacteriosis and result in severe clinical symptoms such as diarrhea, abdominal pain, spasm, and deaths in sensitive cases. Thus, the current review aims to shed light on the prevalence of Campylobacter in broiler chickens, Campylobacter colonization, bird immunity against Campylobacter, sources of poultry infection, antibiotic resistance, poultry meat contamination, human health hazard, and the use of standard antimicrobial technology during the chicken processing of possible control strategies to overcome such problems.

Deciphering the Association between Campylobacter Colonization and Microbiota Composition in the Intestine of Commercial Broilers

Campylobacter is a major food safety concern and is transmitted mainly via poultry meat. We previously found that some commercial broiler farms consistently produced Campylobacter-negative flocks while others were consistently Campylobacter-positive for consecutive production cycles although the farms operated under similar management practices. We hypothesized that this difference in Campylobacter colonization might be associated with the gut microbiota composition. To address this, six commercial broiler farms were selected based on their Campylobacter status (three negative and three positive) to evaluate the microbiota differences between each farm category. For each farm on each production cycle (2-3 cycles), 40 ceca collected from five-week-old broilers were processed for microbiota analysis via 16S rRNA gene sequencing. Cecal microbiota species richness, phylogenetic diversity, community structure, and composition of Campylobacter-positive farms were noticeably different from those of Campylobacter-negative farms. Rikenella, Methanocorpusculum, Barnesiella, Parasutterella, and Helicobacter were significantly more abundant among Campylobacter-positive farms. In contrast, Ruminococcaceae, Streptococcus, Escherichia, Eggerthellaceae, Lactobacillus, Monoglobus, and Blausia were more abundant in Campylobacter-negative farms. Eggerthellaceae, Clostridia, Lachnospiraceae, Lactobacillus, Monoglobus, and Parabacteroides were significantly negatively correlated with Campylobacter abundance. These findings suggest that specific members of cecal microbiota may influence Campylobacter colonization in commercial broilers and may be further explored to control Campylobacter in poultry.

Systematic review of products with potential application for use in the control of Campylobacter spp. in organic and free-range broilers

Campylobacter spp. are some of the most important food-borne zoonoses in Europe and broiler meat is considered the main source of Campylobacter infections. Organic and free-range broilers have access to outdoor reservoirs of Campylobacter and are more frequently infected at slaughter than the conventional broiler flocks. Limitations to biosecurity and treatment options in these production types calls for additional solutions. This review examines intervention methods with sufficient strength and quality, which are able to reduce the load of Campylobacter safely and efficiently and discuss their applicability in organic and free-range broiler production. Four different products passed the inclusion criteria and their quality examined: ferric tyrosine chelate, a prebiotic fermentation product of Saccharomyces cerevisiae, short-chain fatty acid butyrate coated on microbeads added to feed, and a mix of organic acids added to the drinking water. Though potential candidates for reducing Campylobacter in broilers were identified, there is a lack of large scale intervention studies that demonstrate an effect under field conditions of a free-range broiler production.

Management Strategies for Prevention of Campylobacter Infections Through the Poultry Food Chain: A European Perspective

Numerous studies point out that at present, a complete elimination of Campylobacter species in the poultry food chain is not feasible. Thus, the current aim should be to establish control measures and intervention strategies to minimize the occurrence of Campylobacter spp. in livestock (esp. poultry flocks) and to reduce the quantitative Campylobacter burden along the food chain in animals and subsequently in foods. The most effective measures to mitigate Campylobacter focus on the primary production stage. Nevertheless, measures applied during slaughter and processing complement the general meat hygiene approaches by reducing fecal contamination during slaughtering and processing and as a consequence help to reduce Campylobacter in poultry meat. Such intervention measures at slaughter and processing level would include general hygienic improvements, technological innovations and/or decontamination measures that are applied at single slaughter or processing steps. In particular, approaches that do not focus on a single intervention measure would need to be based on a thorough process of evaluation, and potential combinatory effects have to be modeled and tested. Finally, the education of all stakeholders (including retailers, food handlers and consumers) is required and will help to increase awareness for the presence of foodborne pathogens in raw meat and meat products and can thus aid in the development of the required good kitchen hygiene.

Cost-effectiveness analysis of using probiotics, prebiotics, or synbiotics to control Campylobacter in broilers

Campylobacter is a food safety hazard, which causes a substantial human disease burden. Infected broiler meat is a common source of campylobacteriosis. The use of probiotics, prebiotics, or synbiotics has been associated with controlling Campylobacter infections in broilers, although efficacy remains a contentiously debated issue. On-farm use of probiotics, prebiotics, or synbiotics is gaining momentum. Therefore, it is interesting to analyze the economic viability of this potential intervention to reduce Campylobacter prevalence in broilers. A normative cost-effectiveness analysis was conducted to estimate the cost-effectiveness ratio of using probiotics, prebiotics, or synbiotics in broiler production in Denmark, the Netherlands, Poland, and Spain. The cost-effectiveness ratio was defined as the estimated costs of probiotics, prebiotics, or synbiotics use divided by the estimated public health benefits expressed in euro (€) per avoided disability-adjusted life year (DALY). The model considered differences between the countries in zootechnical and economic farm performance, in import, export, and transit of live broilers, broiler meat and meat products, and in disease burden of Campylobacter-related human illness. Simulation results revealed that the costs per avoided DALY were lowest in Poland and Spain (€4,000-€30,000 per avoided DALY) and highest in the Netherlands and Denmark (€70,000-€340,000 per avoided DALY) at an efficacy ranging from 10 to 20%. In Poland and Spain, using probiotics can be classified as a moderately expensive intervention if efficacy is more than 10%, otherwise it is relatively expensive. In the Netherlands and Denmark, using probiotics is a relatively expensive intervention irrespective of efficacy. However, if probiotics, prebiotics, or synbiotics were assumed to enhance broiler performance, it would become a relatively cost-effective intervention for Campylobacter even at low efficacy levels of 1 to 10%.

Modulation of the Immune Response to Improve Health and Reduce Foodborne Pathogens in Poultry

Salmonella and Campylobacter are the two leading causes of bacterial-induced foodborne illness in the US. Food production animals including cattle, swine, and chickens are transmission sources for both pathogens. The number of Salmonella outbreaks attributed to poultry has decreased. However, the same cannot be said for Campylobacter where 50⁻70% of human cases result from poultry products. The poultry industry selects heavily on performance traits which adversely affects immune competence. Despite increasing demand for poultry, regulations and public outcry resulted in the ban of antibiotic growth promoters, pressuring the industry to find alternatives to manage flock health. One approach is to incorporate a program that naturally enhances/modulates the bird's immune response. Immunomodulation of the immune system can be achieved using a targeted dietary supplementation and/or feed additive to alter immune function. Science-based modulation of the immune system targets ways to reduce inflammation, boost a weakened response, manage gut health, and provide an alternative approach to prevent disease and control foodborne pathogens when conventional methods are not efficacious or not available. The role of immunomodulation is just one aspect of an integrated, coordinated approach to produce healthy birds that are also safe and wholesome products for consumers.

Salmonella control in poultry flocks and its public health impact

An increase in confirmed human salmonellosis cases in the EU after 2014 triggered investigation of contributory factors and control options in poultry production. Reconsideration of the five current target serovars for breeding hens showed that there is justification for retaining Salmonella Enteritidis, Salmonella Typhimurium (including monophasic variants) and Salmonella Infantis, while Salmonella Virchow and Salmonella Hadar could be replaced by Salmonella Kentucky and either Salmonella Heidelberg, Salmonella Thompson or a variable serovar in national prevalence targets. However, a target that incorporates all serovars is expected to be more effective as the most relevant serovars in breeding flocks vary between Member State (MS) and over time. Achievement of a 1% target for the current target serovars in laying hen flocks is estimated to be reduced by 254,400 CrI95[98,540; 602,700] compared to the situation in 2016. This translates to a reduction of 53.4% CrI95[39.1; 65.7] considering the layer-associated human salmonellosis true cases and 6.2% considering the overall human salmonellosis true cases in the 23 MSs included in attribution modelling. A review of risk factors for Salmonella in laying hens revealed that overall evidence points to a lower occurrence in non-cage compared to cage systems. A conclusion on the effect of outdoor access or impact of the shift from conventional to enriched cages could not be reached. A similar review for broiler chickens concluded that the evidence that outdoor access affects the occurrence of Salmonella is inconclusive. There is conclusive evidence that an increased stocking density, larger farms and stress result in increased occurrence, persistence and spread of Salmonella in laying hen flocks. Based on scientific evidence, an impact of Salmonella control programmes, apart from general hygiene procedures, on the prevalence of Campylobacter in broiler flocks at the holding and on broiler meat at the end of the slaughter process is not expected.