Prevalence and risk factors for Salmonella enterica subsp. enterica contamination in French breeding and fattening turkey flocks at the end of the rearing period

Prevalence and Association of Campylobacter spp., Salmonella spp., and Blastocystis sp. in Poultry

Poultry and poultry meat are considered the most important sources of human campylobacteriosis and salmonellosis. However, data about the occurrence of Campylobacter and Salmonella concomitantly with intestinal protozoa such as Blastocystis sp. in poultry remain very scarce. Therefore, this study aimed to investigate the presence and possible interactions between these three microorganisms in fecal samples from 214 chickens collected either on farms or from live bird markets in Egypt. The results obtained showed that Campylobacter spp., Salmonella spp., and Blastocystis sp. were present in 91.6% (196/214), 44.4% (95/214), and 18.2% (39/214) of tested samples, respectively, highlighting an active circulation of these microorganisms. Moreover, a significant positive correlation was reported between the occurrence of Campylobacter spp. and Blastocystis sp. together with a significant negative correlation between Blastocystis sp. and Salmonella spp. This study confirms the association reported previously between Blastocystis sp. and Campylobacter spp. while disclosing an association between Blastocystis sp. and Salmonella spp.; it also highlights the need to improve studies on the interactions between bacteria and eukaryotes in the gut microbiota of poultry.

Survey of Salmonellae occurrence in meat-producing rabbitries in Switzerland

BACKGROUND

An outbreak of salmonellosis due to Salmonella Typhimurium was detected coincidentally in a Swiss meat rabbitry, given that surveillance of Salmonella in rabbits is not mandatory in Switzerland.

METHODS

To assess the extent of potentially subclinical Salmonella carriage in meat rabbits, faecal pool samples of 50 farms (90% of Swiss commercial rabbitries) with ground covering litter and group housing were bacteriologically tested. Additionally, 236 rabbits showing clinical signs compatible with intestinal diseases, such as salmonellosis, were examined postmortem and analysed bacteriologically. Salmonella isolates were serotyped and analysed by whole genome sequencing (WGS).

RESULTS

Salmonella Typhimurium was detected in three commercial farms (6.0% of all tested farms). The affected farms were directly linked to the animal trade and Salmonella isolates were shown to be identical by WGS.

CONCLUSION

There is no increased hazard for Salmonella carriage in the animal welfare-friendly Swiss husbandry systems in general, despite risk factors such as ground covering litter.

Review of Quantitative Microbial Risk Assessment in Poultry Meat: The Central Position of Consumer Behavior

Food of animal origin, especially meat products, represent the main vehicle of foodborne pathogens and so are implicated in foodborne outbreaks. Poultry meat is a widely consumed food in various forms, but it is also a reservoir of thermotolerant Campylobacter and Salmonella bacterial species. To assess human health risks associated with pathogenic bacteria in poultry meat, the use of quantitative microbial risk assessment (QMRA) has increased over the years as it is recognized to address complex food safety issues and is recommended by health authorities. The present project reviewed poultry meat QMRA, identified key steps of the farm-to-fork chain with significant impacts on food safety, highlighted current knowledge gaps, and provided risk mitigation advices. A PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)-based systematic analysis was carried out and enabled the collection of 4056 studies including 42 QMRA kept for analysis after screening. The latter emphasized Campylobacter spp. and Salmonella spp. contaminations during the consumer stage as the main concern. The role of consumer handling on cross-contamination and undercooking events were of major concern. Thus, proper hygiene and safety practices by consumers have been suggested as the main intervention and would need to be followed with regular surveys to assess behavior changes and reduce knowledge gaps.

Isolation and Characterization of Multidrug-Resistant Escherichia coli and Salmonella spp. from Healthy and Diseased Turkeys

Diseases caused by Escherichia coli (E. coli) and Salmonella spp. can negatively impact turkey farming. The aim of this study was to isolate and characterize multidrug-resistant (MDR) E. coli and Salmonella spp. in healthy and diseased turkeys. A total of 30 fecal samples from healthy turkeys and 25 intestinal samples from diseased turkeys that died of enteritis were collected. Bacterial isolation and identification were based on biochemical properties and polymerase chain reaction (PCR). Antibiogram profiles were determined by disk diffusion. The tetracycline-resistance gene tetA was detected by PCR. All samples were positive for E. coli. Only 11 samples (11/30; 36.67%) were positive for Salmonella spp. from healthy turkeys, whereas 16 (16/25; 64%) samples were positive for Salmonella spp. from diseased turkeys. E. coli isolated from diseased turkeys showed higher resistance to levofloxacin, gentamicin, chloramphenicol, ciprofloxacin, streptomycin, and tetracycline. Salmonella spp. isolated from healthy turkeys exhibited higher resistance to gentamicin, chloramphenicol, ciprofloxacin, streptomycin, imipenem, and meropenem. All E. coli and Salmonella spp. from both healthy and diseased turkeys were resistant to erythromycin. Salmonella spp. from both healthy and diseased turkeys were resistant to tetracycline. Multidrug resistance was observed in both E. coli and Salmonella spp. from diseased turkeys. Finally, the tetA gene was detected in 93.1% of the E. coli isolates and in 92.59% of the Salmonella spp. isolates. To the best of our knowledge, this is the first study to isolate and characterize tetA-gene-containing MDR E. coli and Salmonella spp. from healthy and diseased turkeys in Bangladesh. Both microorganisms are of zoonotic significance and represent a significant public health challenge.

Isolation and identification of Salmonella pullorum bacteriophage YSP2 and its use as a therapy for chicken diarrhea

Salmonella pullorum is the major pathogen that is harmful to the poultry industry in developing countries, and the treatment of chicken diarrhea caused by S. pullorum has become increasingly difficult. In this study, a virulent bacteriophage YSP2, which was able to specifically infect Salmonella, was isolated and characterized. Phage YSP2 was classified in the Siphoviridae family and had a short latent period of 10 min. No bacterial virulence- or lysogenesis-related ORF is present in the YSP2 genome, making it eligible for use in phage therapy. Experiments in vivo investigated the potential use of phages as a therapy against diarrhea in chickens caused by S. pullorum in a chicken diarrhea model, demonstrating that a single oral administration of YSP2 (1 × 10¹⁰ PFU/mL, 80 μL/chicken) 2 h after S. pullorum oral administration at a double median lethal dose was sufficient to protect chickens against diarrhea. Gross inspection showed that YSP2 can effectively reduce organ damage and significantly relieve hemorrhage in the intestine and liver tissue. Moreover, YSP2 can maintain a high curative effect when diluted to 10⁸ PFU/mL. In light of its therapeutic effect on chicken diarrhea, YSP2 may serve as an alternative treatment strategy for infections caused by S. pullorum.

A longitudinal observational study of Salmonella shedding patterns by commercial turkeys during rearing and fattening, showing limitations of some control measures

1. The onset and progression of Salmonella infections was investigated in commercial turkey flocks from placement at 1 d old until slaughter in "brood and move" systems using a longitudinal observational approach based on faeces and environmental sampling with subsequent culture of Salmonella. 2. Persistent Salmonella Newport contamination was found within rearing houses and on their external concrete aprons after cleaning and disinfection between crops of heavily shedding young birds. 3. Salmonella shedding was often detected by 5 d of age and the frequency of positive samples peaked at 14-35 d. Thereafter Salmonella isolations declined, especially in the later (fattening) stages. Samples were still Salmonella-positive at low prevalence in half of the intensively sampled houses at slaughter age. 4. A number of management interventions to combat Salmonella infection of flocks, including sourcing policy, competitive exclusion cultures and cleaning and disinfection, were inadequate to prevent flock infection, although improved disinfection on one unit was associated with a delay in the onset of flock infection.

Listeria monocytogenes contamination in French breeding and fattening turkey flocks

This study aimed to collect data and create a database related to Listeria monocytogenes contamination in breeding and fattening turkey flocks. Seventy-five breeding turkey flocks and 86 fattening turkey flocks were sampled. Three hundred seventy-five and 428 samples were analyzed in breeding and fattening turkey flocks, respectively. L. monocytogenes was detected in 9 of 75 breeding flocks, leading to an estimated prevalence of 12% (95% confidence interval, 4.6-19.4). In fattening turkeys, the prevalence of L. monocytogenes-positive flocks was 9.3% (95% confidence interval, 3.1-15.5). The serotyping of L. monocytogenes strains highlighted the dominance of serovar 1/2a in breeding as well as in fattening turkeys. The relationship between rearing practices and L. monocytogenes status in turkey flocks was studied by using multiple correspondence analyses and then a hierarchical classification. Results were separated into two classes and revealed profiles that were associated with the presence or the absence of L. monocytogenes. This study highlighted the need to implement strict sanitary measures to reduce the risk of L. monocytogenes contamination in turkey production.