Survival and Control of Campylobacter in Poultry Production Environment

Multidrug-resistant, hyperaerotolerant, and aerobic growth of Campylobacter jejuni and C. coli in retail broiler chicken meat in Selangor, Malaysia

Campylobacter spp. are one of the major zoonotic pathogens from chicken meat, causing world‑leading foodborne diseases. Thus, the aims of this study include monitoring the aerobic plate count (APC), the prevalence, and the characterisations (antimicrobial resistance, aerotolerance, aerobic growth, and plasmid profiling) of Campylobacter spp.. This study sampled 260 chicken thighs and drumsticks from retail supermarkets and wet markets in Selangor, Malaysia. Prevalence and microbial loads of Campylobacter spp. were assessed with the most probable number-polymerase chain reaction (MPN-PCR). Antibiotic resistance assay was conducted with disk diffusion assay with 12 types of antibiotics. Prevalence surveillance indicated that 68.9 % of Campylobacter spp., 47.7 % of C. jejuni, and 40.0 % of C. coli were detected. Co-contamination prevalence of C. jejuni and C. coli (28.46 %) occurred significantly higher than mono-contaminations, 19.62 % in C. jejuni and 11.54 % in C. coli, respectively. The microbial loads of Campylobacter spp., C. jejuni, and C. coli were 1.02 ± 0.83 log MPN/g, 0.60 ± 0.57 log MPN/g, and 0.53 ± 0.58 log MPN/g, respectively. C. jejuni and C. coli showed extremely high resistance against nalidixic acid, ciprofloxacin, cephalothin, and ampicillin. Campylobacter spp. isolated exhibited aberrance from their microaerophilic nature, with 87.5 % of C. jejuni being HAT (hyperaerotolerant) and 12.5 % of C. jejuni were AT (aerotolerant), while 100 % of C. coli were HAT. Alarmingly, the aerobic condition did not confine the growth, as 18.75 % of C. jejuni demonstrated aerobic growth. Hence, our study accentuates the current risk profile of C. jejuni and C. coli from retail broiler chicken meat.

A multi-antigen Campylobacter vaccine enhances antibody responses in layer breeders and sustains elevated maternal antibody levels in their offspring

Campylobacter jejuni is the leading cause of bacterial gastroenteritis worldwide, with an estimated 1.5 million human infections occurring annually in the United States alone. With chickens being considered the primary reservoir and source of infection in humans, developing effective vaccination strategies is crucial for preventing Campylobacter transmission to humans. This study aimed to examine the immunogenicity and protective efficacy of a multi-antigen subunit vaccine, consisting of C. jejuni outer membrane proteins (OMPs) and cytosine-phosphorothioate-guanine oligodeoxynucleotides (CpG ODN), in layer breeders and its potential to enhance the levels of C. jejuni-specific maternal antibodies in their offspring. Four groups of layer breeders were subcutaneously vaccinated with 200 μg C. jejuni OMPs and 50 μg CpG-ODN, individually or combined, or with PBS as a negative control. C. jejuni shedding and antibody levels were monitored in breeders for up to ten weeks post-vaccination. At the peak of antibody levels (the fourth week post-primary vaccination), fertilized eggs were collected and incubated in a sensitized egg incubator until hatching. Maternally derived antibodies (MDA) were measured in the serum of hatched chicks for five weeks post-hatch. The results revealed that breeders vaccinated with the combination of C. jejuni OMPs and CpG ODN exhibited a significant reduction in C. jejuni shedding by up to 1.37 log10. This group also showed significantly higher serum and egg yolk IgY and IgM levels compared to the non-vaccinated negative control group, and notably, their chicks maintained significantly higher serum IgY, IgM, and IgA levels for five weeks post-hatch compared to the negative control group. Overall, these outcomes suggest that a combination of C. jejuni OMPs and CpG ODN could offer a promising vaccine strategy to reduce Campylobacter colonization in breeders and to boost and sustain high levels of C. jejuni-specific MDA in hatched chicks. Further research is needed to evaluate the protective effects of vaccine-associated MDA against Campylobacter infection in a commercial broiler model.

Campylobacter jejuni ST353 and ST464 cause localized gut inflammation, crypt damage, and extraintestinal spread during large- and small-scale infection in broiler chickens

Campylobacter infections in humans and chickens are a significant burden to health services and the poultry industry. In the UK, over 75% of chicken products are Campylobacter-positive at retail, but the knowledge of the mechanisms responsible for extraintestinal spread into edible tissues remains incomplete. This work aimed to establish if two chicken-associated lineages of Campylobacter jejuni, ST353 and ST464, have the potential for extraintestinal spread. Large- and small-scale chicken colonization trials investigated the infection biology of C. jejuni ST353 (three strains) and ST464 (four strains). Both lineages strongly colonized the ileum and ceca and were detected in liver and spleen. C. jejuni ST353 and ST464 spleen load were significantly increased compared to C. jejuni M1 controls. Immune responses in cecal tonsils exhibited early induction of IFN-γ and suppressed TGFβ at 7 days post-infection with C. jejuni ST464. Histochemistry of gut tissue demonstrated significant decreases in intestinal crypt depth in ileal tissue with increasing severity relative to Campylobacter lineage, M1 Collapse

Key Words

• Campylobacter jejuni
• biomarkers
• broiler chicken
• cecal tonsil-derived cytokine production
• crypt depth
• gut damage
• gut health
• in vivo chicken infection

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MESH Headings

• Campylobacter jejuni/physiology
• Chickens/microbiology
• Animals
• Campylobacter Infections/microbiology
• Campylobacter Infections/veterinary
• Poultry Diseases/microbiology
• Inflammation/microbiology
• Spleen/microbiology
• Spleen/pathology
• Cecum/microbiology
• Cecum/pathology

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Grants

• BB019142/1 UKRI | Biotechnology and Biological Sciences Research Council (BBSRC)

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Affiliation(s)

Heather M Chick Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
Lisa K Williams Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom Department of Animal and Agriculture, Hartpury University, Gloucester, United Kingdom
Nick Sparks Scotland's Rural College (SRUC) Barony Campus, Dumfries, United Kingdom
Farina Khattak Monogastric Science Research Center, Scotland's Rural College (SRUC), Edinburgh, United Kingdom
Paul Vermeij MSD Animal Health, Boxmeer, the Netherlands
Inge Frantzen MSD Animal Health, Boxmeer, the Netherlands
Mandy Peeters MSD Animal Health, Boxmeer, the Netherlands
Jetta J E Bijlsma MSD Animal Health, Boxmeer, the Netherlands
Daniel John Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
Timothy Ogunrin Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
Keioni Essex Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
Caroline Cayrou Genetics, Genomics, and Cancer Sciences, University of Leicester, Leicester, United Kingdom
Venkateswarlu Kanamarlapudi Cellular Biology, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
Christopher D Bayliss Genetics, Genomics, and Cancer Sciences, University of Leicester, Leicester, United Kingdom
Julian M Ketley Genetics, Genomics, and Cancer Sciences, University of Leicester, Leicester, United Kingdom
Thomas J Humphrey Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
Steven P Rushton School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
Thomas S Wilkinson Microbiology and Infectious Disease, Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom

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Deaminase inhibitor and casein hydrolysates drive microbial shifts favoring Campylobacter jejuni in an in vitro poultry cecal model

AIM

The dietary proteins in poultry feeds, including the polypeptide chain size, influence gut microbial composition and function. This study assessed the microbial preference for peptide size using the same protein source in three polypeptide forms.

METHODS AND RESULTS

We investigated the effects of diphenyliodonium chloride (DIC) on poultry cecal microbiota inoculated with Campylobacter jejuni and supplemented with various casein hydrolysates (intact casein, enzyme hydrolysate, acid hydrolysate, and a mix of all three) using an in vitro cecal model. The incubation occurred over 18 h at 42°C under microaerophilic conditions. We hypothesized a decrease in C. jejuni abundance by limiting nitrogenous metabolites while promoting the growth of protein fermentative bacteria. Additionally, we speculated that the response to DIC would vary with different polypeptides. Genomic DNA was extracted, amplified, and sequenced on an Illumina MiSeq platform. Analysis within QIIME2-2021.11 showed that DIC treatments did not significantly affect C. jejuni abundance but drastically decreased Enterobacteriaceae abundance (ANCOM, P < 0.05). DIC-treated groups exhibited a more stable community structure, especially in the peptide-amended group. Microbial interactions likely aided C. jejuni survival in DIC groups with casein hydrolysates. Methanocorpusculum, Phascolarctobacterium, and Campylobacter formed a core microbial community in both DIC-treated and non-treated groups. DIC altered co-occurrence patterns among core members and differentiated taxa in abundance in acid and peptide-DIC treated groups, changing negative relationships to positive ones (Spearman's Correlation, P < 0.05). Variations in polypeptide composition affected metabolite abundance, notably impacting the urea cycle in Campylobacter and Clostridiaceae. DIC shifted communal energy metabolism in microbiota on casein sources.

CONCLUSION

Campylobacter's adaptability to the deaminase inhibitor indicates reliance on the microbial community and their metabolic products, showcasing its metabolic versatility.

The Global Challenge of Campylobacter: Antimicrobial Resistance and Emerging Intervention Strategies

Antimicrobial resistance (AMR) in Campylobacter species, particularly C. jejuni and C. coli, poses a significant public health threat. These bacteria, which are commonly found in livestock, poultry, companion animals, and wildlife, are the leading causes of foodborne illnesses, often transmitted through contaminated poultry. Extensive exposure to antibiotics in human and veterinary medicine creates selection pressure, driving resistance through mechanisms such as point mutations, horizontal gene transfer, and efflux pumps. Resistance to fluoroquinolones, macrolides, and tetracyclines complicates treatment and increases the risk of severe infections. Drug-resistant Campylobacter is transmitted to humans via contaminated food, water, and direct contact with animals, highlighting its zoonotic potential. Addressing this challenge requires effective interventions. Pre-harvest strategies like biosecurity and immune-based methods reduce bacterial loads on farms, while post-harvest measures, including carcass decontamination and freezing, limit contamination. Emerging approaches, such as bacteriocins and natural antimicrobials, offer chemical-free alternatives. Integrated, multidisciplinary interventions across the food chain are essential to mitigate AMR transmission and enhance food safety. Sustainable agricultural practices, antimicrobial stewardship, and innovative solutions are critical to curbing Campylobacter resistance and protecting global public health. Our review examines the dynamics of antimicrobial resistance in Campylobacter and presents current strategies to mitigate Campylobacter-related AMR, offering valuable insights for antimicrobial control in the poultry industry.

Environmental Exposures Associated with Enteropathogen Infection in Six-Month-Old Children Enrolled in the ECoMiD Cohort along a Rural-Urban Gradient in Northern Ecuador†

Enteropathogens are major contributors to mortality and morbidity, particularly in settings with limited access to water, sanitation, and hygiene infrastructure. To assess transmission pathways associated with enteropathogen infection, we measured household environmental conditions and assayed 22 enteropathogens using TaqMan Array Cards in stool samples from 276 six-month-old children living in communities along a rural-urban gradient in Northern Ecuador. We utilized multivariable models, risk factor importance, and distance-based statistical methods to test factors associated with infection. Most children (89%) carried at least one pathogen, and 72% carried two or more. Bacterial infections (82% of participants) were more common than viruses (58%) or parasites (9.1%). Infants living in the urban site had decreased infection risks compared to those in rural locations. Improved water and sanitation were most predictive of reduced infection risk. Improved water was associated with decreased enterotoxigenic E. coli prevalence, and improved sanitation was associated with lower prevalence of any infection and specifically norovirus. Animal exposure was associated with increased Salmonella prevalence. Children measured during the rainy season had fewer viral and more bacterial infections. Identifying environmental exposures associated with specific pathogen outcomes provides insights into transmission pathways, which contribute critical information for developing effective strategies to improve child health.

A Longitudinal Study on Campylobacter spp. in an Integrated Broiler Complex in the Southeast Region of the United States: Prevalence and Phylogenetic Analysis

Poultry meat products are considered the major contributors to Campylobacteriosis in humans. The objective of this study was to determine the prevalence status, critical entry points, and movement patterns of Campylobacter spp. along different stages of an integrated broiler complex. To isolate bacteria and perform phylogenetic analysis, a total of 790 environmental samples were collected from 38 production houses, a hatchery, 6 transport trucks, and a processing plant of a commercial broiler complex. Odds ratio and 95% confidence intervals were compared among different stages and sample types (α = 0.05). Altogether 17% (137/790) of samples and 61% (23/38) of production houses were positive for Campylobacter spp. Similarly, 34% (46/135) of samples were identified as Campylobacter jejuni (C. jejuni), and 61% (83/135) were identified as Campylobacter coli (C. coli). The odds of Campylobacter spp. detection in broiler farms' surroundings were 4 times (1.88-8.26; 95% CLs) more likely as compared to parent pullets and breeder farms' surroundings (p = 0.0004). Similarly, among different sample types, the odds of Campylobacter spp. detection in boot swabs and sponge-stick swabs were more likely as compared to fly paper samples (p ≤ 0.0024). In addition, the odds of Campylobacter spp. detection in postpick whole carcass rinses were 4 times (1.99-7.59; 95% CLs) more likely as compared to postchill carcass rinses (p = 0.0004). The phylogeny results of both C. jejuni and C. coli indicate multiple critical entry points of bacterial strains along the chain and suggest the possibility of transmission of Campylobacter spp. from broiler grow-out flocks through transport and to final raw products (29%) in the processing plant. The results indicate potential risks of foodborne infections in consumers from ingestion of contaminated raw or undercooked poultry meat. Therefore, a comprehensive control strategy may be essential to reduce or eliminate Campylobacter spp. or other zoonotic pathogens from the poultry food chain.

Mechanistic concepts involved in biofilm associated processes of Campylobacter jejuni: persistence and inhibition in poultry environments

Campylobacter species, predominantly Campylobacter jejuni, remains a significant zoonotic pathogen worldwide, with the poultry sector being the primary vector for human transmission. In recent years. there has been a notable rise in the incidence of human campylobacteriosis, necessitating a deeper understanding of the pathogen's survival mechanisms and transmission dynamics. Biofilm presence significantly contributes to C. jejuni persistence in poultry and subsequent food product contamination, and this review describes the intricate processes involved in biofilm formation. The ability of Campylobacter to form biofilms on various surfaces, including stainless steel, plastic, and glass, is a critical survival strategy. Campylobacter biofilms, with their remarkable resilience, protect the pathogen from environmental stresses such as desiccation, pH extremes, biocides and sanitizing agents. This review explores the molecular and genetic mechanisms of C. jejuni biofilm formation, highlighting regulatory genes involved in motility, chemotaxis, and stress responses. Flagellar proteins, particularly flaA, flaB, flaG, and adhesins like cadF and flpA, are identified as the main molecular components in biofilm development. The role of mixed-species biofilms, where C. jejuni integrates into existing biofilms of other bacteria to enhance pathogen resilience, is also discussed. This review also considers alternative interventions to control C. jejuni in poultry production, in the context of increasing antibiotic resistance. It explores the effectiveness of prebiotics, probiotics, synbiotics, bacteriocins, bacteriophages, vaccines, and organic acids, with a focus on their mechanisms of action in reducing bacterial colonization and biofilm formation. Studies show that mixtures of organic acids and compounds like Carvacrol and Eugenol significantly downregulate genes linked with motility and adhesion, thereby disrupting biofilm integrity. It discusses the impact of environmental factors, such as temperature and oxygen levels on biofilm formation, providing insights into how industrial conditions can be manipulated to reduce contamination. This paper stresses the need for a multifaceted approach to control Campylobacter in poultry, integrating molecular and genetic insights with practical interventions. By advancing our understanding of biofilm dynamics and gene regulation, we aim to inform the development of more effective strategies to enhance food safety and protect public health.

Quantitative assessment and genomic profiling of Campylobacter dynamics in poultry processing: a case study in the United Arab Emirates integrated abattoir system

In the United Arab Emirates, no previous research has investigated the dynamics of the foodborne pathogen Campylobacter in broiler abattoir processing. This study conducted in one of the largest poultry producers in the UAE, following each key slaughter stage-defeathering, evisceration, and final chilling-five broiler carcasses were collected from 10 slaughter batches over a year. Additionally, one caecum was obtained from 15 chickens in each slaughter batch to evaluate the flock colonization. In total, 300 samples (150 carcasses and 150 caeca) were collected and enumerated for Campylobacter using standard methods. Campylobacter was pervasive in caecal samples from all slaughter batches, with 86% of carcasses post-defeathering and evisceration stages and 94% post-chilling tested positive for Campylobacter. Campylobacter coli predominates in 55.2% of positive samples, followed by Campylobacter jejuni in 21%, with both species co-existing in 23.8% of the samples. Campylobacter counts in caecal contents ranged from 6.7 to 8.5 log10 CFU/g, decreasing post-defeathering and evisceration to 3.5 log10 CFU/g of neck skin and further to 3.2 log10 CFU/g of neck skin post-evisceration. After chilling, 70% of carcasses exceeded 3 log10 CFU/g of neck skin. Whole-genome sequencing (WGS) of 48 isolates unveiled diverse sequence types and clusters, with isolates sharing the same clusters (less than 20 single nucleotide polymorphisms) between different farms, different flocks within the same farm, as well as in consecutive slaughter batches, indicating cross-contamination. Multiple antimicrobial resistance genes and mutations in gyrA T86I (conferring fluoroquinolone resistance) and an RNA mutation (23S r.2075; conferring macrolide resistance) were widespread, with variations between C. coli and C. jejuni. WGS results revealed that selected virulence genes (pglG, pseD, pseI, flaA, flaB, cdtA, and cdtC) were significantly present in C. jejuni compared to C. coli isolates. This study offers the first insights into Campylobacter dynamics in poultry processing in the UAE. This work provides a base for future research to explore additional contributors to Campylobacter contamination in primary production. In conclusion, effective Campylobacter management demands a comprehensive approach addressing potential contamination sources at every production and processing stage, guided by continued microbiological surveillance and genomic analysis to safeguard public health and food safety.

Campylobacteriosis: A rising threat in foodborne illnesses

Campylobacteriosis is a foodborne illness that is contracted by eating contaminated food, particularly animal products like meat from diseased animals or corpses tainted with harmful germs. The epidemiology of campylobacteriosis varies significantly between low-, middle-, and high-income countries. Campylobacter has a complicated and poorly known survival strategy for getting past host barriers and causing sickness in humans. The adaptability of Campylobacter to unfavorable environments and the host's immune system seems to be one of the most crucial elements of intestinal colonization. A Campylobacter infection may result in fever, nausea, vomiting, and mild to severe bloody diarrhea in humans. Effective and rapid diagnosis of Campylobacter species infections in animal hosts is essential for both individual treatment and disease management at the farm level. According to the most recent meta-analysis research, the main risk factor for campylobacteriosis is travel, which is followed by eating undercooked chicken, being exposed to the environment, and coming into close contact with livestock. Campylobacter jejuni, and occasionally Campylobacter coli, are the primary causes of Campylobacter gastroenteritis, the most significant Campylobacter infection in humans for public health. The best antibiotic medications for eradicating and decreasing Campylobacter in feces are erythromycin, clarithromycin, or azithromycin. The best strategy to reduce the number of human infections caused by Campylobacter is to restrict the amount of contamination of the poultry flock and its products, even if the majority of infections are contracted through handling or ingestion of chicken.

Assessment of probiotic Bacillus velezensis supplementation to reduce Campylobacter jejuni colonization in chickens

Campylobacter jejuni continues to be a major public health issue worldwide. Poultry are recognized as the main reservoir for this foodborne pathogen. Implementing measures to decrease C. jejuni colonization on farms has been regarded as the most effective strategy to control the incidence of campylobacteriosis. The probiotics supplementation has been regarded as an attractive approach against C. jejuni in chickens. Here the inhibitory effects of one probiotic B. velezensis isolate CAU277 against C. jejuni was evaluated in vitro and in vivo. The in vitro antimicrobial activity showed that the supernatant of B. velezensis exhibited the most pronounced inhibitory effects on Campylobacter strains compared to other bacterial species. When co-cultured with B. velezensis, the growth of C. jejuni reduced significantly from 7.46 log10 CFU/mL (24 h) to 1.02 log10 CFU/mL (48 h). Further, the antimicrobial activity of B. velezensis against C. jejuni remained stable under a broad range of temperature, pH, and protease treatments. The in vivo experiments demonstrated that oral administration of B. velezensis significantly reduced the colonization of C. jejuni by 2.0 log10 CFU/g of feces in chicken cecum at 15 d postinoculation. In addition, the supplementary of B. velezensis significantly increased microbial species richness and diversity in chicken ileum, especially enhanced the bacterial population of Alistipes and Christensenellaceae, and decreased the existence of Lachnoclostridium. Our study presents that B. velezensis possesses antimicrobial activities against C. jejuni and promotes microbiota diversity in chicken intestines. These findings indicate a potential to develop an effective probiotic additive to control C. jejuni infection in chicken.

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.

Microbial profile of broiler carcasses processed at a university scale mobile poultry processing unit

Chicken and chicken products have been associated with foodborne pathogens such as Salmonella, Campylobacter, and Escherichia coli (E. coli). Poultry comprises an important segment of the agricultural economy (75 million birds processed as of 2019) in West Virginia (WV). The risk of pathogens on processed chickens has risen with the increased popularity of mobile poultry processing units (MPPUs). This study evaluated the microbial safety of broilers processed in a MPPU in WV. This study assessed aerobic plate counts (APCs), E. coli counts and the presence/absence of Salmonella and Campylobacter on 96 broiler carcasses following each MPPU step of scalding, eviscerating, and chilling. Samples were either chilled in ice water only (W) or ice water with 5 ppm chlorine (CW). The highest number of bacteria recovered from carcasses were APCs (4.21 log10CFU/mL) and E. coli (3.77 log10CFU/mL; P = 0.02). A total reduction of 0.30 (P = 0.10) and 0.63 (P = 0.01) log10CFU/mL for APCs and E. coli, respectively, occurred from chilling carcasses in CW. Overall, results show that E. coli, Salmonella, and Campylobacter were significantly (P < 0.05) reduced from the initial scalding to the chilling step. However, Salmonella frequency doubled (15.63-34.38%) after the evisceration step, indicating that washing carcasses after evisceration may be a critical control point in preventing cross-contamination by Salmonella. Proper chilling is also an important microbial mitigation step in MPPU processing. Results indicate that Campylobacter was more resistant to chilling than Salmonella. Campylobacter was not completely inactivated until carcasses were chilled in CW, whereas W was sufficient to reduce Salmonella on carcasses. The results led to the conclusion that although 5 ppm chlorine (Cl2) achieved more bacterial reductions than water alone, the reductions were not always significant (P > 0.05). Further MPPU studies are needed to verify more effective chilling and processing strategies.

Prevalence of multidrug-resistant Campylobacter species in wastewater effluents: A menace of environmental and public health concern

The prevalence of multidrug-resistant Campylobacter species in wastewater effluents presents a formidable challenge at the intersection of environmental sustainability and public health. This study examined the presence of multidrug-resistant Campylobacter in wastewater effluents in the Eastern Cape Province, South Africa, and its implications for environmental ecosystems and public health. Forty-five samples from household effluent (HHE) and wastewater treatment plant effluent (WWTPE) were collected at different geographical locations within the province between April and September 2022. The counts of the presumptive Campylobacter genus ranged from 5.2 × 103 to 6.03 × 104 CFU/mL for HHE and 4.93 × 103 to 1.04 × 104 CFU/mL for WWTPE. About 42.55% of the samples were positive for Campylobacter species. Five virulence determinants including the cadF and wlaN were detected in all the isolates; however, flgR (19.23%), ciaB, and ceuE (15.38%) were less prevalent. The antibiogram profiles of confirmed Campylobacter isolates revealed high resistance (>55%) against all tested antibiotics ranging from 55.77% (nalidixic acid) to 92.30% (erythromycin), and resistance against the other antibiotics followed the order ciprofloxacin (51.92%), azithromycin (50%), and levofloxacin (48.08%). On the contrary, gentamicin was sensitive against 61.54% of the isolates, followed by imipenem (57.69%) and streptomycin (51.92%). The WWTPE's antibiotic resistance index (ARI) was 0.19, lower than the permitted Krumperman threshold of 0.2; and HHE's ARIs were higher. The isolates' respective multiple antibiotic resistance indexes (MARI) varied between 0.08 and 1.00. Among the phenotypically resistant Campylobacter isolates examined, 21 resistance determinants encoding resistance against β-lactam, carbapenems, aminoglycosides, phenicol, quinolones, tetracyclines, and macrolides were detected, which explains the phenotypic resistance observed in the study. This study concludes that the wastewaters in the study areas are important reservoirs of multidrug-resistant and potentially pathogenic Campylobacter species, suggesting the need for proper treatment of the wastewaters to eliminate the organisms in the effluents before discharge the final effluent to the receiving watershed.

Investigation of Potential Gut Health Biomarkers in Broiler Chicks Challenged by Campylobacter jejuni and Submitted to a Continuous Water Disinfection Program

The exploration of novel biomarkers to assess poultry health is of paramount importance, not only to enhance our understanding of the pathogenicity of zoonotic agents but also to evaluate the efficacy of novel treatments as alternatives to antibiotics. The present study aimed to investigate potential gut health biomarkers in broiler chicks challenged by Campylobacter jejuni and subjected to a continuous water disinfection program. A total of 144 one-day-old hatched broiler chicks were randomly allocated to four treatment groups with four replicates each, according to the following experimental design: Group A received untreated drinking water; Group B received drinking water treated with 0.01-0.05% v/v Cid 2000™ (hydrogen peroxide, acetic acid and paracetic acid); Group C was challenged by C. jejuni and received untreated drinking water; and Group D was challenged by C. jejuni and received drinking water treated with 0.01-0.05% v/v Cid 2000™. The use of Cid 2000™ started on day 1 and was applied in intervals until the end of the experiment at 36 days, while the C. jejuni challenge was applied on day 18. Potential biomarkers were investigated in serum, feces, intestinal tissue, intestinal content, and liver samples of broilers. Statistical analysis revealed significant increases (p < 0.001) in serum cortisol levels in C. jejuni-challenged broilers. Serum fluorescein isothiocyanate dextran (FITC-d) increased significantly (p = 0.004) in broilers challenged by C. jejuni and treated with drinking water disinfectant, while fecal ovotransferrin concentration also increased significantly (p < 0.001) in broilers that received the drinking water disinfectant alone. The gene expression levels of occludin (p = 0.003) and mucin-2 (p < 0.001) were significantly upregulated in broilers challenged by C. jejuni, while mucin-2 significantly increased in birds that were challenged and received the drinking water disinfectant (p < 0.001). TLR-4 expression levels were significantly (p = 0.013) decreased in both groups that received the drinking water disinfectant, compared to the negative control group. Finally, the C. jejuni challenge significantly increased (p = 0.032) the crypt depth and decreased (p = 0.021) the villus height-to-crypt-depth ratio in the ileum of birds, while the tested disinfectant product increased (p = 0.033) the villus height in the jejunum of birds. Furthermore, the counts of C. jejuni in the ceca of birds (p = 0.01), as well as its translocation rate to the liver of broilers (p = 0.001), were significantly reduced by the addition of the water disinfectant. This research contributes to novel insights into the intricate interplay of water disinfection and/or C. jejuni challenge with potential intestinal biomarkers. In addition, it emphasizes the need for continued research to unveil the underlying mechanisms, expands our understanding of broiler responses to these challenges and identifies breakpoints for further investigations.

Multi-Omics of Campylobacter jejuni Growth in Chicken Exudate Reveals Molecular Remodelling Associated with Altered Virulence and Survival Phenotypes

Campylobacter jejuni is the leading cause of foodborne human gastroenteritis in the developed world. Infections are largely acquired from poultry produced for human consumption and poor food handling is thus a major risk factor. Chicken exudate (CE) is a liquid produced from defrosted commercial chicken products that facilitates C. jejuni growth. We examined the response of C. jejuni to growth in CE using a multi-omics approach. Changes in the C. jejuni proteome were assessed by label-based liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). We quantified 1328 and 1304 proteins, respectively, in experiments comparing 5% CE in Mueller-Hinton (MH) medium and 100% CE with MH-only controls. These proteins represent 81.8% and 80.3% of the predicted C. jejuni NCTC11168 proteome. Growth in CE induced profound remodelling of the proteome. These changes were typically conserved between 5% and 100% CE, with a greater magnitude of change observed in 100% CE. We confirmed that CE induced C. jejuni biofilm formation, as well as increasing motility and resistance against oxidative stress, consistent with changes to proteins representing those functions. Assessment of the C. jejuni metabolome showed CE also led to increased intracellular abundances of serine, proline, and lactate that were correlated with the elevated abundances of their respective transporters. Analysis of carbon source uptake showed prolonged culture supernatant retention of proline and succinate in CE-supplemented medium. Metabolomics data provided preliminary evidence for the uptake of chicken-meat-associated dipeptides. C. jejuni exposed to CE showed increased resistance to several antibiotics, including polymyxin B, consistent with changes to tripartite efflux system proteins and those involved in the synthesis of lipid A. The C. jejuni CE proteome was also characterised by very large increases in proteins associated with iron acquisition, while a decrease in proteins containing iron-sulphur clusters was also observed. Our data suggest CE is both oxygen- and iron-limiting and provide evidence of factors required for phenotypic remodelling to enable C. jejuni survival on poultry products.

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.

Identification of novel small molecule inhibitors of twin arginine translocation (Tat) pathway and their effect on the control of Campylobacter jejuni in chickens

Introduction

Control of Campylobacter from farm to fork is challenging due to the frequent emergence of antimicrobial-resistant isolates. Furthermore, poultry production systems are known reservoirs of Campylobacter. The twin-arginine translocation (Tat) pathway is a crucial bacterial secretion system that allows Campylobacter to colonize the host intestinal tract by using formate as the main source of energy. However, Tat pathway is also a major contributing factor for resistance to copper sulfate (CuSO4).

Methods

Since mammals and chickens do not have proteins or receptors that are homologous to bacterial Tat proteins, identification of small molecule (SM) inhibitors targeting the Tat system would allow the development of safe and effective control methods to mitigate Campylobacter in infected or colonized hosts in both pre-harvest and post-harvest. In this study, we screened 11 commercial libraries (n = 50,917 SM) for increased susceptibility to CuSO4 (1 mM) in C. jejuni 81-176, a human isolate which is widely studied.

Results

Furthermore, we evaluated 177 SM hits (2.5 μg/mL and above) that increased the susceptibility to CuSO4 for the inhibition of formate dehydrogenase (Fdh) activity, a Tat-dependent substrate. Eight Tat-dependent inhibitors (T1-T8) were selected for further studies. These selected eight Tat inhibitors cleared all tested Campylobacter strains (n = 12) at >10 ng/mL in the presence of 0.5 mM CuSO4in vitro. These selected SMs were non-toxic to colon epithelial (Caco-2) cells when treated with 50 μg/mL for 24 h and completely cleared intracellular C. jejuni cells when treated with 0.63 μg/mL of SM for 24 h in the presence of 0.5 mM of CuSO4. Furthermore, 3 and 5-week-old chicks treated with SM candidates for 5 days had significantly decreased cecal colonization (up to 1.2 log; p < 0.01) with minimal disruption of microbiota. In silico analyses predicted that T7 has better drug-like properties than T2 inhibitor and might target a key amino acid residue (glutamine 165), which is located in the hydrophobic core of TatC protein.

Discussion

Thus, we have identified novel SM inhibitors of the Tat pathway, which represent a potential strategy to control C. jejuni spread on farms.

Overview of Ecology and Aspects of Antibiotic Resistance in Campylobacter spp. Isolated from Free-Grazing Chicken Tissues in Rural Households

Rural households all over the world rear backyard chicken mainly for their own consumption and, to a lesser extent, for barter trade. These chickens represent a staple dish with numerous culinary variations and a cheap source of protein. Although some Campylobacter species, and particularly Campylobacter jejuni and Campylobacter coli, have been associated with industrial poultry carcasses, studies concerning the ecology of this genus in rural households do not exist. To assess the prevalence of Campylobacter species in the tissues of backyard chickens, samples were collected from birds Gallus domesticus bred in households in the rural area of Epirus (Greece), and Campylobacter strains were isolated by quantitative methods at 37 °C and 42 °C. In total, 256 strains were identified, belonging to 17 Campylobacter species, with C. jejuni and C. coli being the most prevalent. From the four ecological parameters studied (size of the flock, presence of small ruminants in the same household, presence of other poultry species in the same household, and feeding leftovers of the household), the size of the flock and the presence of small ruminants and/or pigs in the same household mostly affected the distribution of these strains. To study the phenotypical resistance against 14 antibiotics, 215 strains were selected. The results showed a high prevalence of multidrug-resistance (MDR) strains extending to all classes of antibiotics. Further genome analysis revealed the presence of genes coding resistance (blaOxA-61, tet(O), tet(A) cmeA, cmeB, cmeC, and gyrA (Thr-86-Ile mutation)), with the efflux pump CmeABC being the most prevalent. All antimicrobial resistance-encoded genes co-circulated, except for blaOXA-61, which moved independently. The minimum inhibitory concentration (MIC) values of two out of three antibiotics (representing different classes) were reduced when the strains tested were exposed to carbonyl cyanide 3-chlorophenylhydrazone (CCCP), a known efflux pump inhibitor. The same result was obtained with the addition of CCCP to the MIC values of bile salts. These results lead to the conclusion that Campylobacter species are present in an impressive diversity in backyard chicken tissues and that they exert a significant resistance to antibiotics, raising a potential danger for public health.

Broiler farming practices using new or re-used bedding, inclusive of free-range, have no impact on Campylobacter levels, species diversity, Campylobacter community profiles and Campylobacter bacteriophages

A multi-stage option to address food-safety can be produced by a clearer understanding of Campylobacter's persistence through the broiler production chain, its environmental niche and its interaction with bacteriophages. This study addressed Campylobacter levels, species, genotype, bacteriophage composition/ levels in caeca, litter, soil and carcasses across commercial broiler farming practices to inform on-farm management, including interventions. Broilers were sequentially collected as per company slaughter schedules over two-years from 17 farms, which represented four commercially adopted farming practices, prior to the final bird removal (days 39-53). The practices were conventional full clean-out, conventional litter re-use, free-range-full cleanout and free-range-litter re-use. Caeca, litter and soil collected on-farm, and representative carcases collected at the processing plant, were tested for Campylobacter levels, species dominance and Campylobacter bacteriophages. General community profiling via denaturing gradient gel electrophoresis of the flaA gene was used to establish the population relationships between various farming practices on representative Campylobacter isolates. The farming practice choices did not influence the high caeca Campylobacter levels (log 7.5 to log 8.5 CFU/g), the carcass levels (log 2.5 to log 3.2 CFU/carcass), the C. jejuni/C. coli dominance and the on-farm bacteriophage presence/levels. A principal coordinate analysis of the flaA distribution for farm and litter practices showed strong separation but no obvious farming practice related grouping of Campylobacter. Bacteriophages originated from select farms, were not practice-dependent, and were detected in the environment (litter) only if present in the birds (caeca). This multifaceted study showed no influence of farming practices on on-farm Campylobacter dynamics. The significance of this study means that a unified on-farm risk-management could be adopted irrespective of commercial practice choices to collectively address caeca Campylobacter levels, as well as the potential to include Campylobacter bacteriophage biocontrol. The impact of this study means that there are no constraints in re-using bedding or adopting free-range farming, thus contributing to environmentally sustainable (re-use) and emerging (free-range) broiler farming choices.

Effects of Dietary Lycopene on the Growth Performance, Antioxidant Capacity, Meat Quality, Intestine Histomorphology, and Cecal Microbiota in Broiler Chickens

The experiment aimed to investigate the effects of dietary lycopene on the growth performance, antioxidant capacity, meat quality, intestine histomorphology, and cecal microbiota in broiler chickens. We randomly divided five hundred and seventy-six one-day-old male broilers into four groups each with six replicates and 24 chickens in each replicate. The control group (CG) was fed the basal diet, and the other groups were given powder lycopene of 10, 20, and 30 mg/kg lycopene (LP10, LP20, and LP30, respectively). Compared with the control group, (1) the dietary lycopene increased (p = 0.001) the average daily gain and decreased (p = 0.033) the feed conversion ratio in the experimental groups; (2) the glutathione peroxidase enzyme contents in LP20 were higher (p =< 0.001) in myocardium; (3) the crude protein contents were higher (p = 0.007) in the group treated with 30 mg/kg dietary lycopene; (4) the jejunum villous height was higher (p = 0.040) in LP20; (5) the Unclassified-f-Ruminococcaceae relative abundance was significantly higher (p = 0.043) in LP20. In this study, adding 20 mg/kg dietary lycopene to the broiler chickens' diets improved the growth performance, antioxidant capacity, meat quality, intestine histomorphology, and cecal microbiota in broiler chickens.

Prevalence of Campylobacter spp., Salmonella spp., and Listeria monocytogenes, and Population Levels of Food Safety Indicator Microorganisms in Retail Raw Chicken Meat and Ready-To-Eat Fresh Leafy Greens Salads Sold in Greece

The presence of microbial pathogens in foods compromises their safety resulting in foodborne illnesses, public health disorders, product recalls, and economic losses. In this work, 60 samples of chilled raw chicken meat and 40 samples of packaged ready-to-eat (RTE) fresh leafy greens salads, sold in Greek retail stores (butchers and supermarkets), were analyzed for the presence of three important foodborne pathogenic bacteria, i.e., Campylobacter spp., Salmonella spp., and Listeria monocytogenes, following the detection protocols of the International Organization for Standardization (ISO). In parallel, the total aerobic plate count (APC), Enterobacteriaceae, total coliforms, Escherichia coli, and staphylococci were also enumerated as hygiene (safety) indicator organisms. When present, representative typical colonies for each pathogen were biochemically verified, following the ISO guidelines. At the same time, all the Campylobacter isolates from chicken (n = 120) were identified to the species level and further phylogenetically discriminated through multiplex and repetitive sequence-based (rep) polymerase chain reaction (PCR) methods, respectively. Concerning raw chicken, Campylobacter spp. were recovered from 54 samples (90.0%) and Salmonella spp. were recovered from 9 samples (15.0%), while L. monocytogenes was present in 35 samples (58.3%). No Campylobacter was recovered from salads, and Salmonella was present in only one sample (2.5%), while three salads were found to be contaminated with L. monocytogenes (7.5%). The 65% of the Campylobacter chicken isolates belonged to C. jejuni, whereas the rest, 35%, belonged to C. coli. Alarmingly, APC was equal to or above 106 CFU/g in 53.3% and 95.0% of chicken and salad samples, respectively, while the populations of some of the other safety indicators were in some cases also high. In sum, this study unravels high occurrence percentages for some pathogenic and food safety indicator microorganisms in raw chicken meat and RTE fresh leafy greens salads sold in Greek retail, highlighting the need for more extensive microbiological control throughout the food production chain (from the farm/field to the market).

Impact of In-Feed versus In-Water Chlortetracycline and Tiamulin Administrations on Fecal Prevalence and Antimicrobial Susceptibilities of Campylobacter in a Population of Nursery Pigs

Antimicrobial resistance (AMR) in bacteria is a major public health concern in the US and around the world. Campylobacter is an important foodborne pathogen that resides in the gut of pigs and is shed in feces, with the potential to be transmitted to humans. In pigs, the oral route, either in-feed or in-water, is by far the most common route of administration of antimicrobials. Because the distribution of the antibiotic in the gut and the dosages are different, the impact of in-feed vs. in-water administration of antibiotics on the development of AMR is likely to be different. Therefore, a study was conducted to compare in-feed vs. in-water administrations of chlortetracycline (CTC) and/or tiamulin on fecal prevalence and AMR profiles of Campylobacter among weaned nursery piglets. A total of 1,296 weaned piglets, allocated into 48 pens (27 piglets per pen), were assigned randomly to six treatment groups: Control (no antibiotic), in-feed CTC, in-water CTC, in-feed tiamulin, in-water tiamulin, or in-feed CTC and tiamulin. Fecal samples were collected randomly from 5 piglets from each pen during the pre-treatment (days 0, 7), treatment (days 14, 21), and post-treatment (days 28, 35) phases. Bacterial isolations and species identifications were conducted by culture and PCR, respectively. The microbroth dilution method with SensititreTM plates was used to determine the antimicrobial susceptibility and resistance of Campylobacter isolates. The results on resistance were interpreted based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cutoff values for Campylobacter. The overall prevalence of Campylobacter was 18.2% (262/1440). Speciation of Campylobacter isolates by PCR indicated the prevalence of only two species: Campylobacter hyointestinalis (17.9%; 258/1440) and C. coli (0.3%; 4/1440). Campylobacter isolates were resistant to tetracycline (98.5%), ciprofloxacin (89.3%), and nalidixic acid (60.3%). Neither the antibiotic nor the route of administration had an effect (p > 0.05) on the prevalence of AMR Campylobacter in the feces of piglets.

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.

Evaluation of Hygiene Practice for Reducing Campylobacter Contamination on Cutting Boards and Risks Associated with Chicken Handling in Kitchen Environment

Cutting boards can serve as potential carriers for the cross-contamination of pathogens from chicken to other surfaces. This study aimed to assess chefs' handling practices of cutting boards across five provinces in China and identify the key factors contributing to unsafe cutting board usage, including cleaning methods and handling practices. Handling practices associated with cutting boards were examined through a web-based survey (N = 154), while kitchen environment tests were conducted to investigate the splashing or survival of Campylobacter, inoculated in chicken or on cutting boards, to mimic the practices of chefs. Among chefs in the five provinces of China, wood and plastic cutting boards were the most commonly used for preparing chicken meat. Approximately 33.7% of chefs washed boards with running tap water, 31.17% of chefs washed boards with detergent, and 24.03% of chefs cleaned boards by scraping them with a knife after preparing other meats or chicken. The study tested 23 cutting boards from commercial kitchens for Campylobacter presence before and after chicken preparation and cleaning. Among these, 17 were cleaned with a knife, 5 with running tap water, and only 1 with disinfectant. Results showed that cleaning with a knife significantly reduced Campylobacter presence on cutting boards (p < 0.05), while the three main cleaning methods were inadequate in eliminating contamination to a safe level. In kitchen environment tests, contaminated chicken was chopped on cutting boards, with a maximum distance of 60 cm for low contamination, and 120 cm for medium and high contamination levels. This suggested a contamination risk exposure area ranging from 60 cm to 120 cm. Campylobacter survival on surfaces of wood, plastic, and stainless steel was also tested, with plastic surfaces showing the longest survival time (4.5 h at 15 °C and 3.5 h at 25 °C) In comparison, survival time on stainless steel or wood surfaces was only 3 h, implying a cross-contamination risk exposure period of 3 to 4.5 h after chicken preparation. In conclusion, based on the current study data, the practices employed by chefs play an important role in Campylobacter transfer in the kitchen environment. The presence of Campylobacter on cutting boards even after wiping or droplet splashing highlights its potential as a source of cross-contamination in the kitchen environment. So, chefs in China should reinforce their hygiene culture and adopt effective cutting board cleaning practices to prevent pathogen contamination.

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Molecular Targets in Campylobacter Infections

Human campylobacteriosis results from foodborne infections with Campylobacter bacteria such as Campylobacter jejuni and Campylobacter coli, and represents a leading cause of bacterial gastroenteritis worldwide. After consumption of contaminated poultry meat, constituting the major source of pathogenic transfer to humans, infected patients develop abdominal pain and diarrhea. Post-infectious disorders following acute enteritis may occur and affect the nervous system, the joints or the intestines. Immunocompromising comorbidities in infected patients favor bacteremia, leading to vascular inflammation and septicemia. Prevention of human infection is achieved by hygiene measures focusing on the reduction of pathogenic food contamination. Molecular targets for the treatment and prevention of campylobacteriosis include bacterial pathogenicity and virulence factors involved in motility, adhesion, invasion, oxygen detoxification, acid resistance and biofilm formation. This repertoire of intervention measures has recently been completed by drugs dampening the pro-inflammatory immune responses induced by the Campylobacter endotoxin lipo-oligosaccharide. Novel pharmaceutical strategies will combine anti-pathogenic and anti-inflammatory effects to reduce the risk of both anti-microbial resistance and post-infectious sequelae of acute enteritis. Novel strategies and actual trends in the combat of Campylobacter infections are presented in this review, alongside molecular targets applied for prevention and treatment strategies.

Campylobacter spp. isolated from poultry in Iran: Antibiotic resistance profiles, virulence genes, and molecular mechanisms

Campylobacter spp. genera is one of the most common causes of microbial enteritis worldwide. The objective of this work was to investigate the antimicrobial resistance (AMR) patterns, virulence genes, and genetic variation of thermophilic Campylobacter species collected from chicken meat samples in Iran. A total of 255 meat specimens were taken and transferred to the laboratory. Culture methods were utilized to identify the Campylobacter genus, and PCR and sequencing were performed to confirm the organisms. Antimicrobial susceptibility evaluation was performed using broth microdilution for six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin (ERY), tetracycline (TET), and gentamicin (GEN)]. By using PCR, AMR and virulence genes were detected. The detection rate of Campylobacter spp. was 64 (25.09%) out of 255 meat samples, with C. jejuni and C. coli accounting for 41 (64.06%) and 14 (21.87%), respectively. Other Campylobacter isolates accounted for 14.06% of the total (nine samples). The antibiotic susceptibility of all Campylobacter isolates was tested using six antibiotics, and all (100%) were resistant to CIP and NAL. However, TET resistance was observed in 93.9% and 83.3% of C. jejuni and C. coli isolates, respectively. Four (8.2%) C. jejuni isolates were multidrug-resistant (MDR), while none of the C. coli isolates were MDR. Two of the four MDR isolates were resistant to CIP, NAL, TET, and ERY, whereas the other two isolates were resistant to CIP, NAL, TET, and GEN. The values of the Minimum Inhibitory Concentration (MIC) were as follows: CIP, 64-256 μg/ml; NAL, 128-512 μg/ml; TET, 2-1024 μg/ml; SIT, 0.25-1 μg/ml; ERY, 1-32 μg/ml; and GEN, 1-256 μg/ml. recR, dnaJ, cdtC, cdtB, cdtA, flaA, ciaB, cadF, and pidA were discovered in more than 50% of C. jejuni isolates, although wlaN, virbll, cgtB, and ceuE were found in <50%. flaA, cadF, pidA, and ciaB were discovered in more than 50% of the C. coli samples, whereas recR, cdtC, cdtB, cdtA, and cgtB were found in less than half. For C. coli, the percentages for wlaN, dnaJ, virbll, and ceuE were all zero. The results of this study show Campylobacter isolates obtained from poultry have higher resistance to quinolones and TET, pathogenicity potential, and varied genotypes.

Intervention Strategies to Control Campylobacter at Different Stages of the Food Chain

Campylobacter is one of the most common bacterial pathogens of food safety concern. Campylobacter jejuni infects chickens by 2-3 weeks of age and colonized chickens carry a high C. jejuni load in their gut without developing clinical disease. Contamination of meat products by gut contents is difficult to prevent because of the high numbers of C. jejuni in the gut, and the large percentage of birds infected. Therefore, effective intervention strategies to limit human infections of C. jejuni should prioritize the control of pathogen transmission along the food supply chain. To this end, there have been ongoing efforts to develop innovative ways to control foodborne pathogens in poultry to meet the growing customers' demand for poultry meat that is free of foodborne pathogens. In this review, we discuss various approaches that are being undertaken to reduce Campylobacter load in live chickens (pre-harvest) and in carcasses (post-harvest). We also provide some insights into optimization of these approaches, which could potentially help improve the pre- and post-harvest practices for better control of Campylobacter.

Olive Leaf as a Source of Antibacterial Compounds Active against Antibiotic-Resistant Strains of Campylobacter jejuni and Campylobacter coli

Campylobacter spp. are the main cause of bacterial gastroenteritis worldwide, and broiler chicks are the main vector of transmission to humans. The high prevalence of Campylobacter in poultry meat and the increase of antibiotic resistant strains have raised the need to identify new antimicrobial agents. For this reason, the aim of the current study was to evaluate the antibacterial activity of two extracts of olive leaf against antibiotic-resistant Campylobacter strains (C. jejuni and C. coli) isolated from poultry food chain. The extracts of olive leaf (E1 and E2) were markedly different in their chemical compositions. While E1 was composed predominantly of highly hydrophilic compounds such as hydroxytyrosol and hydroxytyrosol glucosides (14,708 mg/100 g), E2 mainly contained moderately hydrophilic compounds, with oleuropein (20,471 mg/100 g) being prevalent. All Campylobacter strains exhibited similar antibiotic profiles, being resistant to ciprofloxacin and tetracycline. E1 showed strong antibacterial activity and reduced bacterial growth from 4.12 to 8.14 log CFU/mL, depending on the strain. Hydroxytyrosol was the main compound responsible, causing the inhibition of growth of Campylobacter strains at low concentrations (0.1-0.25 mg/mL). E2 demonstrated a lower antibacterial effect than E1, reducing growth from 0.52 to 2.49 log CFU/mL. The results of this study suggest that the optimization of the composition of olive-leaf extracts can provide improved treatment results against Campylobacter strains.

Review of major meat-borne zoonotic bacterial pathogens

The importance of meat-borne pathogens to global disease transmission and food safety is significant for public health. These pathogens, which can cause a variety of diseases, include bacteria, viruses, fungi, and parasites. The consumption of pathogen-contaminated meat or meat products causes a variety of diseases, including gastrointestinal ailments. Humans are susceptible to several diseases caused by zoonotic bacterial pathogens transmitted through meat consumption, most of which damage the digestive system. These illnesses are widespread worldwide, with the majority of the burden borne by developing countries. Various production, processing, transportation, and food preparation stages can expose meat and meat products to bacterial infections and/or toxins. Worldwide, bacterial meat-borne diseases are caused by strains of Escherichia coli, Salmonella, Listeria monocytogenes, Shigella, Campylobacter, Brucella, Mycobacterium bovis, and toxins produced by Staphylococcus aureus, Clostridium species, and Bacillus cereus. Additionally, consuming contaminated meat or meat products with drug-resistant bacteria is a severe public health hazard. Controlling zoonotic bacterial pathogens demands intervention at the interface between humans, animals, and their environments. This review aimed to highlight the significance of meat-borne bacterial zoonotic pathogens while adhering to the One Health approach for creating efficient control measures.

Genomic Diversity of Campylobacter lari Group Isolates from Europe and Australia in a One Health Context

Members of the Campylobacter lari group are causative agents of human gastroenteritis and are frequently found in shellfish, marine waters, shorebirds, and marine mammals. Within a One Health context, we used comparative genomics to characterize isolates from a diverse range of sources and geographical locations within Europe and Australia and assess possible transmission of food, animal, and environmental isolates to the human host. A total of 158 C. lari isolates from Australia, Denmark, France, and Germany, which included 82 isolates from human stool and blood, 12 from food, 14 from domestic animal, 19 from waterbirds, and 31 from the environment were analyzed. Genome-wide analysis of the genetic diversity, virulence, and antimicrobial resistance (AMR) traits was carried-out. Most of the isolates belonged to C. lari subsp. lari (Cll; 98, 62.0%), while C. lari subsp. concheus and C. lari urease-positive thermotolerant Campylobacter (UPTC) were represented by 12 (7.6%) and 15 (9.5%) isolates, respectively. Furthermore, 33 (20.9%) isolates were not assigned a subspecies and were thus attributed to distant Campylobacter spp. clades. Whole-genome sequence-derived multilocus sequence typing (MLST) and core-genome MLST (cgMLST) analyses revealed a high genetic diversity with 97 sequence types (STs), including 60 novel STs and 14 cgMLST clusters (≤10 allele differences), respectively. The most prevalent STs were ST-21, ST-70, ST-24, and ST-58 (accounting for 13.3%, 4.4%, 3.8%, and 3.2% of isolates, respectively). A high prevalence of the 125 examined virulence-related loci (from 76.8 to 98.4% per isolate) was observed, especially in Cll isolates, suggesting a probable human pathogenicity of these strains. IMPORTANCE Currently, relatedness between bacterial isolates impacting human health is easily monitored by molecular typing methods. These approaches rely on discrete loci or whole-genome sequence (WGS) analyses. Campylobacter lari is an emergent human pathogen isolated from diverse ecological niches, including fecal material from humans and animals, aquatic environments, and seafood. The presence of C. lari in such diverse sources underlines the importance of adopting an integrated One Health approach in studying C. lari population structure for conducting epidemiological risk assessment. This retrospective study presents a comparative genomics analysis of C. lari isolates retrieved from two different continents (Europe and Australia) and from different sources (human, domestic animals, waterbirds, food, and environment). It was designed to improve knowledge regarding C. lari ecology and pathogenicity, important for developing effective surveillance and disease prevention strategies.

Prevalence, antimicrobial resistance, virulence gene profile and molecular typing of Campylobacter species isolated from poultry meat samples

BACKGROUND

Campylobacter jejuni and Campylobacter coli are the most significant Campylobacter species responsible for severe gastrointestinal disorders. Raw poultry meat is considered a source of Campylobacter transmission to the human population.

OBJECTIVES

The present study was aimed to assess the prevalence rate, antibiotic resistance properties, virulence characters and molecular typing of C. jejuni and C. coli strains isolated from raw poultry meat samples.

METHODS

Three hundred and eighty raw poultry meat samples were collected and analysed for the presence of Campylobacter spp. using the microbial culture. Species identification was done using the Polymerase Chain Reaction. Disk diffusion was developed to assess the antimicrobial resistance pattern of isolates. The distribution of virulence and antimicrobial resistance genes was determined by PCR. Enterobacterial Repetitive Intergenic Consensus-PCR was used for molecular typing.

RESULTS

Campylobacter species were isolated from 6.25% of examined samples. C. jejuni and C. coli contamination rates were found to be 57.44% and 48.14%, respectively. C. jejuni strains harboured the highest resistance rate against serythromycin (42.59%), ampicillin (38.88%), ciprofloxacin (33.33%), chloramphenicol (31.48%) and tetracycline (31.48%). C. coli isolates harboured the highest resistance rate against ampicillin (73.07%), ciprofloxacin (73.07%), erythromycin (65.38%) and chloramphenicol (50%). AadE1 (44.44%), blaOXA-61 (42.59%) and tet(O) (35.18%) were the most commonly detected resistance genes in C. jejuni and cmeB (34.61%) and blaOXA-61 (34.61%) were the most commonly detected among C. coli strains. The most frequent virulence factors among the C. jejuni isolates were flaA (100%), ciaB (100%), racR (83.33%), dnaJ (81.48%), cdtB (81.48%), cdtC (79.62%) and cadF (74.07%). The most frequent virulence factors among the C. coli isolates were flaA (100%), ciaB (100%), pldA (65.38%) and cadF (61.53%).

CONCLUSIONS

The majority of C. jejuni and C. coli strains had more than 80% similarities in their ERIC-PCR pattern, which may show their common source of transmission. The role of goose and quebec meat samples as reservoirs of virulent and antimicrobial resistant Campylobacter spp. was determined.

Genomic diversity, virulence and source of Campylobacter jejuni contamination in Irish poultry slaughterhouses by whole genome sequencing

AIMS

The aim was to exploit whole genome sequencing (WGS) to assess genomic diversity, identify virulence genes and deduce the proportion of Campylobacter colonized broilers that directly contaminate their carcasses.

METHODS AND RESULTS

Campylobacter jejuni isolates (107) from caeca and carcass neck skin samples (50 pairs from the same batch plus 7 individual caeca) sampled at three poultry slaughterhouses over a one-year period were selected for sequencing (MiSeq; Illumina). FastQ files were submitted to BioNumerics for analysis using the wgMLST scheme for allele calling. Campylobacter cgMLST and hierarchical clustering was performed by applying the single linkage algorithm. Sequence types (STs) were determined in silico from the WGS data and isolates were assigned into clonal complexes (CCs) using the Campylobacter PubMLST.org database. Virulence genes were determined by downloading core sequences from the virulence factor database (VFDB) and the National Center for Biotechnology Information (NCBI). A high degree of diversity was observed with 23 different STs identified. ST257 and CC-21 were the most common STs and CCs, respectively. cgMLST analysis suggested that 56% of carcass contamination was a direct result of contamination from caeca from the same batch. Virulence genes known to play a role in human C. jejuni infection were identified such as the wlaN gene and the genes associated with lipooligosaccharide synthesis, which were identified in 30% of isolates.

CONCLUSIONS

Caecal colonization was the more plausible occurring source of C. jejuni contamination of broiler carcasses, compared with cross-contamination from another batch or the environment. The high rate of genetic diversity observed amongst caecal isolates is consistent with a wide variety of Campylobacter strains circulating in poultry flocks in Ireland.

SIGNIFICANCE AND IMPACT OF STUDY

The results will further inform broiler processors and regulators about the influence and importance of on-farm colonization versus slaughterhouse cross-contamination and the relationship between C. jejuni in caeca and carcasses during processing.

Roles of Aerotolerance, Biofilm Formation, and Viable but Non-Culturable State in the Survival of Campylobacter jejuni in Poultry Processing Environments

Campylobacter jejuni is one of the most common causes of foodborne human gastroenteritis in the developed world. This bacterium colonizes in the ceca of chickens, spreads throughout the poultry production chain, and contaminates poultry products. Despite numerous on farm intervention strategies and developments in post-harvest antimicrobial treatments, C. jejuni is frequently detected on broiler meat products. This indicates that C. jejuni is evolving over time to overcome the stresses/interventions that are present throughout poultry production and processing. The development of aerotolerance has been reported to be a major survival strategy used by C. jejuni in high oxygen environments. Recent studies have indicated that C. jejuni can enter a viable but non-culturable (VBNC) state or develop biofilm in response to environmental stressors such as refrigeration and freezing stress and aerobic stress. This review provides an overview of different stressors that C. jejuni are exposed to throughout the poultry production chain and the genotypic and phenotypic survival mechanisms, with special attention to aerotolerance, biofilm formation, and development of the VBNC state.

Feed Safety and the Development of Poultry Intestinal Microbiota

Simple Summary

Intensive gut colonisation of animals starts immediately after birth or hatch. Oral route of colonisation, and consequently the first feed, plays a significant role in the continual defining of the intestinal microbial community. The feed can influence colonisation in two ways: providing the microbial inoculum and providing the nutritional requirements that suit a specific type of microbes. In combination with environmental factors, feed shapes animal’s future health and performance from the first day of life. The objective of this review was to investigate feed safety aspects of animal nutrition from the gut colonisation aspect.

Abstract

The first feed offered to young chicks is likely the most important meal in their life. The complex gut colonisation process is determined with early exposure and during the first days of life before the microbial community is formed. Therefore, providing access to high-quality feed and an environment enriched in the beneficial and deprived of pathogenic microorganisms during this period is critical. Feed often carries a complex microbial community that can contain major poultry pathogens and a range of chemical contaminants such as heavy metals, mycotoxins, pesticides and herbicides, which, although present in minute amounts, can have a profound effect on the development of the microbial community and have a permanent effect on bird’s overall health and performance. The magnitude of their interference with gut colonisation in livestock is yet to be determined. Here, we present the animal feed quality issues that can significantly influence the microbial community development, thus severely affecting the bird’s health and performance.

Anti-Campylobacter Probiotics: Latest Mechanistic Insights

The Campylobacter genus is the leading cause of human gastroenteritis, with the consumption of contaminated poultry meat as the main route of infection. Probiotic bacteria, such as Lactobacillus, Bacillus, Escherichia coli Nissle, and Bifidobacterium species, have a great immunomodulatory capacity and exhibit antipathogenic effects through various molecular mechanisms. Reducing Campylobacter levels in livestock animals, such as poultry, will have a substantial benefit to humans as it will reduce disease transmissibility through the food chain. Moreover, probiotic-based strategies might attenuate intestinal inflammatory processes, which consequently reduce the severity of Campylobacter disease progression. At a molecular level, probiotics can also negatively impact on the functionality of various Campylobacter virulence and survival factors (e.g., adhesion, invasion), and on the associated colonization proteins involved in epithelial translocation. The current review describes recent in vitro, in vivo, and preclinical findings on probiotic therapies, aiming to reduce Campylobacter counts in poultry and reduce the pathogen's virulence in the avian and human host. Moreover, we focused in particular on probiotics with known anti-Campylobacter activity seeking to understand the biological mechanisms involved in their mode of action.

Occurrence and Multidrug Resistance of Campylobacter in Chicken Meat from Different Production Systems

Campylobacter is the leading bacterial cause of diarrheal disease worldwide and poultry remains the primary vehicle of its transmission to humans. Due to the rapid increase in antibiotic resistance among Campylobacter strains, the World Health Organization (WHO) added Campylobacter fluoroquinolone resistance to the WHO list of antibiotic-resistant "priority pathogens". This study aimed to investigate the occurrence and antibiotic resistance of Campylobacter spp. in meat samples from chickens reared in different production systems: (a) conventional, (b) free-range and (c) backyard farming. Campylobacter spp. was detected in all samples from conventionally reared and free-range broilers and in 72.7% of backyard chicken samples. Levels of contamination were on average 2.7 × 103 colony forming units (CFU)/g, 4.4 × 102 CFU/g and 4.2 × 104 CFU/g in conventionally reared, free-range and backyard chickens, respectively. Campylobacter jejuni and Campylobacter coli were the only species isolated. Distribution of these species does not seem to be affected by the production system. The overall prevalence of Campylobacter isolates exhibiting resistance to at least one antimicrobial was 98.4%. All the C. coli isolates showed resistance to ciprofloxacin and to nalidixic acid, and 79.5 and 97.4% to ampicillin and tetracycline, respectively. In total, 96.2% of C. jejuni isolates displayed a resistant phenotype to ciprofloxacin and to nalidixic acid, and 92.3% to ampicillin and tetracycline. Of the 130 Campylobacter isolates tested, 97.7% were classified as multidrug resistant (MDR).

Selected Livestock-Associated Zoonoses as a Growing Challenge for Public Health

The aim of this paper is to review the most significant livestock-associated zoonoses. Human and animal health are intimately connected. This idea has been known for more than a century but now it has gained special importance because of the increasing threat from zoonoses. Zoonosis is defined as any infection naturally transmissible from vertebrate animals to humans. As the frequency and prevalence of zoonotic diseases increase worldwide, they become a real threat to public health. In addition, many of the newly discovered diseases have a zoonotic origin. Due to globalization and urbanization, some of these diseases have already spread all over the world, caused by the international flow of goods, people, and animals. However, special attention should be paid to farm animals since, apart from the direct contact, humans consume their products, such as meat, eggs, and milk. Therefore, zoonoses such as salmonellosis, campylobacteriosis, tuberculosis, swine and avian influenza, Q fever, brucellosis, STEC infections, and listeriosis are crucial for both veterinary and human medicine. Consequently, in the suspicion of any zoonoses outbreak, the medical and veterinary services should closely cooperate to protect the public health.

Development and Evaluation of Fluorescence Immunochromatography for Rapid and Sensitive Detection of Thermophilic Campylobacter

Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) are leading causes of foodborne gastroenteritis in Japan. Epidemiological surveillance has provided evidence that poultry meat is one of the main reservoirs for human campylobacteriosis, and therefore, improvement in process hygiene at slaughter is required to reduce the number of human infections. This study thus aimed to develop fluorescent immunochromatography strips for rapid and sensitive detection of thermophilic Campylobacter on poultry carcasses at slaughter. To establish the required detection levels, we first determined the numbers of C. jejuni and C. coli on poultry carcasses at one large-scale poultry slaughterhouse in Japan, resulting in the detection of Campylobacter at 1.97 ± 0.24 log CFU/25 g of neck skin during the post-chilling process by using ISO 10272-2:2017. Our developed Campylobacter fluorescence immunochromatography (FIC) assay exhibited a 50% limit of detection of 3.51 log CFU or 4.34 log CFU for C. jejuni NCTC 11168 or C. coli JCM 2529, respectively. Inclusive and exclusive tests resulted in good agreement. The practical usefulness of this test toward poultry carcasses should be evaluated in future studies, perhaps concentration of the target microorganisms prior to the testing might be helpful to further enhance sensitivity. Nevertheless, our data suggest the potential of FIC for rapid and sensitive detection of thermophilic Campylobacter for monitoring the process hygiene of poultry carcasses at slaughter.

Conjugative Plasmid-Mediated Extended Spectrum Cephalosporin Resistance in Genetically Diverse Escherichia coli from a Chicken Slaughterhouse

ESC-resistant E. coli isolates were collected from broiler chickens, a slaughterhouse, and retail meat to assess their dispersion and their involvement in cross-contamination. ESBL-/AmpC-producing E. coli were isolated during the slaughter process of all six investigated chicken flocks from scalding, feather removal, first conveyor, evisceration, second washing, third conveyor, and third washing areas, and from handling workers in the slaughterhouse. ESC-resistant E. coli isolates with the same pulsed-field gel electrophoresis type were found in the same site (scalding) on different sampling days. ESBL/AmpC-producing E. coli isolates were absent in the lairage area in the slaughterhouse, but present in the retail markets in 36.8% (7/19) of the chicken flocks. The bla_CTX-M genes and bla_CMY-2 were conjugated to recipient E. coli J53 in 67.5% (27/40) and 56.1% (23/41) of ESBL-producing and AmpC-producing E. coli isolates, respectively. The presence of the same conjugative plasmids was found in genetic diversity ESC-resistant E. coli colonies collected on different sampling days. Our study emphasizes that cross-contamination of ESBL/AmpC-producing E. coli in slaughterhouse has a crucial impact on the occurrence of ESC resistance in retail chicken meat.