Jejuni In Chickens Research Articles

Selective depletion of Campylobacter jejuni via T6SS dependent functionality: an approach for improving chickens gut health

The targeted depletion of potential gut pathogens is often challenging because of their intrinsic ability to thrive in harsh gut environments. Earlier, we showed that Campylobacter jejuni (C. jejuni) exclusively uses the Type-VI Secretion System (T6SS) to target its prey such as Escherichia coli (E. coli), and phenotypic differences between T6SS-negative and T6SS-positive C. jejuni isolates toward bile salt sensitivity. However, it remains unclear how the target-driven T6SS functionality prevails in a polymicrobial gut environment. Here, we investigated the fate of microbial competition in an altered gut environment via bacterial T6SS using a T6SS-negative and -positive C. jejuni or its isogenic mutant of the hemolysin-coregulated protein (hcp). We showed that in the presence of bile salt and prey bacteria (E. coli), T6SS-positive C. jejuni experiences enhanced intracellular stress leading to cell death. Intracellular tracking of fluorophore-conjugated bile salts confirmed that T6SS-mediated bile salt influx into C. jejuni can enhance intracellular oxidative stress, affecting C. jejuni viability. We further investigated whether the T6SS activity in the presence of prey (E. coli) perturbs the in vivo colonization of C. jejuni. Using chickens as primary hosts of C. jejuni and non-pathogenic E. coli as prey, we showed a marked reduction of C. jejuni load in chickens cecum when bile salt solution was administered orally. Analysis of local antibody responses and pro-inflammatory gene expression showed a reduced risk of tissue damage, indicating that T6SS activity in the complex gut environment can be exploited as a possible measure to clear the persistent colonization of C. jejuni in chickens.

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

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

El Síndrome de Guillain-Barré en Perú: ¿Dengue y Zika detrás del aumento de casos?

In 2023, Peru experienced the largest dengue outbreak in its history, with over 197,000 confirmed cases. Between epidemiological weeks 23 and 27 of that year, there was a peak in cases of Guillain-Barré syndrome (GBS), just two weeks after the peak of dengue cases. There is previous evidence associating dengue with the development of GBS, suggestingthat the dengue virus may be responsible for many of the current cases. Additionally, there were 31 cases of Zika recorded in Peru in 2023, a neurotropic virus that has also been previously linked to GBS. While there has been speculation in some media about the current GBS outbreak being related to Campylobacter jejuni in chickens, there is no conclusive evidence supporting this claim. It is necessary to conduct in-depth investigations into the presence of dengue and Zika in samples from patients with GBS to understand the potential causal role of these viruses. Studying the relationship between these infectious agents and the development of GBS can enhance prevention and treatment strategies for future epidemiological threats.

Genetic Signature and Serocompatibility Evidence for Drug Resistant Campylobacter jejuni.

Campylobacteriosis, a foodborne illness, is one of the world′s leading causes of gastrointestinal illness. This study investigates the link between human campylobacteriosis and the consumption of potentially contaminated food with Campylobacter jejuni. Three hundred sixty samples were collected from humans, chicken cloaca, raw chicken meat, unpasteurized milk, and vegetables. The chickens were obtained from licensed and non-licensed slaughterhouses, and only the necks and wings were studied. Samples were enriched under microaerobic conditions then cultured on the modified charcoal cefoperazone deoxycholate agar. Bacteria was identified by staining, biochemical testing, and molecular identification by the polymerase chain reaction for the virulence genes; hipO, asp, dnaJ, cadF, cdtA, cdtB, and cdtC. The genomic homogeneity of C. jejuni between human and chicken isolates was assessed by the serological Penner test and the pulse field gel electrophoresis (PFGE). Campylobacter was not detected in the vegetables and pasteurized milk, though, only twenty isolates from chickens and clinical samples were presumed to be Campylobacter based on their morphology. The biochemical tests confirmed that five isolates were C. coli, and fifteen isolates were C. jejuni including two isolates from humans, and the remaining were from chickens. The colonization of C. jejuni in chickens was significantly lower in necks (6.66%) obtained from licensed slaughterhouses compared to those obtained from non-licensed slaughterhouses (33.3%). The antimicrobial susceptibility test showed that all identified C. jejuni isolates were resistant to antibiotics, and the majority of isolates (53.5%) showed resistance against six antibiotics, though, all isolates were resistant to ciprofloxacin, tetracycline, and aztreonam. The Penner test showed P:21 as the dominant serotype in isolates from humans, necks, and cloaca. The serohomology of C. jejuni from human isolates and chicken necks, wings, and cloaca was 71%, 36%, 78%, respectively. The PFGE analysis of the pattern for DNA fragmentation by the restriction enzyme Smal showed a complete genotypic homology of C. jejuni human isolates and chicken necks compared to partial homology with cloacal isolates. The study brings attention to the need for effective interventions to ensure best practices for safe poultry production for commercial food chain supply to limit infection with foodborne pathogens, including Campylobacter.

Microbiota from Specific Pathogen-Free Mice Reduces Campylobacter jejuni Chicken Colonization.

Campylobacter jejuni, a prevalent foodborne bacterial pathogen, is mainly transmitted from poultry with few effective prevention approaches. In this study, we aimed to investigate the role of microbiota on C. jejuni chicken colonization. Microbiota from specific pathogen-free (SPF) mouse stools were collected as SPF-Aerobe and SPF-Anaerobe. Birds were colonized with SPF-Aerobe or SPF-Anaerobe at day 0 and infected with C. jejuni AR101 at day 12. Notably, C. jejuni AR101 colonized at 5.3 and 5.6 log10 C. jejuni CFU/g chicken cecal digesta at days 21 and 28, respectively, while both SPF-Aerobe and SPF-Anaerobe microbiota reduced pathogen colonization. Notably, SPF-Aerobe and SPF-Anaerobe increased cecal phylum Bacteroidetes and reduced phylum Firmicutes compared to those in the nontransplanted birds. Interestingly, microbiota from noninfected chickens, SPF-Aerobe, or SPF-Anaerobe inhibited AR101 in vitro growth, whereas microbiota from infected birds alone failed to reduce pathogen growth. The bacterium Enterobacter102 isolated from infected birds transplanted with SPF-Aerobe inhibited AR101 in vitro growth and reduced pathogen gut colonization in chickens. Together, SPF mouse microbiota was able to colonize chicken gut and reduce C. jejuni chicken colonization. The findings may help the development of effective strategies to reduce C. jejuni chicken contamination and campylobacteriosis.

Controlling Campylobacter jejuni in vitro and in chicken using combinations of citrus‐based and trisodium phosphate formulations

AbstractCampylobacter frequently contaminates chicken. Trisodium phosphate (TSP) is used for chicken decontamination; however, reduction of chemical preservatives is desirable. This study analyzed the efficacy of two commercial citrus‐based products (CitroSan [CS] and Citrol‐K Ultra [CK]) alone and in combination with TSP for reduction of Campylobacter in vitro and in chicken. The minimum bactericidal concentration (MBC) of the preservatives alone or in combination was determined against Campylobacter jejuni. Their ability to reduce bacteria in raw chicken and their effect on the sensorial characteristics of the meat were determined. The MBCs obtained were 0.5 ± 0.04% for TSP, 0.05 ± 0.0006% for CS, and 0.0006 ± 0.0001% for CK. When combined, bactericidal concentrations varied. Following contact with TSP–CS and TSP–CK for 6 hr, C. jejuni was reduced from 106 to &lt;100 CFU/g. Concentrations below those used in industry (2% TSP, 0.3% CS, and 0.05% CK) were added on the raw chicken skin before (B: treated with TSP and then inoculated) and after (A: inoculated and then treated with TSP) inoculation of Campylobacter. TSP (A) reduced C. jejuni by 92.6% after 24 hr, whereas TSP (B) caused a 36% reduction. TSP (A and B) in combination with both CS and CK caused 98.9 and 95.9% reduction, respectively, after 120 hr. The CS–CK combination (without TSP) reduced bacteria to undetectable levels after 48 hr. No significant differences were detected in the sensorial characteristics of treated wings. All the combinations tested, but especially 0.3% TSP + 0.0003% CK represent alternatives to control C. jejuni in chicken and reduce or avoid synthetic preservatives.

Survival of Campylobacter jejuni in chicken at refrigeration and cooking temperatures

Abstract: The objective of this work was to evaluate the reduction of Campylobacter jejuni in chicken meat at 6 and 70°C, after the inoculation of a Brazilian strain. The kinetics of C. jejuni survival showed a 0.26 log (CFU g-1) decrease for each day of exposure at 6°C, and a 1.35 log (CFU g-1) decrease for each 1 log increase at 70°C. Although reduced levels of C. jejuni were found after regular intervals at both temperatures, its incomplete inactivation underlines the need of good hygiene practices for consumers to avoid campylobacteriosis.

Prevalence, Antimicrobial Susceptibility, Virulence and Genotyping of Campylobacter jejuni with a Special Reference to the Anti-Virulence Potential of Eugenol and Beta-Resorcylic Acid on Some Multi-Drug Resistant Isolates in Egypt

Simple SummaryCampylobacter jejuni is the main reason for human foodborne bacterial enteritis globally. Contaminated chickens and their products are the principal reservoirs of C. jejuni and they are responsible for up to 80% of human campylobacter infection cases. In the current study, we determined the prevalence, antibiogram, the virulence factors encoding genes, and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) profiles of C. jejuni isolated from chicken and human in Egypt, and we also assessed the effects of two phytochemicals (eugenol and beta-resorcylic acid) on the virulence of avian multi-drug resistant (MDR) and multi-virulent C. jejuni isolates. Our results revealed high prevalence of C. jejuni isolates (32.8%), and all isolates were MDR. Chicken and human C. jejuni isolates were clustered together as found in ERIC-PCR fingerprinting clusters II–V, which confirmed the genetic relatedness between both origins. Additionally, beta-resorcylic acid and eugenol reduced the invasion of MDR C. jejuni isolates to chicken intestinal epithelial cells and also minimized the transcription of flaA, virB11, and wlaN genes in the tested isolates. In conclusion, eugenol and beta-resorcylic acid could be used for minimizing the colonization and pathogenicity of C. jejuni; therefore, they could be utilized for controlling C. jejuni in broiler chickens and potentially for managing human campylobacteriosis.Campylobacter jejuni is the leading cause of foodborne bacterial gastroenteritis in humans worldwide. Contaminated chickens and their products are the main sources of human campylobacteriosis. Therefore, this study aimed to detect the genotypic and virulence genes‘ profiles of multi-drug resistant (MDR) C. jejuni isolates and to assess the effects of sub-inhibitory concentrations (SICs) of eugenol and beta-resorcylic acid on the virulence of avian MDR C. jejuni isolates. These isolates were clustered together with the human isolates via enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) fingerprinting. A total of 345 samples were collected from human stool (100) and different chicken (245) samples in Sharkia Governorate, Egypt. Conventional phenotypic methods identified 113 isolates (32.8%) as C. jejuni, and all C. jejuni isolates were MDR and resistant to erythromycin and ampicillin. The genes virB11, wlaN, and flaA were detected in 52%, 36% and 100% strains, respectively. ERIC-PCR yielded 14 profiles and five main clusters. Interestingly, human and chicken C. jejuni isolates were clustered together in ERIC-PCR clusters II-V, which confirmed the genetic relatedness between the isolates from both origins. Beta-resorcylic acid and eugenol inhibited the invasion of C. jejuni isolates to chicken intestinal cells by 41.66–38.19% and 31.94–29.16%, respectively, and minimized the transcription of flaA, virB11, and wlaN genes in the tested isolates by real-time quantitative reverse transcription PCR (qRT-PCR). In essence, eugenol and beta-resorcylic acid are promising natural antimicrobials for minimizing the virulence of MDR C. jejuni in chickens, thereby managing human campylobacteriosis.

Effect of Decontamination Treatments on Campylobacter jejuni in Chicken.

The ability of different decontaminating treatments (acetic, citric and fumaric acids, and potassium sorbate) to decrease Campylobacter jejuni on chicken legs was evaluated. Fresh chicken legs were inoculated with C. jejuni and washed with either acetic, citric, or fumaric acid (1% and 2%), or potassium sorbate (1%, 2%, and 5%) solutions or distilled water. Evolution of C. jejuni, Pseudomonas, and Enterobacterales counts, and sensorial acceptability were evaluated after treatment (day 1) and on days 2, 4, 7, and 9 of storage at 4 °C. The lowest Pseudomonas counts were found in those legs dipped in 2% fumaric acid, while the lowest Enterobacterales populations were found in those legs dipped in 2% fumaric or 2% acetic acid. The shelf life of the legs treated was widened by at least 2 days over the control legs. The highest C. jejuni reductions after treatment were obtained in samples dipped in 2% citric acid, which were approximately 2.66 log units lower than in non-treated legs. However, the efficacy of citric acid decreased during storage. After day 2 of storage, the highest reductions of C. jejuni were found in those legs dipped in 2% acetic acid.

Phosphate Transporter PstSCAB of Campylobacter jejuni Is a Critical Determinant of Lactate-Dependent Growth and Colonization in Chickens.

Campylobacter jejuni causes acute gastroenteritis worldwide and is transmitted primarily through poultry, in which it is often a commensal member of the intestinal microbiota. Previous transcriptome sequencing (RNA-Seq) experiment showed that transcripts from an operon encoding a high-affinity phosphate transporter (PstSCAB) of C. jejuni were among the most abundant when the bacterium was grown in chickens. Elevated levels of the pstSCAB mRNA were also identified in an RNA-Seq experiment from human infection studies. In this study, we explore the role of PstSCAB in the biology and colonization potential of C. jejuni Our results demonstrate that cells lacking PstSCAB survive poorly in stationary phase, in nutrient-limiting media, and under osmotic conditions reflective of those in the chicken. Polyphosphate levels in the mutant cells were elevated at stationary phase, consistent with alterations in expression of polyphosphate metabolism genes. The mutant strain was highly attenuated for colonization of newly hatched chicks, with levels of bacteria at several orders of magnitude below wild-type levels. Mutant and wild type grew similarly in complex media, but the pstS::kan mutant exhibited a significant growth defect in minimal medium supplemented with l-lactate, postulated as a carbon source in vivo Poor growth in lactate correlated with diminished expression of acetogenesis pathway genes previously demonstrated as important for colonizing chickens. The phosphate transport system is thus essential for diverse aspects of C. jejuni physiology and in vivo fitness and survival.IMPORTANCECampylobacter jejuni causes millions of human gastrointestinal infections annually, with poultry a major source of infection. Due to the emergence of multidrug resistance in C. jejuni, there is need to identify alternative ways to control this pathogen. Genes encoding the high-affinity phosphate transporter PstSCAB are highly expressed by C. jejuni in chickens and humans. In this study, we address the role of PstSCAB on chicken colonization and other C. jejuni phenotypes. PstSCAB is required for colonization in chicken, metabolism and survival under different stress responses, and during growth on lactate, a potential growth substrate in chickens. Our study highlights that PstSCAB may be an effective target to develop mechanisms for controlling bacterial burden in both chicken and human.

Effect of Lactobacillus spp. on adhesion, invasion, and translocation of Campylobacter jejuni in chicken and pig small-intestinal epithelial cell lines

BackgroundCampylobacter spp. are a major cause of bacterial food-borne diarrhoeal disease. This mainly arises through contamination of meat products during processing. For infection, Campylobacter spp. must adhere to epithelial cells of the mucus layer, survive conditions of the gastrointestinal tract, and colonise the intestine of the host. Addition of probiotic bacteria might promote competitive adhesion to epithelial cells, consequently reducing Campylobacter jejuni colonisation. Effect of Lactobacillus spp. (PCS20, PCS22, PCS25, LGG, PCK9) on C. jejuni adhesion, invasion and translocation in pig (PSI cl.1) and chicken (B1OXI) small-intestine cell lines, as well as pig enterocytes (CLAB) was investigated.ResultsOverall, in competitive adhesion assays with PSI cl.1 and CLAB cell monolayers, the addition of Lactobacillus spp. reduced C. jejuni adherence to the cell surface, and negatively affected the C. jejuni invasion. Interestingly, Lactobacillus spp. significantly impaired C. jejuni adhesion in three-dimensional functional PSI cl.1 and B1OXI cell models. Also, C. jejuni did not translocate across PSI cl.1 and B1OXI cell monolayers when co-incubated with probiotics. Among selected probiotics, Lactobacillus rhamnosus LGG was the strain that reduced adhesion efficacy of C. jejuni most significantly under co-culture conditions.ConclusionThe addition of Lactobacillus spp. to feed additives in livestock nutrition might be an effective novel strategy that targets Campylobacter adhesion to epithelial cells, and thus prevents colonisation, reduces the transmission, and finally lowers the incidence of human campylobacteriosis.

Mucosal delivery of live Lactococcus lactis expressing functionally active JlpA antigen induces potent local immune response and prevent enteric colonization of Campylobacter jejuni in chickens

Successful colonization of the mucosal epithelial cells is the key early step for Campylobacter jejuni (C. jejuni) pathogenesis in humans. A set of Surface Exposed Colonization Proteins (SECPs) are known to take leading role in bacterial adhesion and subsequent host pathogenesis. Among the major SECPs, the constitutively expressed C. jejuni surface lipoprotein Jejuni lipoprotein A (JlpA), interacts with intestinal heat shock protein 90α (Hsp90α) and contributes in disease progression by triggering pro-inflammatory responses via activation of NF-κB and p38 MAP kinase pathways. In addition to its ability to express on the surface, high sequence conservation of JlpA protein among different Campylobacter spp make it a suitable vaccine target against C. jejuni. Given that chickens are the primary source for C. jejuni infection in humans and persistent cecal colonization significantly contribute in pathogen transmission, we explicitly used chickens as a model to test the immune-protective efficacy of JlpA protein. Taking into account that gastro-intestinal tract is the major site for C. jejuni colonization, we chose to use mucosal (intragastric) route as mode for JlpA antigen delivery. To deliver JlpA via mucosal route, we engineered a food grade Lactic acid producing bacteria, Lactococcus lactis (L. lactis) to express functionally active JlpA protein in the surface. Further, we demonstrated its ability to substantially improve the antigen specific local immune responses in the intestine along with significant immune-protection against enteric colonization of C. jejuni in chickens.

Local intestinal immune response including NLRP3 inflammasome in broiler chicken infected with Campylobacter jejuni after administration of Lactobacillus reuteri B1/1

ABSTRACT The aim of this study was to evaluate the influence of Lactobacillus reuteri B1/1 on the local intestinal immune response in the cecum of chickens experimentally infected by C. jejuni CCM6189. Day-old chicken were divided into four groups: control (C), L. reuteri B1/1 (LR), C. jejuni CCM6189 (CJ), and combined L. reuteri B1/1 + C. jejuni CCM6189 (LRCJ). Cecal samples were collected during necropsy 12, 24, 48 hours after infection by C. jejuni (relative expression of NLRP3, caspase-1, interleukins, TLR4) and 4 as well as 7 day post infection (relative percentage of CD4+, CD8+, IgM). L. reuteri B1/1 significantly stimulated gene expression of NLRP3 inflammasome and other selected molecules, thereby increasing the capacity of the immune system to react more effectively to the infection of C. jejuni in chicken. In addition, an increase of IgM and the percentage of CD8+ influenced by L. reuteri was observed.

Beta-lactam resistance in Campylobacter coli and Campylobacter jejuni chicken isolates and the association between blaOXA-61 gene expression and the action of β-lactamase inhibitors

The objectives of this work were to evaluate β-lactamase-mediated β-lactam resistance in Campylobacter coli and Campylobacter jejuni isolates obtained from broiler chickens, expression of the blaOXA-61 gene in relation to β-lactamase production, and the possible association between blaOXA-61 gene expression and the action of inhibitors when combined with β-lactams. All strains were tested by disk diffusion and nitrocefin methods to assess antibiotic susceptibility and β-lactamase production, respectively. PCR and qPCR amplification were performed to evaluate qualitative and quantitative blaOXA-61 expression. Campylobacter spp. showed a high level of resistance to the most of antimicrobials tested. C. coli strains were ampicillin resistant and blaOXA-61 positive, and 59 out of 60 isolates were positive in the nitrocefin test. Twenty C. jejuni isolates were positive for blaOXA-61 and the nitrocefin test, although two isolates were ampicillin sensitive. Amoxicillin/clavulanic acid and ticarcillin/clavulanic acid do not seem to be active against C. coli, as 73.3 %, and 88.3 % of isolates were resistant to amoxicillin/clavulanic acid and ticarcillin/clavulanic acid, respectively. C. jejuni was not susceptible to amoxicillin/clavulanic acid, with 90 % of the strains showing resistance, whereas ticarcillin associated with clavulanic acid was significantly more efficient than ticarcillin alone (P < 0.01), with 90 % of the strains found to be susceptible. An association between blaOXA-61 expression and amoxicillin/clavulanic acid and ticarcillin/clavulanic acid resistance (P = 0.0001) was seen in C. coli, as well as in C. jejuni for ampicillin/sulbactam (P = 0.0001). Our results suggest that the clavulanic acid only shows an inhibitory effect on C. jejuni when combined with ticarcillin and that the inhibitors action is lower if the blaOXA-61 gene is highly expressed.

Adhesion and invasion of Campylobacter jejuni in chickens with a modified gut microbiota due to antibiotic treatment

Campylobacter jejuni (C. jejuni) is a predominant cause of foodborne illness in humans, while its colonization in chickens is usually asymptomatic. Antibiotics are not routinely used to treat chickens against C. jejuni, but in the face of other bacterial diseases, C. jejuni may be exposed to antibiotics. In this study, chickens were treated with antibiotics (AT) to modify the gut microbiota composition and compared with untreated chickens (Conv) with respect to changes in C. jejuni-colonization and bacterial-intestine interaction. Groups of AT and Conv chickens were inoculated after an antibiotic-withdrawal time of eight days with one of three different C. jejuni isolates to identify possible strain variations. Significantly higher numbers of colony forming units of C. jejuni were detected in the cecal content of AT birds, with higher colonization rates in the spleen and liver compared to Conv birds independent of the inoculated strain (p < 0.05). Clinical signs and histopathological lesions were only observed in C. jejuni-inoculated AT birds. For the first time we demonstrated C. jejuni invasion of the cecal mucosa in AT chickens and its inter- and intracellular localization by using antigen-straining, and electronic microscopy. This study provides the first circumstantial evidence that antibiotic treatment with lasting modification of the microbiota may provide a suitable environment for C. jejuni invasion also in chickens which may subsequently increase the risk of C. jejuni-introduction into the food chain.

Microbial metabolite deoxycholic acid shapes microbiota against Campylobacter jejuni chicken colonization.

Despite reducing the prevalent foodborne pathogen Campylobacter jejuni in chickens decreases campylobacteriosis, few effective approaches are available. The aim of this study was to use microbial metabolic product bile acids to reduce C. jejuni chicken colonization. Broiler chicks were fed with deoxycholic acid (DCA), lithocholic acid (LCA), or ursodeoxycholic acid (UDCA). The birds were also transplanted with DCA modulated anaerobes (DCA-Anaero) or aerobes (DCA-Aero). The birds were infected with human clinical isolate C. jejuni 81–176 or chicken isolate C. jejuni AR101. Notably, C. jejuni 81–176 was readily colonized intestinal tract at d16 and reached an almost plateau at d21. Remarkably, DCA excluded C. jejuni cecal colonization below the limit of detection at 16 and 28 days of age. Neither chicken ages of infection nor LCA or UDCA altered C. jejuni AR101 chicken colonization level, while DCA reduced 91% of the bacterium in chickens at d28. Notably, DCA diet reduced phylum Firmicutes but increased Bacteroidetes compared to infected control birds. Importantly, DCA-Anaero attenuated 93% of C. jejuni colonization at d28 compared to control infected birds. In conclusion, DCA shapes microbiota composition against C. jejuni colonization in chickens, suggesting a bidirectional interaction between microbiota and microbial metabolites.

Electrospun thyme essential oil/gelatin nanofibers for active packaging against Campylobacter jejuni in chicken

Campylobacter jejuni (C. jejuni) contamination on poultry surface posed great threats to meat industry and human health. In order to control the propagation of C. jejuni, the gelatin nanofibers containing thyme essential oil/β-cyclodextrin ε-polylysine nanoparticles (TCPNs) were engineered. Firstly, TCPNs were successfully fabricated via ionic gelation. The prepared TCPNs showed excellent antimicrobial activity against C. jejuni, which caused membranolysis and protein leakage of C. jejuni. Subsequently, TCPNs were incorporated into gelatin nanofibrous matrix via electrospinning to produce antimicrobial nanofibers. Uniformly disordered fibrous structure with good continuity and fine diameter distribution was observed. Finally, the aerobic bacterial count, thiobarbituric acid, total volatile basic nitrogen, pH, color and texture of meat samples packaged with the nanofibers were detected. The results implied the TCPNs embedded gelatin nanofibers had a promising prospect in meat preservation without impact on sensory evaluation.

Designing group dose-response studies in the presence of transmission

Dose-response studies are used throughout pharmacology, toxicology and in clinical research to determine safe, effective, or hazardous doses of a substance. When involving animals, the subjects are often housed in groups; this is in fact mandatory in many countries for social animals, on ethical grounds. An issue that may consequently arise is that of unregulated between-subject dosing (transmission), where a subject may transmit the substance to another subject. Transmission will obviously impact the assessment of the dose-response relationship, and will lead to biases if not properly modelled. Here we present a method for determining the optimal design – pertaining to the size of groups, the doses, and the killing times – for such group dose-response experiments, in a Bayesian framework. Our results are of importance to minimising the number of animals required in order to accurately determine dose-response relationships. Furthermore, we additionally consider scenarios in which the estimation of the amount of transmission is also of interest. A particular motivating example is that of Campylobacter jejuni in chickens. Code is provided so that practitioners may determine the optimal design for their own studies.

Oral administration of PLGA-encapsulated CpG ODN and Campylobacter jejuni lysate reduces cecal colonization by Campylobacter jejuni in chickens

Campylobacter jejuni (C. jejuni) is a major cause of bacterial food-borne illness in humans. It is considered a commensal organism of the chicken gut and infected chickens serve as a reservoir and shed bacteria throughout their lifespan. Contaminated poultry products are considered the major source of infection in humans. Therefore, to reduce the risk of human campylobacteriosis, it is essential to reduce the bacterial load in poultry products. The present study aimed to evaluate the protective effects of soluble and PLGA-encapsulated oligodeoxynucleotides (ODN) containing unmethylated CpG motifs (E-CpG ODN) as well as C. jejuni lysate as a multi-antigen vaccine against colonization with C. jejuni. The results revealed that oral administration of a low (5 µg) or high (50 µg) dose of CpG resulted in a significant reduction in cecal C. jejuni colonization by 1.23 and 1.32 log10 (P < .05) in layer chickens, respectively, whereas E-CpG significantly reduced cecal C. jejuni colonization by 1.89 and 1.46 log10 in layer and broiler chickens at day 22 post-infection (slaughter age in broilers), respectively. Similar patterns were observed for C. jejuni lysate; oral administration of C. jejuni lysate reduced the intestinal burden of C. jejuni in layer and broiler chickens by 2.24 and 2.14 log10 at day 22 post-infection, respectively. Moreover, the combination of E-CpG and C. jejuni lysate reduced bacterial counts in cecal contents by 2.42 log10 at day 22 post-infection in broiler chickens. Anti-C. jejuni IgG antibody (Ab) titers were significantly higher for broiler chickens receiving a low or high dose of E-CpG or a low dose of C. jejuni lysate than for chickens receiving the placebo. Furthermore, a positive correlation was observed between serum IgG Ab titers and cecal counts of C. jejuni in these groups. These findings suggest that PLGA-encapsulated CpG or C. jejuni lysate could be a promising strategy for control of C. jejuni in chickens.

Gene expression profiling of chicken cecal tonsils and ileum following oral exposure to soluble and PLGA-encapsulated CpG ODN, and lysate of Campylobacter jejuni

Campylobacter jejuni (C. jejuni) is a leading bacterial cause of food-borne illness in humans. Contaminated chicken meat is an important source of infection for humans. Chickens are not clinically affected by colonization, and immune responses following natural infection have limited effects on bacterial load in the gut. Induction of intestinal immune responses may possibly lead to a breakdown of the commensal relationship of chickens with Campylobacter. We have recently shown that soluble and poly D, L-lactic-co-glycolic acid (PLGA)-encapsulated CpG oligodeoxynucleotide (ODN) as well as C. jejuni lysate, are effective in reducing the intestinal burden of C. jejuni in chickens; however, the mechanisms behind this protection have yet to be determined. The present study was undertaken to investigate the mechanisms of host responses conferred by these treatments. Chickens were treated orally with soluble CpG ODN, or PLGA-encapsulated CpG ODN, or C. jejuni lysate, and expression of cytokines and antimicrobial peptides was evaluated in cecal tonsils and ileum using quantitative RT-PCR. Oral administration of soluble CpG ODN upregulated the expression of interferon (IFN)-γ, interleukin (IL)-1β, CXCLi2, transforming growth factor (TGF)-β4/1, IL-10 and IL-13, while treatment with PLGA-encapsulated CpG ODN upregulated the expression of IL-1β, CXCLi2, TGF-β4/1, IL-13, avian β-defensin (AvBD) 1, AvBD2 and cathelicidin 3 (CATHL-3). C. jejuni lysate upregulated the expression of IFN-γ, IL-1β, TGF-β4/1, IL-13, AvBD1, and CATHL-3. In conclusion, induction of cytokine and antimicrobial peptides expression in intestinal microenvironments may provide a means of reducing C. jejuni colonization in broiler chickens, a key step in reducing the incidence of campylobacteriosis in humans.