Campylobacter jejuni is one of the major causes of bacterial gastrointestinal disease in humans worldwide. This foodborne pathogen colonizes the intestinal tracts of chickens, and consumption of chicken and poultry products is identified as a common route of transmission. We analyzed two C. jejuni strains after oral challenge with 105 CFU/ml of C. jejuni per chick; one strain was a robust colonizer (A74/C) and the other a poor colonizer (A74/O). We also found extensive phenotypic differences in growth rate, biofilm production, and in vitro adherence, invasion, intracellular survival, and transcytosis. Strains A74/C and A74/O were genotypically similar with respect to their whole genome alignment, core genome, and ribosomal MLST, MLST, flaA, porA, and PFGE typing. The global proteomes of the two congenic strains were quantitatively analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and 618 and 453 proteins were identified from A74/C and A74/O isolates, respectively. Cluster of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that carbon metabolism and motility proteins were distinctively overexpressed in strain A74/C. The robust colonizer also exhibited a unique proteome profile characterized by significantly increased expression of proteins linked to adhesion, invasion, chemotaxis, energy, protein synthesis, heat shock proteins, iron regulation, two-component regulatory systems, and multidrug efflux pump. Our study underlines phenotypic, genotypic, and proteomic variations of the poor and robust colonizing C. jejuni strains, suggesting that several factors may contribute to mediating the different colonization potentials of the isogenic isolates.

The classic immunoblot technique is an important tool for identification and characterization of target proteins. However, a standard protocol for this classic immunoblot assay involves many steps that may cause experimental variations in each step and make quantification of antibodies in sera difficult. A capillary electrophoresis-based immunoblot system was developed to reduce potential problems in variations during the experimental process, enable protein identification in an automatic manner and quantitate various isotypes of antibodies in sera. In the present study, we used this system to examine the purity of the recombinant proteins and measure amounts of various isotypes of immunoglobins in chicken sera after immunization with two recombinant Salmonella FliD and FimA proteins. A single band of each protein was detected in the gel like images by this system after purification by nickel-chelated affinity chromatography. A good linear range of the protein concentrations was also obtained for each recombinant protein. This automated capillary immunoblot system was successfully used for detection and quantification of various immunoglobin isotypes against two recombinant Salmonella proteins from the immunized chicken sera, but not the un-immunized chicken sera. The chicken immunoglobin G (IgG) antibody response to the FliD protein from the immunized group was 1110- and 51,400-fold higher than that from the un-immunized chickens both two- and three-weeks post-vaccination, respectively. It was also observed that IgM antibody against the FliD protein from the immunized chickens was 1030-fold higher than that from the un-immunized chickens two weeks post-vaccination, but the IgM response declined to 120-fold between two groups from two weeks to three weeks after immunization. The IgM antibody response to the FimA protein from the immunized group was 1.84- and 1.12-fold higher than that from the un-immunized group, respectively, both two- and three-weeks post-vaccination, while the IgG antibody response from the immunized group was 8.07- and 27.6-fold higher than that from the un-immunized group, respectively, during the same period. These results suggest that this capillary-based immunoblot assay can be an alternative method for analyses and quantitation of chicken humoral immune response before and after immunization with any antigens and/or for investigation in Salmonella outbreaks.

Antimicrobial resistance (AR) spread is a worldwide health challenge, stemming in large part, from the ability of microbes to share their genetic material through horizontal gene transfer (HGT). Overuse and misuse of antibiotics in clinical settings and in food production have been linked to this increased prevalence and spread of AR. Consequently, public health and consumer concerns have resulted in a remarkable recent reduction in antibiotics used for food animal production. This is driven by the assumption that removing this selective pressure will favor the recovery of antibiotic susceptible taxa and will limit AR sharing through HGT, allowing the currently available antibiotic arsenal to be effective for a longer period. In this study we used broiler chicks raised antibiotic-free and Salmonella enterica serovar Heidelberg (SH), as a model food pathogen, to test this hypothesis. Our results show that neonatal broiler chicks challenged with an antibiotic susceptible SH strain and raised without antibiotics carried susceptible and multidrug resistance SH strains 14 days after challenge. SH infection perturbed the microbiota of broiler chicks and gavaged chicks acquired antibiotic resistant SH at a higher rate. We determined that the acquisition of a plasmid from commensal Escherichia coli population conferred multidrug resistance phenotype to SH recipients and carriage of this plasmid increased the fitness of SH under acidic selection pressure. These results suggest that HGT of AR shaped the evolution of SH and that antibiotic use reduction alone is insufficient to limit antibiotic resistance transfer from commensal bacteria to Salmonella . Importance The reported increase in antibiotic resistant bacteria in humans have resulted in a major shift away from antibiotics use in food animal production. This has been driven by the assumption that removing antibiotics will select for antibiotic susceptible bacterial taxa, and this in turn will allow the currently available antibiotic arsenal to be more effective. This shift in practice has highlighted new questions that need to be answered to assess the effectiveness of antibiotic removal in reducing the spread of antibiotic resistance bacteria. This research demonstrates that antibiotic susceptible Salmonella Heidelberg strains can acquire multidrug resistance from commensal bacteria present in the gut of neonatal broiler chicks, even in the absence of antibiotic selection. We demonstrate that exposure to acidic pH drove the horizontal transfer of antimicrobial resistance plasmids and suggests that simply removing antibiotics from food-animal production might not be sufficient to limit the spread of antimicrobial resistance.

The overuse and misuse of antibiotics in clinical settings and in food production have been linked to the increased prevalence and spread of antimicro-bial resistance (AR). Consequently, public health and consumer concerns have resulted in a remarkable reduction in antibiotics used for food animal production. However, there are no data on the effectiveness of antibiotic removal in reducing AR shared through horizontal gene transfer (HGT). In this study, we used neonatal broiler chicks and Salmonella enterica serovar Heidelberg, a model food pathogen, to test if chicks raised antibiotic free harbor transferable AR. We challenged chicks with an antibiotic-susceptible S. Heidelberg strain using various routes of inoculation and determined if S. Heidelberg isolates recovered carried plasmids conferring AR. We used antimicrobial susceptibility testing and whole-genome sequencing (WGS) to show that chicks grown without antibiotics harbored an antimicrobial resistant S. Heidelberg population at 14 days after challenge and chicks challenged orally acquired AR at a higher rate than chicks inoculated via the cloaca. Using 16S rRNA gene sequencing, we found that S. Heidelberg infection perturbed the microbiota of broiler chicks, and we used metagenomics and WGS to confirm that a commensal Escherichia coli population was the main reservoir of an IncI1 plasmid acquired by S. Heidelberg. The carriage of this IncI1 plasmid posed no fitness cost to S. Heidelberg but increased its fitness when exposed to acidic pH in vitro. These results suggest that HGT of plasmids carrying AR shaped the evolution of S. Heidelberg and that an-tibiotic use reduction alone is insufficient to limit antibiotic resistance transfer from commensal bacteria to Salmonella enterica. IMPORTANCE The reported increase in antibiotic-resistant bacteria in humans has resulted in a major shift away from antibiotic use in food animal production. This shift has been driven by the assumption that removing antibiotics will select for anti-biotic susceptible bacterial taxa, which in turn will allow the currently available anti-biotic arsenal to be more effective. This change in practice has highlighted new questions that need to be answered to assess the effectiveness of antibiotic removal in reducing the spread of antibiotic resistance bacteria. This research demonstrates that antibiotic-susceptible Salmonella enterica serovar Heidelberg strains can acquire multidrug resistance from commensal bacteria present in the gut of neonatal broiler chicks, even in the absence of antibiotic selection. We demonstrate that exposure to acidic pH drove the horizontal transfer of antimicrobial resistance plasmids and suggest that simply removing antibiotics from food animal production might not be sufficient to limit the spread of antimicrobial resistance.

Here, we report the draft genome sequences of robust (A74/C_24-3) and poor (A74/O_2-2) chicken-colonizing Campylobacter jejuni isolates. Whole-genome sequence analyses of these isolates will be helpful in facilitating further studies to identify genetic factors used in chicken colonization.

Many laboratories sampling foods for Salmonella are interested only in presence or absence of Salmonella, so only one colony may be selected. The objectives of this study were to use two selective enrichment broths and two selective agar plating media for Salmonella recovery from naturally contaminated broiler carcass rinsates and evaluate these media combinations on Salmonella serotypes recovered from each carcass. Broiler carcasses (n = 52) from a commercial processing plant prior to chilling were rinsed with buffered peptone water and after incubation subcultured to gram-negative and tetrathionate, and after inoculation to Rappaport Vassiliadis broth which was incubated and then streaked onto plates of Brilliant Green Sulfa and Xylose-Lysine-Tergitol-4 agar. On 11/49 positive carcasses, both plating media yielded the same serotypes; for the other 38 positive samples different serotypes were found on the different plating media. Enrichment and plating media combinations influence the serotypes recovered and demonstrates bias even in a limited study such as this.

Although the gastrointestinal pathogen Campylobacter jejuni was considered asaccharolytic, >50% of sequenced isolates possess an operon for l -fucose utilization. In C. jejuni NCTC11168, this pathway confers l -fucose chemotaxis and competitive colonization advantages in the piglet diarrhea model, but the catabolic steps remain unknown. Here we solved the putative dehydrogenase structure, resembling FabG of Burkholderia multivorans . The C. jejuni enzyme, FucX, reduces l -fucose and d -arabinose in vitro and both sugars are catabolized by fuc -operon encoded enzymes. This enzyme alone confers chemotaxis to both sugars in a non-carbohydrate-utilizing C. jejuni strain. Although C. jejuni lacks fucosidases, the organism exhibits enhanced growth in vitro when co-cultured with Bacteroides vulgatus, suggesting scavenging may occur. Yet, when excess amino acids are available, C. jejuni prefers them to carbohydrates, indicating a metabolic hierarchy exists. Overall this study increases understanding of nutrient metabolism by this pathogen, and identifies interactions with other gut microbes.

Contaminated poultry meat is a major source of human foodborne illnesses. Many interventions have been developed to reduce and/or eliminate human foodborne pathogens in poultry products; however, treatments with cold plasma or carnosine or their combination have not been extensively investigated. In this study, the bacterial microflora of poultry meat samples after treatments with cold plasma and carnosine were characterized with EcoPlates in the OmniLog system. The plates were incubated at 25 degrees C for 7 days in the OmniLog chamber, and bacterial growth was monitored by recording formazan production every 30 min at an optical density of 590 nm. The kinetics of lag, log, and stationary phases of bacterial growth followed the Gompertz sigmoidal model but with different inflection times and asymptotes at the log phase and the stationary phase, respectively. Results indicated that treatment of poultry meat samples with cold plasma technology and carnosine could inhibit growth of the bacteria in the treated meat samples. Of 31 chemicals tested, phenylethylamine, alpha-D-lactose, D,L-alpha-glycerol phosphate, 2-hydroxybenzoic acid, gamma-hydroxybutyric acid, alpha-ketobutyric acid, and D-malic acid could not be metabolized by bacteria in the meat samples. Future research is required to determine whether these seven chemicals that inhibited growth of bacteria in these meat samples can be used as food preservatives for extending the shelf life of these products. Whether the bacterial flora can be an indicator of effectiveness for meat samples treated with cold plasma, carnosine, or both needs further study. HIGHLIGHTS Bacteria in broiler meat were assessed with EcoPlates for utilization of single carbon sources. The kinetics of bacterial growth followed the Gompertz sigmoidal model. Cold plasma technology and carnosine could inhibit bacterial growth in meat samples. Seven chemicals in meat samples could not be used by bacteria as a carbon source.

Response surface methodology (RSM) was used to optimize in-package cold plasma (IPCP) treatment for raw chicken breast meat. Non-inoculated and inoculated samples with Campylobacter (5.06 log(10) CFU/mL) and Salmonella (5.40 log(10) CFU/mL) were packaged in 35% O-2/60% CO2, 65% O-2/30% CO2, or 95% O-2/0% CO2 and treated at 60, 70, or 80 kV for 60, 180, or 300 s. Microbial counts, color, pH, and drip loss were measured. There were no differences in Campylobacter, Salmonella, drip loss, or pH between treatments. IPCP could reduce psychrophiles by > 1.0 log, depending on O-2 and voltage interaction. Treatment effects on meat color varied by CIE L*a*b*. RSM analysis suggested that packaging atmosphere with 35% O-2 and 60% CO2 and IPCP at 60 kV for 60 s were the optimal condition for maximizing microbiological shelf-life and minimizing appearance changes in raw chicken meat packaged in a barrier film and stored at 4 degrees C for 5 days. Industrial relevance: The current study used response surface methodology to determine the optimal condition in the combination of voltage and time of an in-package cold plasma (IPCP) treatment and modified atmosphere (MA) packaging for extending shelf life and reducing food safety risk of pre-packaged raw chicken breast meat during refrigerated storage. Our data provided evidence that the optimal IPCP-treatment parameters and packaging atmosphere varied with targeted microorganisms and CIEL*a*b* color indicators. In MA packaging, changes in IPCP treatment voltage and time did not affect populations of Campylobacter and Salmonella, drip loss and pH; however, low IPCP treatment voltage (60 kV) for short exposure time (60 s) was as effective as the high voltage (80 kV) for longer treatment time (300 s) against psychrophiles and could reduce the changes in raw meat appearance (indicated with CIEL* measurements) due to IPCP treatment. Reducing O-2 in packages from 95 to 35% resulted in better inhibition of psychrophilic growth on raw meat and changes in raw meat appearance or meat color lightness. It is recommended to use MA of 35% O-2 and 60% CO2 and IPCP treatment at 60 kV for 60 s to extend microbiological shelf life, improve food safety, and retain quality of raw chicken breast meat packaged with a barrier film and stored at refrigerated temperature.

To provide safer food, many technologies have been used to preserve food. One such technology is cold plasma, which can reduce viable bacterial counts in various food matrices. However, bacterial communities in food matrices before and after cold plasma treatment have not been investigated. In this communication, the EcoPlates™ were used to physiologically profile bacterial communities from poultry ground meat treated with rosemary, cold plasma or both. The cultures in the plates were incubated at 25 °C for seven days in an OmniLog® system. Responses of the bacterial communities to 31 chemicals were measured on formazan production. The results show that the three parameters of the Gompertz growth curves were observed in all samples, 2-hydroxybenzoic acid could not be used, while pyruvic acid methyl ester was used for a carbon source by the bacterial communities from all meat samples, each bacterial community metabolized different numbers of chemical compounds at different rates, and reduction of bacterial functional diversity was observed in the poultry meat samples treated with cold plasma and rosemary. In the future, investigations on whether the physiological profiling in bacterial communities be used as an indicator for effectiveness of cold plasma treatment of meat samples.

Detection of Salmonella on commercially processed broiler carcasses is essential to reduce the incidences of human salmonellosis. This study was designed to compare the standard procedure for Salmonella detection with two commercial screening methods. During seven separate visits to two processing plants, eight carcasses were obtained (n = 112). Each carcass was rinsed and the rinsate processed according to the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS) protocol. Predetermined aliquots of rinsates were screened on the BAX (R) and Roka (R) instruments according to manufacturer's protocol and analyzed using the USDA, FSIS cultural method. Four Salmonella-like colonies from presumptive positive rinsates were selected, screened biochemically, and serologically confirmed as Salmonella. Results indicated Salmonella was recovered from 15.2% (17/112), 14.3% (16/112), and 12.5% (14/112) of carcasses by cultural methods, BAX, and Roka analysis, respectively. These findings indicate that both rapid, molecular methods tested were as effective as the conventional cultural procedure in detecting Salmonella from broiler carcass rinsates. Practical Applications According to the results of this study, there was no statistical difference in the number of carcass rinsates in which Salmonella was detected by the three methods. The ability of all three methods to detect naturally occurring Salmonella provides the poultry industry and regulatory agencies more tools to increase the safety of poultry products available to the consumer.

Poultry production is a major agricultural output worldwide. It is known that the gut health of broilers is essential for their growth and for providing wholesome products for human consumption. Previously, the microbial diversity of broiler ceca was studied at the genetic level. However, the functional diversity and metabolic activity of broiler cecal bacterial communities are not fully investigated. Recently, the EcoPlates™ from Biolog, Inc. have been used for characterizing bacterial communities from various environments. In this study, we applied these plates to physiologically profile cecal bacterial communities in broilers. The ceca were aseptically excised from 6-week-old broilers, and their contents were suspended in phosphate buffered saline. The cultures in the EcoPlates™ were incubated at 42 °C for 5 days in an OmniLog® system. Responses of the bacterial communities to the various chemicals as carbon sources were measured on formazan production. The results show sigmoidal growth curves with three phases in all 12 cecal samples. Cecal bacterial communities could not use 11 carbon substrates for carbon sources; instead, they used pyruvic acid methyl ester, glycogen, glucose-1-phosphate and N-acetyl-D-glucosamine most frequently. Each bacterial community metabolized various numbers of the substrates at different rates among broilers. In the future, modification of the culture conditions to mimic the gut environment is needed. More investigations on the effects of nutrients, Salmonella or Campylobacter on physiological functions of cecal bacterial communities will provide insights into the improvement of animal well-being, saving production expenditures for producers and providing safer poultry products for human consumption.

Proteus mirabilis, a Gram-negative bacterium, is ubiquitous in the environment and is considered as the normal microflora in the human gastrointestinal tract. However, this bacterium is an opportunistic pathogen in humans, often causing urinary tract infections. Moreover, Proteus has been frequently isolated from food animals, including poultry. Whether this bacterium contributes to the foodborne illness in humans is unclear. In this report, P. mirabilis isolates recovered from broilers during housing in the units were characterized, their antimicrobial activity was assayed, and broiler immune response to the soluble proteins was determined. Cecal contents and fecal droppings were treated according to the standard protocol for isolation. Speciation based on biochemical reactions and the antimicrobial activity of the isolates were carried out using commercial kits. Immunoblot was assayed to determine immune status of broilers against P. mirabilis. A total of 10 isolates of P. mirabilis were selected for further characterization. These isolates could grow in pH 6.0 and 1% NaCl conditions. They were resistant to sodium lactate, troleandomycin, rifamycin SV, vancomycin, but sensitive to nalidixic acid, cefotaxime and novobiocin. Moreover, the CTX, ACC, CMY-1, BIC, NDM, VEB, qnrB and qnrD genes were detected by PCR amplification in all isolates. Sera from broilers harboring this bacterium reacted to the P. mirabilis soluble proteins, but not from litter- and age-matched P. mirabilis negative and SPF chickens, indicating that this bacterium infected chickens that could have humoral immune response against P. mirabilis. This study provides a rationale for further monitoring P. mirabilis during poultry production to determine whether this bacterium poses potential threats to public health.

Campylobacter jejuni, a Gram-negative rod, is a zoonotic pathogen associated with human acute bacterial gastroenteritis worldwide. The flagellum, composed of more than 35 proteins, is responsible for colonization of C. jejuni in the host gastrointestinal tract as well as inducing protective antibodies against the homologous serotype. In our previous study, we demonstrated that the flagellar capping protein (FliD) is an immunodominant protein that reacted strongly to sera from field chickens. In this communication, we mapped linear immunoreactive epitopes on FliD using a set of 158 synthetic peptides of 15-mer overlapping with 11 amino acid residues on peptide microarrays with sera from field chickens. The results from peptide microarrays showed (1) no cross-reactivity of the immobilized peptides with the secondary anti-chicken antibody in the control incubation, and (2) heterogeneous patterns of sera reacting to the immobilized peptides. The peptides that reacted to more than three chicken sera and had higher averages of fluorescence units were selected for further validation by the peptide ELISA. The results showed peptides 24, 91 and 92 had relatively high reactivity and less variation among 64 individual serum samples, indicating these peptides represented the shared immunodominant epitopes on the C. jejuni FliD protein. These peptides were also recognized by sera from chickens immunized with the purified recombinant FliD protein. The findings of the specific shared linear immunodominant epitopes on FliD in this study provide a rationale for further evaluation to determine their utility as epitope vaccines covering multiple serotypes for chicken immunization, and subsequently, for providing safer poultry products for human consumption.

Campylobacter jejuni is a Gram-negative spiral rod bacterium and is the leading but underreported bacterial food-borne pathogen that causes human campylobacteriosis worldwide. Raw or undercooked poultry products are regarded as a major source for human infection. C. jejuni flagella have been implicated in colonization and adhesion to the mucosal surface of chicken gastrointestinal tracts. Therefore, flagellar proteins would be the excellent targets for further investigation. In this report, we used the recombinant technology to generate a battery of C. jejuni flagellar proteins, which were purified by His tag affinity chromatography and determined antigenic profiles of these recombinant flagellar proteins using sera from chickens older than 6 weeks of age. The immunoblot results demonstrate that each chicken serum reacted to various numbers of recombinant flagellar proteins. Among these recombinant proteins, chicken sera reacted predominantly to the FlgE1, FlgK, FlhF, FliG and FliY proteins. These antibody screening results provide a rationale for further evaluation of these recombinant flagellar proteins as potential vaccines for chickens to improve food safety as well as investigation of host immune response to C. jejuni .

Campylobacter is a natural member of the gut microflora in many commercial broilers and as such can become a contaminant on edible surfaces during processing. Culturing gut contents or feces can be a means to determine flock status prior to live-haul. The wide variety of non-Campylobacter background bacteria in these complex samples contaminates growth media and can make it very difficult to isolateCampylobacter. Over the course of 17 months, we cultured cecal contents from 100 different broiler flocks. For the last 50 flocks, we tested 3 selective plating media with and without the additional selection of a 0.45-μm filter for detection ofCampylobacter from cecal contents. Furthermore, from the last 50 flocks we also collected and cultured carcass rinse samples. Growth media tested included: Campy–Cefex Agar, Campy–Line Agar, and RF-Campylobacter jejuni/coli agar. About half (52%) of the 100 tested flocks were positive forCampylobacter; positive flocks were detected during each month of the year. Overall, theCampylobacter status of cecal contents from one carcass was predictive of the status of a carcass rinse from the same flock. Placing a complex sample such as cecal contents onto a 0.45-μm filter laid on top of the plating medium improved the detection ofCampylobacter by eliminating non-Campylobacter background colonies. All media allowed for detection ofCampylobacter from less complex carcass rinse samples without filtering. However, Campy–Cefex agar had higher numbers of competing bacterial colonies than did Campy–Line agar or RF-Campylobacter jejuni/coli agar.

Campylobacter jejuni , a flagellated, spiral-rod, Gram-negative bacterium, is the leading pathogen of human acute bacterial gastroenteritis worldwide, and chickens are regarded as a major reservoir of this micro-organism. Bacterial flagella, composed of more than 35 proteins, play important roles in colonization and adhesion to the mucosal surface of chicken caeca. In this study, the flagellar capping protein, FliD, encoded by the fliD gene, from the Campylobacter jenuni D1-39 isolate was expressed and characterized, and its antigenicity determined. The fliD gene comprised 1929 nt, potentially encoding a 642 aa peptide with a calculated molecular mass of 69.6 kDa. This gene was PCR amplified and overexpressed in Escherichia coli . The recombinant FliD protein was purified by cobalt-chelating affinity chromatography and confirmed by nucleotide sequencing of the expression plasmid, SDS-PAGE analysis, His tag detection and matrix-assisted laser desorption/ionization time of flight mass spectrometry. The immunoblot data showed that the purified recombinant FliD protein reacted strongly to sera from broiler chickens older than 4 weeks, indicating that anti-FliD antibody may be prevalent in the poultry population. These results provide a rationale for further evaluation of the FliD protein as a vaccine candidate for broiler chickens to improve food safety for poultry.

Campylobacter jejuni, a Gram-negative rod bacterium, is the leading causative agent of human acute bacterial gastroenteritis worldwide. Consumption and handling of raw or undercooked poultry are regarded as a major source for human infection. Because bacterial chemotaxis guides microorganisms to colonization and invasion in the host cells, proteins involved in chemotactic processes can be novel targets for vaccine development. In this communication, we report amplification, cloning and expression of the C. jejuni chemotactic proteins in an Escherichia coli expression system. A total of 15 chemotactic protein genes were successfully expressed. These recombinant proteins were confirmed by nucleotide sequencing, SDS-PAGE analysis and immunoblot analysis of six-His and hemagglutinin tags. Twelve recombinant chemotactic proteins were further tested whether they were antigenic using sera from broiler chickens older than 4 weeks. The immunoblot results show that each chicken serum reacted to a variety of the recombinant proteins, but all sera reacted to the Cjj0473 gene product (annotated as a methyl-accepting chemotaxis protein), suggesting that anti-Campylobacter antibodies may be prevalent in the poultry population. These antibody screening results provide a rationale for further evaluation of the Cjj0473 protein as a potential vaccine for broilers to improve human food safety.