Identification of a New Source of Campylobacter Contamination in Poultry: Transmission from Breeder Hens to Broiler Chickens

A systematic review and meta-analysis of the sources of Campylobacter in poultry production (preharvest) and their relative contributions to the microbial risk of poultry meat

A systematic review and meta-analysis were conducted to idetnify the relative contributions of the sources of Campylobacter in poultry live production to Campylobacter prevalence of broiler meat. The keywords of Campylobacter, prevalence, live production, and broiler were used in Google Scholar to address the research interest. A total of 16,800 citations were identified, and 63 relevant citations were included in the meta-analysis after applying predetermined inclusion and exclusion criteria. A generalized linear mixed model approach combined with logit transformation was used in the current meta-analysis to stabilize the variance. The analysis revealed that Campylobacter is ubiquitous in the poultry house exterior environment including surroundings, wildlife, domestic animals, and farm vehicle, with a predicted prevalence of 14%. The recovery of Campylobacter in the interior environment of the poultry house is far less abundant than in the exterior, with a prevalence of 2%, including litter, water, insects, mice, feed, and air. A lack of evidence was observed for vertical transmission due to the day-old chicks being free of Campylobacter from 4 studies identified. Live birds are the predominant carrier of Campylobacter, with a predicted prevalence of 41%. Transportation equipment used for live haul had an overall prevalence of 39%, with vehicles showing a predicted prevalence of 44% and crates with a predicted prevalence of 22%. The results of this meta-analysis highlight the need to implement effective biosecurity measures to minimize the risk of Campylobacter in poultry meat, as human activity appears to be the primary factor for Campylobacter introduction.

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.

Current Perspectives and Potential of Probiotics to Limit Foodborne Campylobacter in Poultry

Poultry has been one of the major contributors of Campylobacter related human foodborne illness. Numerous interventions have been applied to limit Campylobacter colonization in poultry at the farm level, but other strategies are under investigation to achieve more efficient control. Probiotics are viable microbial cultures that can establish in the gastrointestinal tract (GIT) of the host animal and elicit health and nutrition benefits. In addition, the early establishment of probiotics in the GIT can serve as a barrier to foodborne pathogen colonization. Thus, probiotics are a potential feed additive for reducing and eliminating the colonization of Campylobacter in the GIT of poultry. Screening probiotic candidates is laborious and time-consuming, requiring several tests and validations both in vitro and in vivo. The selected probiotic candidate should possess the desired physiological characteristics and anti-Campylobacter effects. Probiotics that limit Campylobacter colonization in the GIT rely on different mechanistic strategies such as competitive exclusion, antagonism, and immunomodulation. Although numerous research efforts have been made, the application of Campylobacter limiting probiotics used in poultry remains somewhat elusive. This review summarizes current research progress on identifying and developing probiotics against Campylobacter and presenting possible directions for future research efforts.

Investigation of Campylobacter colonization in three Australian commercial free-range broiler farms

Campylobacter spp. contaminated poultry products are strongly associated with foodborne illnesses worldwide. Development of effective management strategies to reduce contamination by Campylobacter spp. requires an improved understanding of the numerous factors that drive these contamination processes. Currently, chicken farms are using more free-range chicken meat production systems in response to consumer preferences. However, Campylobacter spp. colonization has rarely been investigated on free-range broiler farms. The present study investigated the temporal and environmental factors influencing Campylobacter spp. colonization of free-range broilers as well as potential sources and genetic diversity of Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) in commercial free-range broiler farms. Genetic linkages among the isolates were analyzed using flaA amplicon analysis. Campylobacter coli was first detected in fecal samples of a commercial free-range broiler flock on day 10 of rearing. Multiple genotypes of C. jejuni and C. coli were identified in this study. The farm environment was identified as a potential source of C. jejuni and C. coli colonization of free-range broilers. The dominant Campylobacter genotype varied between free-range broiler farms over time, with C. jejuni being the most frequently isolated species. These findings enhance the understanding of C. jejuni and C. coli colonization in free-range broiler farms and could inform the development of more effective intervention strategies to help control this important foodborne pathogen.

Semi-Quantification of Total Campylobacter and Salmonella During Egg Incubations Using a Combination of 16S rDNA and Specific Pathogen Primers for qPCR

Rapid molecular techniques that evaluate eggs for the presence of foodborne pathogens is an essential component to poultry food safety monitoring. Interestingly, it is not just table eggs that contribute to outbreaks of foodborne disease. Broiler layer production actively contributes to sustaining of foodborne pathogens within a flock. The surface contamination of production eggs with invasive pathogens such as Salmonella enterica, Campylobacter jejuni, and Listeria monocytogenes during embryogenesis results in gastrointestinal tract (GIT) colonization. Pathogens that secure a niche within the GIT during embryonic development are nearly impossible to eradicate from the food chain. Therefore, current monitoring paradigms are not comprehensive because they fail to capture the presence of invasive pathogens within the embryonic GIT rapidly. By developing tools to recognize the pathogens' presence in the GIT during embryogenesis, producers are then able to spot evaluate broiler eggs for their potential risk as carriers of foodborne pathogens. In this study a novel qPCR assay was developed to semi-quantify pathogen load relative to total bacterial burden. Eggs sampled from three independent production broiler flocks of different ages were assayed for S. enterica (invA), C. jejuni (HipO), and L. monocytogenes (HlyA) against total microbial load (16s). The eggs were sampled at 1-day post-set within each flock, 2 weeks post-set, after vaccination (at 2.5 weeks) and 1-day post-hatch. The eggs were washed, and the yolk and embryonic chick GIT were collected. The DNA was extracted and subjected to a qPCR assay. The results confirm a novel technique for pathogen monitoring relative to total bacterial load and a unique method for monitoring the dynamics of foodborne pathogen invasion throughout broiler egg production.

Preharvest Food Safety in Broiler Chicken Production

Preharvest food safety in broiler production is a systematic approach to control the introduction, propagation, and dissemination of Salmonella and Campylobacter from breeder flocks to the end of their progeny (broilers) life cycle. New and revised more stringent performance standards for these pathogens at the processing plant level require continuous evaluation of the preharvest management practices and intervention strategies used by the poultry industry. The implementation of stricter biosecurity plans, vaccination of breeder flocks for Salmonella , and usage of feed that is free of animal by-products are some of the measures recommended to control the pathogens. Interventions shown to be effective in experimental settings need to be assessed for their cost-effectiveness and efficiency when applied at the farm level.

Campylobacter epidemiology from breeders to their progeny in Eastern Spain

While horizontal transmission is a route clearly linked to the spread of Campylobacter at the farm level, few studies support the transmission of Campylobacter spp. from breeder flocks to their offspring. Thus, the present study was carried out to investigate the possibility of vertical transmission. Breeders were monitored from the time of housing day-old chicks, then throughout the laying period (0 to 60 wk) and throughout their progeny (broiler fattening, 1 to 42 d) until slaughter. All samples were analyzed according with official method ISO 10272:2006. Results revealed that on breeder farms, Campylobacter isolation started from wk 16 and reached its peak at wk 26, with 57.0% and 93.2% of positive birds, respectively. After this point, the rate of positive birds decreased slightly to 86.0% at 60 wk. However, in broiler production all day-old chicks were found negative for Campylobacter spp, and the bacteria was first isolated at d 14 of age (5.0%), with a significant increase in detection during the fattening period with 62% of Campylobacter positive animals at the end of the production cycle. Moreover, non-positive sample was determined from environmental sources. These results could be explained because Campylobacter may be in a low concentration or in a non-culturable form, as there were several studies that successfully detected Campylobacter DNA, but failed to culture. This form can survive in the environment and infect successive flocks; consequently, further studies are needed to develop more modern, practical, cost-effective and suitable techniques for routine diagnosis.

Cecal bacterial communities in wild Japanese rock ptarmigans and captive Svalbard rock ptarmigans

Preservation of indigenous gastrointestinal microbiota is deemed to be critical for successful captive breeding of endangered wild animals, yet its biology is poorly understood. Here, we investigated cecal bacterial communities in wild Japanese rock ptarmigans (Lagopus muta japonica) and compared them with those in Svalbard rock ptarmigans (L. m. hyperborea) in captivity. Ultra-deep sequencing of 16S rRNA gene indicated that the community structure of cecal microbiota in wild rock ptarmigans was remarkably different from that in captive Svalbard rock ptarmigans. Fundamental differences between bacterial communities in the two groups of birds were detected at the phylum level. Firmicutes, Actinobacteria, Bacteroidetes and Synergistetes were the major phyla detected in wild Japanese rock ptarmigans, whereas Firmicutes alone occupied more than 80% of abundance in captive Svalbard rock ptarmigans. Furthermore, unclassified genera of Coriobacteriaceae, Synergistaceae, Bacteroidaceae, Actinomycetaceae, Veillonellaceae and Clostridiales were the major taxa detected in wild individuals, whereas in zoo-reared birds, major genera were Ruminococcus, Blautia, Faecalibacterium and Akkermansia. Zoo-reared birds seemed to lack almost all rock ptarmigan-specific bacteria in their intestine, which may explain the relatively high rate of pathogenic infections affecting them. We show evidence that preservation and reconstitution of indigenous cecal microflora are critical for successful ex situ conservation and future re-introduction plan for the Japanese rock ptarmigan.

Potential Transmission Pathways of Streptococcus gallolyticus subsp. gallolyticus

Streptococcus gallolyticus subsp. gallolyticus (S. gallolyticus subsp. gallolyticus), a member of group D streptococci, is an inhabitant of the animal and human gastrointestinal tract. Furthermore, it is a facultative pathogen which causes e.g. endocarditis, septicemia and mastitis. S. gallolyticus subsp. gallolyticus may be transmitted either directly or indirectly between animals and humans. However, the transmission routes are an unsolved issue. In this study, we present systematic analyses of an S. gallolyticus subsp. gallolyticus isolate of an infective endocarditis patient in relation to isolates of his laying hen flock. Isolates from pooled droppings of laying hens, pooled dust samples and human blood culture were characterized by using multilocus sequence typing (MLST) and DNA fingerprinting. MLST revealed the same allelic profile of isolates from the human blood culture and from the droppings of laying hens. In addition, these isolates showed clonal identity regarding a similar DNA fingerprinting pattern. For the first time, we received a hint that transmission of S. gallolyticus subsp. gallolyticus between poultry and humans may occur. This raises the question about the zoonotic potential of isolates from poultry and should be considered in future studies.

Thermotolerant Campylobacter during Broiler Rearing: Risk Factors and Intervention

Thermotolerant Campylobacters are one of the most important bacterial causative agents of human gastrointestinal illness worldwide. In most European Union (EU) member states human campylobacteriosis is mainly caused by infection with Campylobacter jejuni or Campylobacter coli following consumption or inadequate handling of Campylobacter-contaminated poultry meat. To date, no effective strategy to control Campylobacter colonization of broilers during rearing is available. In this review, we describe the public health problem posed by Campylobacter presence in broilers and list and critically review all currently known measures that have been researched to lower the numbers of Campylobacter bacteria in broilers during rearing. We also discuss the most promising measures and which measures should be investigated further. We end this review by elaborating on readily usable measures to lower Campylobacter introduction and Campylobacter numbers in a broiler flock.

A systematic review characterizing on-farm sources of Campylobacter spp. for broiler chickens

Campylobacter and antimicrobial-resistant Campylobacter are frequently isolated from broiler chickens worldwide. In Canada, campylobacteriosis is the third leading cause of enteric disease and the regional emergence of ciprofloxacin-resistant Campylobacter in broiler chickens has raised a public health concern. This study aimed to identify, critically appraise, and synthesize literature on sources of Campylobacter in broilers at the farm level using systematic review methodology. Literature searches were conducted in January 2012 and included electronic searches in four bibliographic databases. Relevant studies in French or English (n = 95) conducted worldwide in any year and all study designs were included. Risk of Bias and GRADE criteria endorsed by the Cochrane collaboration was used to assess the internal validity of the study and overall confidence in the meta-analysis. The categories for on-farm sources were: broiler breeders/vertical transfer (number of studies = 32), animals (n = 57), humans (n = 26), environment (n = 54), and water (n = 63). Only three studies examined the antimicrobial resistance profiles of Campylobacter from these on-farm sources. Subgroups of data by source and outcome were analyzed using random effect meta-analysis. The highest risk for contaminating a new flock appears to be a contaminated barn environment due to insufficient cleaning and disinfection, insufficient downtime, and the presence of an adjacent broiler flock. Effective biosecurity enhancements from physical barriers to restricting human movement on the farm are recommended for consideration to enhance local on-farm food safety programs. Improved sampling procedures and standardized laboratory testing are needed for comparability across studies. Knowledge gaps that should be addressed include farm-level drug use and antimicrobial resistance information, further evaluation of the potential for vertical transfer, and improved genotyping methods to strengthen our understanding of Campylobacter epidemiology in broilers at the farm-level. This systematic review emphasizes the importance of improved industry-level and on-farm risk management strategies to reduce pre-harvest Campylobacter in broilers.

Impact of 6 different intestinal bacteria on broiler breeder sperm motility in vitro

Male fertility is often evaluated by measuring sperm parameters, including concentration, viability, and motility. This is important because after copulation occurs, sperm must overcome many barriers in the female reproductive tract to fertilize the ovum. In mammalian species, sperm have been shown to have reduced motility when bacteria are present. In male broiler breeders, bacteria have been associated with spermatozoa, but their effect on motility has not been investigated. The sperm quality index is a modern rapid method of evaluating avian sperm motility. Therefore, the objective of this study was to use the sperm quality index to determine if broiler breeder sperm motility is reduced when semen is exposed to various bacteria. In this experiment, semen was collected from 20 broiler breeders to obtain a pooled neat semen sample. Six different intestinal bacteria, Salmonella enterica, Escherichia coli, Campylobacter jejuni, Clostridium bifermentans, Lactobacillus acidophilus, and Bifidobacterium animalis were cultured overnight. For each bacterium, 50 µL of semen was diluted in 450 µL of saline, sterile broth, or the overnight culture, creating 3 treatments. The experiment was repeated twice. In each treatment, 3 replicates were evaluated at 0 and 10 min postinoculation, creating a completely randomized design with a split plot over time. Also, the pH was measured for each treatment at 0 and 10 min. The results indicated that all broths containing bacteria immediately reduced broiler breeder sperm motility when compared with the controls (P < 0.0001), but broths containing Bifidobacterium or Lactobacillus virtually made sperm immotile. Although broth containing Salmonella, Campylobacter, and Bifidobacterium immediately reduced sperm motility, the reduction did not change over time. Broths containing E. coli, Clostridium, and Lactobacillus reduced sperm motility immediately, but over time motility continued to decrease. However, pH was increased when semen was exposed to the E. coli and Campylobacter treatment, but when semen was exposed to Bifidobacterium and Lactobacillus treatments, pH was reduced. In conclusion, the results indicate that bacteria can reduce broiler breeder sperm motility upon exposure.

Evidence for horizontal and vertical transmission in Campylobacter passage from hen to her progeny

Campylobacter is an important human pathogen, and consumption of undercooked poultry has been linked to significant human illnesses. To reduce human illness, intervention strategies targeting Campylobacter reduction in poultry are in development. For more than a decade, there has been an ongoing national and international controversy about whether Campylobacter can pass from one generation of poultry to the next via the fertile egg. We recognize that there are numerous sources of Campylobacter entry into flocks of commercial poultry (including egg transmission), yet the environment is often cited as the only source. There has been an abundance of published research globally that refutes this contention, and this article lists and discusses many of them, along with other studies that support environment as the sole or primary source. One must remember that egg passage can mean more than vertical, transovarian transmission. Fecal bacteria, including Campylobacter, can contaminate the shell, shell membranes, and albumen of freshly laid fertile eggs. This contamination is drawn through the shell by temperature differential, aided by the presence of moisture (the "sweating" of the egg); then, when the chick emerges from the egg, it can ingest bacteria such as Campylobacter, become colonized, and spread this contamination to flock mates in the grow house. Improvements in cultural laboratory methods continue to advance our knowledge of the ecology of Campylobacter, and in the not-so-distant future, egg passage will not be a subject continuously debated but will be embraced, thus allowing the development and implementation of more effective intervention strategies.

Transmission OF Campylobacter coli in chicken embryos

Campylobacter coli is an important species involved in human cases of enteritis, and chickens are carriers of the pathogen mainly in developing country. The current study aimed to evaluate the transmission of C. coli and its pathogenic effects in chicken embryos. Breeder hens were inoculated intra-esophageally with C. coli isolated from chickens, and their eggs and embryos were analyzed for the presence of bacteria using real-time PCR and plate culture. The viability of embryos was verified. In parallel, SPF eggs were inoculated with C. coli in the air sac; after incubation, the embryos were submitted to the same analysis as the embryos from breeder hens. In embryos and fertile eggs from breeder hens, the bacterium was only identified by molecular methods; in the SPF eggs, however, the bacterium was detected by both techniques. The results showed no relationship between embryo mortality and positivity for C. coli in the embryos from breeder hens. However, the presence of bacteria is a cause of precocious mortality for SPF embryos. This study revealed that although the vertical transmission is a possible event, the bacteria can not grow in embryonic field samples.

Molecular epidemiology of Campylobacter isolates from poultry production units in southern Ireland

This study aimed to identify the sources and routes of transmission of Campylobacter in intensively reared poultry farms in the Republic of Ireland. Breeder flocks and their corresponding broilers housed in three growing facilities were screened for the presence of Campylobacter species from November 2006 through September 2007. All breeder flocks tested positive for Campylobacter species (with C. jejuni and C. coli being identified). Similarly, all broiler flocks also tested positive for Campylobacter by the end of the rearing period. Faecal and environmental samples were analyzed at regular intervals throughout the rearing period of each broiler flock. Campylobacter was not detected in the disinfected house, or in one-day old broiler chicks. Campylobacter jejuni was isolated from environmental samples including air, water puddles, adjacent broiler flocks and soil. A representative subset of isolates from each farm was selected for further characterization using flaA-SVR sub-typing and multi-locus sequence typing (MLST) to determine if same-species isolates from different sources were indistinguishable or not. Results obtained suggest that no evidence of vertical transmission existed and that adequate cleaning/disinfection of broiler houses contributed to the prevention of carryover and cross-contamination. Nonetheless, the environment appears to be a potential source of Campylobacter. The population structure of Campylobacter isolates from broiler farms in Southern Ireland was diverse and weakly clonal.

Development and stability of bacteriocin resistance in Campylobacter spp

AIMS

Several bacteriocins (BCNs) that were identified from chicken commensal bacteria dramatically reduced Campylobacter colonization in poultry and are being directed toward on-farm control of this important foodborne human pathogen. A recent study has shown that BCN resistance in Campylobacter jejuni is very difficult to develop in vitro. In this study, in vivo development and stability of BCN resistance in Campylobacter was examined.

METHODS AND RESULTS

Chickens infected with Camp. jejuni NCTC 11168 were treated with BCN E-760 at the dose of 5 mg kg(-1) body weight day(-1) via oral gavages for three consecutive days, which selected BCN-resistant (BCN(r)) mutants in the treated birds. However, all the in vivo-selected mutants only displayed low levels of resistance to BCN (MIC = 2-8 mg l(-1)) when compared to parent strain (MIC = 0.5 mg l(-1)). Inactivation of CmeABC efflux pump of the BCN(r) mutants led to increased susceptibility to BCN (8-32 fold MIC reduction). Three different BCN(r) Campylobacter strains (in vitro- or in vivo-derived) were examined for the stability of BCN resistance using both in vitro and in vivo systems. The low level of BCN resistance in these strains was not stable in vitro or in vivo in the absence of BCN selection pressure.

CONCLUSIONS

Usage of BCN E-760 only selected low-level BCN(r) Camp. jejuni mutants in vivo, and the low-level BCN resistance was not stable in vitro and in vivo.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study provides helpful information for risk assessment of the future practical application of the anti-Campylobacter BCNs in animals.

Drinking water as the source of Campylobacter coli infection in grandparent heavy breeders

The aim of the present study was the molecular identification of a common source of infection of Campylobacter coli in two grandparent breeder farms. Campylobacter jejuni and C. coli were isolated from well water and cloacal swabs from grandparent chickens. Colonies were genotyped using restriction fragment length polymorphism-flaA gene, pulsed field gel electrophoresis and multi-locus sequence typing. The same genotype of C. coli was found in both farms and in the well from which drinking water was supplied to the farms. The well water was epidemiologically linked as the source of C. coli infection. The molecular identification for epidemiological source-tracking of C. coli in breeder farms could aid in combating the colonization of this pathogen and therefore to reduce their incidence in human campylobacteriosis.

Advances in enteropathogen control in poultry production

Poultry meat has been associated frequently and consistently with the transmission of enteric pathogens, including Salmonella and Campylobacter. This association has resulted in the development of HACCP-based intervention strategies. These strategies (hurdles) begin with elite breeder flocks and filter down the production pyramid. These hurdles include those already established, such as biosecurity, vaccination, competitive exclusion, pre- and probiotics, feed and water control, and those more experimental, such as bacteriophage or immunoglobulin therapy. The reduction in enteropathogens entering the processing plant, which employs critical control points, further reduce the exposure of consumers to these organisms. The synergistic application of hurdles will result in an environment that is restrictive and detrimental to enteropathogen colonization and contamination.

Campylobacter coli naturally resistant to elevated levels of gentamicin as a marker strain in poultry research

Campylobacter inoculation studies are limited without a suitable marker strain. The lurpose of this study was to screen Campylobacter strains (n=2073) obtained from poultry carcass rinses through the Centers for Disease Control and Prevention's National Antimicrobial Resistant Monitoring System for resistance to gentamicin and evaluate one strain's efficacy as a marker. A C. coli strain was found resistant to gentamicin at >32 microg/ml. Gentamicin was incorporated into media (Campy-Cefex agar, Brucella agar, and blood agar) from 0 to 1000 microg/ml, and the upper level of gentamicin resistance was determined. C. coli strain's upper level of growth on Campy-Cefex plates, blood agar plates, and Brucella agar plates was 400, 300, and 200 pg/ml, respectively. Ceca and postpick carcass rinses were obtained and streaked onto Campy-Cefex agar at the above gentamicin levels to evaluate background microflora exclusion. Campy-Cefex agar containing gentamicin at 100 ag/ml prevented from the ceca, and reduced from the rinse, background microflora. The C. coli strain was orally or intracloacally inoculated into chicks. At 1, 3, and 6 weeks of age, inoculated broilers were removed and several tissue types sampled for the presence of the marker strain. At 6 weeks of age, 10 additional noninoculated penmates were sampled. The C. coli strain colonized chicks, disseminated to body tissues, colonized penmates, and persisted throughout the 6-week grow-out. The C. coli strain's unique characteristic, being resistant to high levels of gentamicin, allows for a marker that can be used in a wide range of Campylobacter research projects.

Incidence and ecology of Campylobacter jejuni and coli in animals

Since its initial emergence in the 1970s, Campylobacter has become one of the most common causative agents of bacterial foodborne illness. Campylobacter species readily colonize the gastrointestinal tracts of domestic, feral and wild animals and while they rarely cause clinical disease in food animals, they can produce severe acute gastroenteritis in humans. Prevalence of Campylobacter in food animals can exceed 80% thus challenging processors to employ post-harvest pathogen reduction strategies. Reduction of pathogens before arrival to the abattoir is also of interest because the implementation of pre-harvest interventions may compliment existing post-harvest control techniques to further diminish possible retail sources of infection. Such multiple hurdle approaches that simultaneously utilize pre- and post-harvest control techniques are expected to be the most effective approach for decreasing human illness associated with foodborne pathogens.

Campylobacter spp. in conventional broiler flocks in Northern Ireland: epidemiology and risk factors

Risk factors for Campylobacter infection in conventional broiler flocks in the time period up to the first removal of birds to slaughter were investigated over a maximum of five consecutive production cycles in a cohort of 88 broiler farms in Northern Ireland. Samples for Campylobacter culture, which consisted of 14 cloacal swabs per flock, were collected from one house on each farm prior to the first depopulation of birds. In total 388 flocks were sampled, of which 163 tested positive for Campylobacter spp. (42.0%; 95% CI 35.1-48.9%). Data on farm and flock variables were obtained from questionnaires and random-effects logistic regression modelling used to investigate the association between these and the Campylobacter status of flocks. Six variables, all of which were significant at p<0.05, were included in the final multivariable model. These included a combined variable on the presence of rodents on farms, which showed an increased odds of infection in flocks where the farmer reported having observed rodents during the production cycle (OR=2.1) and/or where rodent droppings were observed at the sampling visit (OR=2.9). Other variables that were significantly associated with an increased odds of infection included the age of the birds at sampling (odds ratio for its linear effect=1.16 for each day of increase in age), season (summer versus other seasons OR=2.0), farms with three or more broiler houses (OR=2.9 compared to those with one house), the frequency of footbath disinfectant changes (OR=2.5 for once weekly and OR=4.0 for less than once weekly compared to twice weekly changes) and a categorical variable on the standard of tidiness and cleanliness of the broiler house ante-room (OR=2.0 and OR=4.9 for flocks from houses with poorer standards). There was no significant evidence of direct carry-over of infection from one production cycle to the next, neither was there evidence of other farm species acting as a source of infection.

Retrospective study of Campylobacter infection in a zoological collection

Little is known about the epidemiology of Campylobacter spp. in wild animal populations. However, zoological collections can provide valuable insights. Using records from the Zoological Society of London Whipsnade Zoo compiled between 1990 and 2003, the roles of a range of biotic and abiotic factors associated with the occurrence of campylobacteriosis were investigated. The occurrence of campylobacteriosis varied widely across host taxonomic orders. Furthermore, in mammals, a combination of changes in both rainfall and temperature in the week preceding the onset of gastroenteritis were associated with isolation of Campylobacter from feces. In birds, there was a weak negative correlation between mean weekly rainfall and isolation of Campylobacter from feces. Importantly, in birds we found that the mean weekly rainfall 3 to 4 weeks before symptoms of gastroenteritis appeared was the best predictor of Campylobacter infection. Campylobacter-related gastroenteritis cases with mixed concurrent infections were positively associated with the presence of parasites (helminths and protozoans) in mammals, while in birds Campylobacter was associated with other concurrent bacterial infections rather than with the presence of helminths and protozoans. This study suggests that climatic elements are important factors associated with Campylobacter-related gastroenteritis. Further investigations are required to improve our understanding of Campylobacter epidemiology in captive wild animal populations.

Molecular Phylogeny of theflaAShort Variable Region AmongCampylobacter jejuniIsolates Collected During an Annual Evaluation of Poultry Flocks in the Southeastern United States

Production and processing samples were collected from eight commercial poultry flocks in the southeastern United States and examined for the presence of Campylobacter spp. In an effort to determine relatedness, recovered isolates were typed using flaA short variable region (SVR) DNA sequence analysis. Six of the eight production flocks tested were Campylobacter positive. In general, multiple Campylobacter flaA SVR types were present within a flock. Additionally, types found within a flock were also recovered from the final processed carcass. However, in two cases, the population of Campylobacter flaA SVR types on the processed carcass differed from those recovered from the production samples. Comparison of subtypes among flocks reared on different farms and during different seasons revealed that subtypes of Campylobacter spp. persisted throughout the year and in different locations. Environmental samples from seven of the eight farms tested were also Campylobacter positive. In one flock, a drag swab of the rearing facility was Campylobacter spp. positive while the flock and the final product were both negative. For the remaining sampling periods, environmental samples were positive for Campylobacter spp. concomitant with recovery of Campylobacter spp. from the chickens. In the remaining six flocks, the majority of environmental isolates recovered possessed flaA SVR types identical to isolates recovered from the birds, while in only one case, a recovered environmental isolate possessed a flaA SVR type that was not related to isolates obtained from the flock. Interpretation of these data suggest that the external environment and the poultry production environment share common subtypes of Campylobacter spp. and that these subtypes can contribute to contamination of the final commercial product.

Recovery of Campylobacter from commercial broiler hatchery trayliners

Previous research has identified Campylobacter as one of the leading causes of foodborne illness. Poultry and poultry products have been identified as a major source of Campylobacter in human infections. Although many risk factors that contribute to Campylobacter levels have been identified, precise identification of the most effective sites for intervention has not been established. Epidemiological studies have identified that Campylobacter in the broiler breeder's reproductive tract, fertile eggs, and 2- to 3-wk-old broilers has the potential to contaminate day-of-hatch chicks. Numerous studies have shown that day-of-hatch broilers are Campylobacter-negative using conventional culture methods. The purpose of the present study was to demonstrate the prevalence of Campylobacter found in day-of-hatch broilers using a peptone water preenrichment followed by conventional Campylobacter culture methods. Using conventional tray liner (hatcheries) culture methods, the isolation distribution of Campylobacter from 8 commercial broiler hatcheries (n = 2,000) was evaluated. A total of 15 tray liners were positive from 3 different hatcheries. Of the 2,000 chick paper pad tray liners sampled, 0.75% were positive for Campylobacter. These data support previous findings indicating the potential for Campylobacter to be spread by vertical transmission. This is the first time that Campylobacter has been recovered from tray liners collected at commercial broiler hatcheries.

Natural presence of Campylobacter spp. in various internal organs of commercial broiler breeder hens

Campylobacter are known to cause acute bacterial gastroenteritis in humans. Poultry products have been implicated as a significant source of these infections. Six experiments were performed to determine whether Campylobacter could be isolated naturally from the primary and secondary lymphoid organs, liver/gallbladder, and ceca of commercial broiler breeder hens. Broiler breeder hens were acquired from different commercial sources during the early, middle, and late lay cycles. The birds were euthanatized, defeathered, and aseptically opened. To reduce the possibility of cross-contamination between samples, the thymus, spleen, and liver/gallbladder were aseptically removed prior to removal of the ceca. Individual samples were placed in sterile bags, packed on ice, and transported to the laboratory for evaluation. In this study Campylobacter were found in 11 of 43 thymii, eight of 43 spleens, four of 43 liver/gallbladders, and 30 of 43 ceca. Overall, 28 of 53 isolates from the above samples were Campylobacter coli and 25 of 53 isolates were found to be Campylobacter jejuni.

Lack of evidence for vertical transmission of Campylobacter spp. in chickens

Campylobacter jejuni is a major cause of bacterial food-borne infection in the industrial world. There is evidence that C. jejuni is present in eggs and hatchery fluff, opening the possibility for vertical transmission from hens to progeny. Poultry operations in Iceland provide an excellent opportunity to study this possibility, since breeding flocks are established solely from eggs imported from grandparent flocks in Sweden. This leaves limited opportunity for grandparents and their progeny to share isolates through horizontal transmission. While Campylobacter was not detected in all grandparent flocks, 13 of the 16 egg import lots consisted of eggs gathered from one or more Campylobacter-positive grandparent flocks. No evidence of Campylobacter was found by PCR in any of the 10 relevant quarantine hatchery fluff samples examined, and no Campylobacter was isolated from the parent birds through 8 weeks, while they were still in quarantine rearing facilities. After the birds were moved to less biosecure rearing facilities, Campylobacter was isolated, and 29 alleles were observed among the 224 isolates studied. While three alleles were found in both Sweden and Iceland, in no case was the same allele found both in a particular grandparent flock and in its progeny. We could find no evidence for vertical transmission of Campylobacter to the approximately 60,000 progeny parent breeders that were hatched from eggs coming from Campylobacter-positive grandparent flocks. If vertical transmission is occurring, it is not a significant source for the contamination of chicken flocks with Campylobacter spp.

Reducing the Carriage of Foodborne Pathogens in Livestock and Poultry

Several foodborne pathogens, including Salmonella species and campylobacters, are common contaminants in poultry and livestock. Typically, these pathogens are carried in the animal's intestinal tract asymptomatically; however, they can be shed in feces in large populations and be transmitted by other vectors from feces to animals, produce, or humans. A wide array of interventions has been developed to reduce the carriage of foodborne pathogens in poultry and livestock, including genetic selection of animals resistant to colonization, treatments to prevent vertical transmission of enteric pathogens, sanitation practices to prevent contamination on the farm and during transportation, elimination of pathogens from feed and water, feed and water additives that create an adverse environment for colonization by the pathogen, and biological treatments that directly or indirectly inactivate the pathogen within the host. To successfully reduce the carriage of foodborne pathogens, it is likely that a combination of intervention strategies will be required.

Risk factors for Campylobacter spp. colonization in broiler flocks in Iceland

We sampled 1,091 Icelandic broiler flocks at slaughter from May 2001 to December 2003 to determine the prevalence of, and investigate risk factors for the presence of, Campylobacter spp. at the flock level. Approximately 15% of the flocks were positive for Campylobacter spp.; most (95%) of the infected flocks being raised during the months of April-September. Based on the data from the latter months, and using multivariable logistic regression with random effects for herd, we found that the odds of a flock being positive for Campylobacter spp. increased with age and flock size. Additionally, vertical ventilation systems were strongly associated with positive flocks (OR=5.3). After controlling for these variables, we found no evidence of an effect of: year; company; Campylobacter being carried over from one flock to the next; time interval between flocks; using (at the hatcheries) eggs laid on the floor; density of bird housing, or the number of catch lots a flock was divided into for slaughtering purposes on the risk of a Campylobacter-positive flock.

Campylobacter jejuni infection in broiler chickens

Day-old, straight-run broiler chickens were procured from a hatchery located in the Pacific Northwest. The chickens were subdivided individually into nine groups of 20 chickens. The chickens were tagged, housed in isolation chambers on wire, fed commercial broiler feed, and given water ad libitum. Three isolates of Campylobacter jejuni of poultry origin and one of human origin were tested in this study. Various C. jejuni cultures were inoculated into 9-day-old chickens by crop gavage. Four groups of 20 chickens were inoculated at a dose level of 0.5 ml of 1 x 10(2) colony-forming units (CFU)/ml. The other four groups were inoculated with 0.5 ml of 1 X 10(4) CFU/ml. One group of 20 chickens was kept as an uninoculated control group. Four randomly selected chickens from each of the inoculated and uninoculated groups were necropsied at 5, 12, and 19 days postinoculation (DPI). The C. jejuni was cultured and enumerated from a composite of the upper and midintestine and the cecum. Body weights of all chicken groups at 7 days of age and at 5, 12, and 19 DPI were measured and statistically analyzed. No significant differences were present in the mean body weights (MBWs) of 7-day-old, 5 DPI, and 12 DPI male and female broiler chickens inoculated with C. jejuni at both dose levels compared with uninoculated controls. Differences in MBWs of the male and female broilers at 19 DPI were observed in some of the groups. Results of the C. jejuni culture enumeration mean (CEM) of composite intestine samples at 5 DPI from all inoculated chicken groups, irrespective of the dose level, ranged from (2.5 +/- 5.0) x 10(2) to (2.8 +/- 4.8) x 10(5) CFU/g (mean +/- SD). Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. CEM results from the composite intestine samples at 12 and 19 DPI increased by 1 log unit, or sometimes more. Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. Increases of 2-5 log units in C. jejuni CEM was present in chicken groups inoculated with 1 X 10(2) CFU of C. jejuni, and a 2- to 3-log increase was present in groups inoculated with a higher dose level of C. jejuni at 12 DPI. The results of C. jejuni CEM from cecal samples at 19 DPI were similar to chicken groups at 12 DPI. Campylobacterjejuni was not isolated from the uninoculated control chickens at 5, 12, and 19 DPI. Clinical signs of illness or gross pathologic lesions were not present in any of the chicken groups during this study. No lesions were present on histopathologic evaluations in C. jejuni-inoculated chickens or uninoculated control chickens.

Dissemination of fluoroquinolone-resistant Campylobacter spp. within an integrated commercial poultry production system

While characterizing the intestinal bacterial community of broiler chickens, we detected epsilon-proteobacterial DNA in the ilea of 3-day-old commercial broiler chicks (J. Lu, U. Idris, B. Harmon, C. Hofacre, J. J. Maurer, and M. D. Lee, Appl. Environ. Microbiol. 69:6816-6824, 2003). The sequences exhibited high levels of similarity to Campylobacter jejuni and Campylobacter coli sequences, suggesting that chickens can carry Campylobacter at a very young age. Campylobacter sp. was detected by PCR in all samples collected from the ilea of chicks that were 3 to 49 days old; however, it was detected only in the cecal contents of chickens that were at least 21 days old. In order to determine whether the presence of Campylobacter DNA in young chicks was due to ingestion of the bacteria in food or water, we obtained commercial broiler hatching eggs, which were incubated in a research facility until the chicks hatched. DNA sequencing of the amplicons resulting from Campylobacter-specific 16S PCR performed with the ileal, cecal, and yolk contents of the day-of-hatching chicks revealed that Campylobacter DNA was present before the chicks consumed food or water. The 16S rRNA sequences exhibited 99% similarity to C. jejuni and C. coli sequences and 95 to 98% similarity to sequences of other thermophilic Campylobacter species, such as C. lari and C. upsaliensis. The presence of C. coli DNA was detected by specific PCR in the samples from chicks obtained from a commercial hatchery; however, no Campylobacter was detected by culturing. In order to determine whether the same strains of bacteria were present in multiple levels of the integrator, we cultured Campylobacter sp. from a flock of broiler breeders and their 6-week-old progeny that resided on a commercial broiler farm. The broiler breeders had been given fluoroquinolone antibiotics, and we sought to determine whether the same fluoroquinolone-resistant strain was present in their progeny. The isolates were typed by pulsed-field gel electrophoresis, which confirmed that the parental and progeny flocks contained the same strain of fluoroquinolone-resistant C. coli. These data indicate that resistant C. coli can be present in multiple levels of an integrated poultry system and demonstrated that molecular techniques or more sensitive culture methods may be necessary to detect early colonization by Campylobacter in broiler chicks.

Apparent Attachment of Campylobacter and Salmonella to Broiler Breeder Rooster Spermatozoa

It has been demonstrated that horizontal and vertical transmission of Salmonella and Campylobacter can occur in broiler breeder flocks. The mechanism of this transmission is still unclear. Previously negative broiler breeder flocks have been reported to become positive with Salmonella, Campylobacter, or both after the introduction of "spike" roosters at 45 wk of age. To determine whether the rooster semen is a possible source of transmission to hens for colonization, we evaluated the association of both Salmonella and Campylobacter spp. to segments (head, midpiece, and tail) of individual spermatozoa after artificial inoculation. Salmonella typhimurium, Salmonella heidelberg, and Salmonella montevideo, or Campylobacter jejuni (in 0.85% saline) was added to a freshly collected (by abdominal massage) aliquot of pooled semen from roosters housed in individual cages. The semen and bacteria solutions were incubated 1 h at room temperature. Samples were fixed using Karnosvsky and Zamboni fixatives for 24 h prior to centrifuging and rinsing in 0.1 M cacodylate x HCl buffer. Individual aliquot samples were then subjected to both scanning (JSM-5800) and transmission (JEM-1210) electron microscopy. The scanning electron microscopy showed that Salmonella was associated with all 3 segments (head, midpiece, and tail) of the spermatozoa and apparently equally distributed. Campylobacter was mainly associated with the midpiece and tail segments; few isolates were located on the head segment. The transmission electron microscopy showed apparent attachment of Salmonella and Campylobacter to the spermatozoa.

Dynamics of Campylobacter spp. spread investigated in 14 broiler flocks in Switzerland

Ten conventional and four extensive outdoor broiler flocks, distributed over nine farms, were investigated twice per week during a 35-58-day rearing period to observe the dynamics of Campylobacter spp. spread within these flocks. Strains isolated during this period were genotyped by restriction fragment length polymorphism analysis of the flaA gene and macrorestriction profiling with pulsed field gel electrophoresis. A total of 4112 samples were collected; 157 (3.8%) of these samples were Campylobacter positive, with all C. jejuni. The positive samples were distributed over three conventional and two extensive outdoor flocks on five farms. These five positive flocks were colonized from the fifth to the seventh week of age and remained colonized until slaughter. Each of the flocks showed a flock-specific genotype of Campylobacter that predominated until slaughter. Presuming different ways of entry, a combination of this fact and the observed dynamics of C. jejuni spread within the flocks indicates that a single source from the environment may have been responsible for the colonization of each flock. These conclusions may serve to further develop combat strategies at farm level.

Differentiation of campylobacter populations as demonstrated by flagellin short variable region sequences

The DNA sequence of the flaA short variable region (SVR) was used to analyze a random population of Campylobacter isolates to investigate the weakly clonal population structure of members of the genus. The SVR sequence from 197 strains of C. jejuni and C. coli isolated from humans, bovine, swine, and chickens identified a group of 43 strains containing disparate short variable region sequences compared to the rest of the population. This group contains both C. jejuni and C. coli strains but disproportionately consisted of bovine isolates. Relative synonymous codon usage analysis of the sequences identified two groups: one group typified C. jejuni, and the second group was characteristic for C. coli and the disparate alleles were not clustered. The data show that there is significant differentiation of Campylobacter populations according to the source of the isolate even without considering the disparate isolates. Even though there is significant differentiation of chicken and bovine isolates, the bovine isolates did not show any difference in ability to colonize chickens. It is possible that disparate sequences were obtained through the lateral transfer of DNA from Campylobacter species other than C. jejuni and C. coli. It is evident that recombination within the flaA SVR occurs rapidly. However, the rate of migration between populations appears to limit the distribution of sequences and results in a weakly clonal population structure.

Presence of Naturally Occurring Campylobacter and Salmonella in the Mature and Immature Ovarian Follicles of Late-Life Broiler Breeder Hens

Campylobacter and Salmonella are known to cause acute bacterial gastroenteritis in humans. Raw poultry products have been implicated as a significant source of these infections. Five trials were conducted to determine whether Campylobacter and Salmonella spp. exist naturally in the mature and immature ovarian follicles of late-life broiler breeder hens. Broiler breeder hens ranging from 60 to 66 wk of age were obtained from four different commercial breeder operations. For each trial, the hens were removed from the commercial operation and held overnight at the University of Georgia processing facility. The hens were euthanized, defeathered, and aseptically opened. To reduce the possibility of cross-contamination between samples, first the mature and immature ovarian follicles, then the ceca, were aseptically removed. Individual samples were placed in sterile bags, packed on ice, and transported to the laboratory for evaluation. Overall, Campylobacter was found in 7 of 55 immature follicles, 12 of 47 mature follicles, and 41 of 55 ceca. Campylobacter was found in at least one of each sample of mature follicles and in ceca in each of the five trials. Salmonella was found in 0 of 55 immature follicles, 1 of 47 mature follicles, and 8 of 55 ceca. In this study, the recovery rate of Salmonella from late-life broiler breeder hen ovarian follicles was relatively low. However, the recovery rate of Campylobacter from the hen ovarian follicles was reasonably high, suggesting that these breeder hens could be infecting fertile hatching eggs. Determining how Campylobacter contaminated these ovarian follicles and how many chicks could be colonized from this source are the next steps in helping to elucidate a better understanding of this ecology and the control of Campylobacter in poultry production.

Presence of Campylobacter jejuni in various organs one hour, one day, and one week following oral or intracloacal inoculations of broiler chicks

Day-old broiler chicks (n=30) were obtained from a commercial hatchery and inoculated, either orally or intracloacally, with a characterized strain of Campylobacter jejuni. At 1 hr, 1 day, and 1 wk after inoculation, broilers (n = 5) from the orally and intracloacally inoculated groups along with control birds (n=4) were humanely killed by cervical dislocation. The broilers from the control and treatment groups were aseptically opened, and the thymus, spleen, liver/gallbladder, bursa of Fabricius, and ceca were aseptically removed and individually analyzed for C. jejuni. Overall, C. jejuni was isolated after oral inoculation from 13% (10/ 75), 17% (13/75), and 28% (14/50) of the 1-hr, 1-day, and 1-wk samples, respectively. Campylobacter jejuni was isolated from 10% (4/ 40), 8% (3/40), 10% (4/40), 25% (10/40), and 40% (16/40) of the thymus, spleen, liver/gallbladder, bursa of Fabricius, and ceca samples, respectively. Following the intracloacal route of inoculation, C. jejuni was recovered from 32% (24/75), 8% (6/75), and 16% (8/50) of the 1-hr, 1-day, and 1-wk samples, respectively. Campylobacter jejuni was isolated from 5% (2/40), 5% (2/40), 5% (2/40), 45% (18/40), and 40% (16/40) of the thymus, spleen, liver/gallbladder, bursa of Fabricius, and ceca samples, respectively, for all sampling periods. Campylobacter spp. were not recovered from sample sites examined from the control broilers from trial one, trial two, or trial three samples examined after 1 hr and 1 day. However, one control sample was positive from the 1-wk sampling from repetition three; therefore, those data were omitted. The rapid movement of Campylobacter to internal organs following both oral and intracloacal inoculation may be significant, particularly if it persists in these organs as reservoirs throughout the 65-wk life cycle of breeding birds.

Genotype dynamics of Campylobacter jejuni in a broiler flock

We investigated the genotype diversity and dynamics of Campylobacter in a commercial broiler flock during rearing and slaughter. In total, 220 Campylobacter jejuni isolates collected on four sampling occasions during rearing and from routine sampling during slaughter were subtyped by SmaI macrorestriction and pulsed-field gel electrophoresis, PFGE. Eight different SmaI types were found. During rearing, a subsequent addition of genotypes occurred, with two SmaI types found at 2 weeks of age and six types on the day before slaughter. All types that were detected in more than one isolate were also found on all succeeding sampling occasions, including the slaughter sampling. Two new types were found in the slaughter samples. In two-thirds of the individual birds sampled the day before slaughter, more than one SmaI type were found, although there was a clear tendency for dominance of one type in individual birds. Our results show that multiple genotypes of C. jejuni may be present in a commercial broiler flock during rearing and even in gastrointestinal tracts of individual birds. Both recurring environmental exposure and genetic changes within the population may explain the genotype diversity. Although the distribution of genotypes varied between different sampling occasions, we found no indication that any subtype excluded another during the rearing of the broiler flock.

Isolation and prevalence of Campylobacter in the reproductive tracts and semen of commercial turkeys

Campylobacter is one of the most commonly reported bacterial causes of human foodborne infections in the United States, and epidemiologic evidence indicates that a significant proportion of human infections result from the improper preparation of poultry products. Campylobacter frequently colonizes the avian intestinal tract, but recent research indicates that this organism can also colonize the avian reproductive tract and possibly contaminate eggs and subsequent offspring. The present studies were undertaken to determine the prevalence of Campylobacter in the reproductive systems of commercial turkeys. In the first study, pooled semen samples from seven commercial turkey farms were randomly collected by abdominal massage over a period of 13 wk. The pooled semen samples were serially diluted, and 0.1 ml of each dilution was plated on Campy-Line agar and incubated at 42 C for 48 hr in a microaerophilic environment for enumeration of Campylobacter. Campylobacter was isolated from 57 of the 59 pooled semen samples, and levels ranged from below the limit of detection (<10(1)) to 1.6 x 10(6) cfu/ml of semen. In the second study, the reproductive tracts of 11 hens and 17 toms were aseptically excised, and the segments (female: vagina, shell gland, isthmus, magnum, and infundibulum; male: ductus deferens and testes) were swabbed with a dry cotton sterile swab. The swabs were incubated for 24 hr in Campylobacter enrichment broth, and 0.1 ml of the enriched sample solution was streaked onto Campy-Line agar plates and incubated at 42 C for 48 hr in a microaerophilic environment. Of the 11 hens sampled, Campylobacter was isolated from the vagina (10/11), the shell gland (7/11), the isthmus (8/11), the magnum (6/11), and the infundibulum (4/11). Of the 17 toms sampled, Campylobacter was isolated from the ductus deferens (8/17) and the testes (2/17). Campylobacter is present in the reproductive tracts and semen of commercial turkeys and may lead to vertical transmission of Campylobacter from the hen to the chick.

Detection of Campylobacter or Salmonella in Turkey Semen and the Ability of Poultry Semen Extenders to Reduce Their Concentrations

Campylobacter and Salmonella are the most commonly reported pathogens causing foodborne illness in the United States. In turkeys, the potential that semen used for artificial insemination is contaminated with these foodborne pathogens has not been investigated. Because semen on turkey farms is pooled and then used to inseminate multiple hens, contaminated semen could easily spread these bacteria throughout entire flocks via artificial insemination. The objectives of this study were to 1) determine if semen from commercial turkey farms contained these foodborne pathogens and 2) if present, evaluate the efficacy of semen extenders to reduce or eliminate Campylobacter and Salmonella from semen. Semen was collected from randomized pools of ejaculates from 10 to 30 toms per farm from 6 flocks over a 7-wk period and, on occasion, was found to contain Campylobacter, Salmonella, or both. To evaluate the efficacy of semen extenders to reduce or eliminate pathogens, pooled ejaculates were challenged with Campylobacter or Salmonella and treated with commercial poultry extenders containing various concentrations of antibiotics or an antibiotic combination previously demonstrated to remove Campylobacter from mammalian semen. Results demonstrate that commercial turkey semen may contain Campylobacter or Salmonella, and the semen extenders tested either did not reduce the bacteria or reduced but did not eliminate these bacteria from semen. We concluded that semen may be a potential vehicle for Campylobacter transfer to hens, and, if this is true, development of a method for eliminating pathogens in semen before insemination could reduce the risk of colonization.

Effects of Aeration and Storage Temperature on Campylobacter Concentrations in Poultry Semen

Campylobacter is one of the most commonly reported bacterial causes of human foodborne infections in the United States. Recent evidence has demonstrated that Campylobacter is present in poultry semen and may contribute to the vertical transmission between the breeder hen and offspring. As Campylobacter is considered sensitive to oxygen and cold temperature, the objective of this study was to determine if aeration and storage temperature could reduce or eliminate Campylobacter in poultry semen. In 4 separate trials, pooled semen samples were collected from roosters or toms, diluted with a commercial poultry semen extender, and inoculated with an average of 10(7) cells/mL of a wild-type C. jejuni or C. coli semen isolate. Pooled ejaculates were then divided into 3 aeration treatments: Control (no aeration), air, or oxygen (gently bubbled for 20 min with atmospheric air or oxygen, respectively). Immediately after aeration, pooled semen samples were further divided to 3 test storage temperatures: 4, 23, or 42 degrees C. At 0, 2, 6, and 24 h of storage, samples were enumerated for Campylobacter. Aeration of the semen alone, or aeration with reduced temperatures (4 or 23 degrees C), did not reduce the amount of Campylobacter compared with the controls. Campylobacter concentrations were, however, reduced when stored at 42 degrees C for 24 h. This effect is associated with reduced sperm viability and is therefore not a practical treatment of reducing Campylobacter in semen. It appears alternative methods will be needed to eliminate Campylobacter from poultry semen.

Longitudinal study of Campylobacter jejuni bacteriophages and their hosts from broiler chickens

A longitudinal study of bacteriophages and their hosts was carried out at a broiler house that had been identified as having a population of Campylobacter-specific bacteriophages. Cloacal and excreta samples were collected from three successive broiler flocks reared in the same barn. Campylobacter jejuni was isolated from each flock, whereas bacteriophages could be isolated from flocks 1 and 2 but were not isolated from flock 3. The bacteriophages isolated from flocks 1 and 2 were closely related to each other in terms of host range, morphology, genome size, and genetic content. All Campylobacter isolates from flock 1 were genotypically indistinguishable by pulsed-field gel electrophoresis (PFGE). PFGE and multilocus sequence typing indicated that this C. jejuni type was maintained from flock 1 to flock 2 but was largely superseded by three genetically distinct C. jejuni types insensitive to the resident bacteriophages. All isolates from the third batch of birds were insensitive to bacteriophages and genotypically distinct. These results are significant because this is the first study of an environmental population of C. jejuni bacteriophages and their influence on the Campylobacter populations of broiler house chickens. The role of developing bacteriophage resistance was investigated as this is a possible obstacle to the use of bacteriophage therapy to reduce the numbers of campylobacters in chickens. In this broiler house succession was largely due to incursion of new genotypes rather than to de novo development of resistance.

Campylobacter colonization of sibling turkey flocks reared under different management conditions

Uncertainty exists concerning the key factors contributing to Campylobacter colonization of poultry, especially the possible role of vertical transmission from breeder hens to young birds. A longitudinal study of Campylobacter colonization was performed in two sibling pairs of turkey flocks (four flocks total). Each pair of sibling flocks shared breeder hen populations and was obtained from the same hatchery. One flock of each pair was grown on a commercial farm, and the other was grown in an instructional demonstration unit (Teaching Animal Unit [TAU]). Flocks were located within a 60-mi (96.8-km) radius. The time of placement, feed formulations, stocking density, and general husbandry were the same for both flocks, and each flock was processed at a commercial processing plant following standard feed withdrawal and transport protocols. Both flocks grown on the commercial farms became colonized with Campylobacter between weeks 2 and 3 and remained colonized until processing. Between 80 and 90% of isolates were Campylobacter coli, and the remainder were Campylobacter jejuni. In contrast, neither C. coli nor C. jejuni were isolated from either of the TAU flocks at any time during the production cycle. None of the fla types of Campylobacter from the breeders that provided poults to one of the commercial flocks matched those from the progeny. These results failed to provide evidence for vertical transmission and indicate that this type of transmission either did not occur or was not sufficient to render the TAU turkey flocks Campylobacter positive. Management practices such as proper litter maintenance, controlled traffic between the TAU farm and other turkey flocks, and other less well-defined aspects of turkey production were likely responsible for the absence of Campylobacter in the TAU flocks before harvest.

Detection and survival of Campylobacter in chicken eggs

AIMS

Campylobacter jejuni, a food-borne human pathogen, is widespread in poultry; however, the sources of infection and modes of transmission of this organism on chicken farms are not well understood. The objective of this study was to determine if vertical transmission of C. jejuni occurs via eggs.

METHODS AND RESULTS

Using a temperature differential method, it was shown that Campylobacter had limited ability to penetrate the eggshell. When C. jejuni was directly inoculated into the egg yolk and the eggs were stored at 18 degrees C, the organism was able to survive for up to 14 days. However, viability of C. jejuni was dramatically shortened when injected into the albumen or the air sac. When freshly laid eggs from Campylobacter-inoculated specific pathogen-free (SPF) layers were tested, C. jejuni-contamination was detected in three of 65 pooled whole eggs (5-10 eggs in each pool) via culture and PCR. However, the organism was not detected from any of the 800 eggs (80 pools), collected from the same SPF flock, but kept at 18 degrees C for 7 days before testing. Likewise, Campylobacter was not recovered from any of 500 fresh eggs obtained from commercial broiler-breeder flocks that were actively shedding Campylobacter in faeces. Also, none of the 1000 eggs from broiler breeders obtained from a commercial hatchery were positive for Campylobacter.

CONCLUSIONS

These results suggest that vertical transmission of C. jejuni through the egg is probably a rare event and does not play a major role in the introduction of Campylobacter to chicken flocks.

SIGNIFICANCE AND IMPACT OF THE STUDY

Control of Campylobacter transmission to chicken flocks should focus on sources of infection that are not related to eggs.

Cecal Colonization of Chicks by Bovine-Derived Strains of Campylobacter

Campylobacter jejuni and Campylobacter coli strains were isolated from feces of dairy cattle at farms with no known problem due to campylobacteria. Farms were located in the northeast, desert southwest, and Pacific west. Twenty isolates were identified by ribotyping with a RiboPrinter. The ability of these bovine isolates to colonize the ceca of chicks was determined by challenge inoculation and reisolation of the challenge strain from the ceca at 1 and 2 wk after challenge. Isolates recovered from chick ceca were examined by ribotyping to assure they matched the challenge strain. One hundred percent of the bovine-derived challenge strains were capable of colonizing chicks. These results indicate that dairy cattle may be asymptomatic Campylobacter carriers and potential sources of campylobacteria contamination of poultry facilities.