Reduction of Campylobacter jejuni in broiler chicken by successive application of group II and group III phages

BACKGROUND

Bacteriophage treatment is a promising tool to reduce Campylobacter in chickens. Several studies have been published where group II or group III phages were successfully applied. However, these two groups of phages are different regarding their host ranges and host cell receptors. Therefore, a concerted activity of group II and group III phages might enhance the efficacy of a treatment and decrease the number of resistant bacteria.

RESULTS

In this study we have compared the lytic properties of some group II and group III phages and analysed the suitability of various phages for a reduction of C. jejuni in broiler chickens. We show that group II and group III phages exhibit different kinetics of infection. Two group III and one group II phage were selected for animal experiments and administered in different combinations to three groups of chickens, each containing ten birds. While group III phage CP14 alone reduced Campylobacter counts by more than 1 log10 unit, the concomitant administration of a second group III phage (CP81) did not yield any reduction, probably due to the development of resistance induced by this phage. One group of chickens received phage CP14 and, 24 hours later, group II phage CP68. In this group of animals, Campylobacter counts were reduced by more than 3 log10 units.

CONCLUSION

The experiments illustrated that Campylobacter phage cocktails have to be carefully composed to achieve the best results.

Reducing Campylobacter jejuni colonization of poultry via vaccination

Campylobacter jejuni is a leading bacterial cause of human gastrointestinal disease worldwide. While C. jejuni is a commensal organism in chickens, case-studies have demonstrated a link between infection with C. jejuni and the consumption of foods that have been cross-contaminated with raw or undercooked poultry. We hypothesized that vaccination of chickens with C. jejuni surface-exposed colonization proteins (SECPs) would reduce the ability of C. jejuni to colonize chickens, thereby reducing the contamination of poultry products at the retail level and potentially providing a safer food product for consumers. To test our hypothesis, we injected chickens with recombinant C. jejuni peptides from CadF, FlaA, FlpA, CmeC, and a CadF-FlaA-FlpA fusion protein. Seven days following challenge, chickens were necropsied and cecal contents were serially diluted and plated to determine the number of C. jejuni per gram of material. The sera from the chickens were also analyzed to determine the concentration and specificity of antibodies reactive against the C. jejuni SECPs. Vaccination of chickens with the CadF, FlaA, and FlpA peptides resulted in a reduction in the number of C. jejuni in the ceca compared to the non-vaccinated C. jejuni-challenged group. The greatest reduction in C. jejuni colonization was observed in chickens injected with the FlaA, FlpA, or CadF-FlaA-FlpA fusion proteins. Vaccination of chickens with different SECPs resulted in the production of C. jejuni-specific IgY antibodies. In summary, we show that the vaccination of poultry with individual C. jejuni SECPs or a combination of SECPs provides protection of chickens from C. jejuni colonization.

A waterborne outbreak of campylobacteriosis in the South Island of New Zealand due to a failure to implement a multi-barrier approach

Outbreaks of waterborne gastroenteritis continue to occur in developed countries. Darfield, a rural town in the South Island of New Zealand experienced an outbreak of campylobacteriosis following a transgression of Escherichia coli on 16 August 2012. A descriptive outbreak investigation was performed. As a result, 29 cases had a laboratory-confirmed diagnosis of campylobacteriosis and 138 were identified as probable cases. Heavy rains, contamination of water with animal effluent from nearby paddocks and failures in the treatment of drinking water led to pathogens being distributed through the town's water supply. A multi-barrier approach is advocated to ensure the quality of water and many countries have legislation or programmes to address this. Although legislation for water safety plans based on a multi-barrier approach is in place in New Zealand, at the time of the outbreak it was not a requirement for the Darfield water supply. In addition, despite the awareness of the importance of a multi-barrier approach, competing interests, including those from the agricultural industry and financial restraints on water suppliers, can prevent it from being implemented. Governments need to be more willing to enforce legislation and standards to protect the public from waterborne disease.

An assessment of risk posed by a Campylobacter-positive puppy living in an Australian residential aged-care facility

INTRODUCTION

In April and June 2012, two outbreaks of Campylobacter gastroenteritis were investigated in an Australian aged-care facility (ACF); a Campylobacter-positive puppy was identified as a potential source of infection.

METHODS

An expert panel was convened to assess transmission risk from the puppy to elderly residents and to guide further public health action. Criteria considered as part of the panel's assessment included the puppy's infectivity, the bacterium's transmissibility, puppy-resident contact, infection control and cleaning practices and animal management at the facility. A literature review was used to assist the panel, with a final risk being determined using a likelihood and consequence matrix.

RESULTS

The panel determined that the setting and low infective dose made transmission likely despite varying degrees of contact between the puppy and cases. While infection control practices were generally appropriate, the facility's animal policy did not adequately address potential zoonotic risk.

CONCLUSION

In summary, puppies should not be considered as companion animals in ACFs due to high rates of Campylobacter carriage and the underlying susceptibility of the elderly. Infection control and animal policies in ACFs should reflect an awareness of zoonotic disease potential.

[Evaluation of immunological efficiency induced by Campylobacter jejuni PEB1 DNA combined with PEB1 protein in mice]

OBJECTIVE

To explore the improved immunological responses induced by an amino acid ABC transporter, permease protein PEB1 DNA vaccine primer-protein boost immunization method against Campylobacter jejuni.

METHODS

The DNA vaccine pcDNA3.1(-)-PEB1 and protein vaccine were prepared, respectively. The female BALB/c mice were intranasally immunized with the vaccines. PBS and pcDNA3.1(-) were used as controls. The humoral and cellular immunological responses were detected in female BALB/c mice that were challenged by Campylobacter jejuni at 28 days after the final immunization.

RESULTS

In the DNA primer-protein boost group at day 56, the stimulation index (SI) of lymphocytes was 2.625±0.275, serum IgG was (2.507±0.124) μg/mL, IL-4 in spleen supernatant was (377.47±14.560) pg/mL, IFN-γ in spleen supernatant was (258.920±13.472) pg/mL, and sIgA in genital tract was (80.351±5.769) ng/mL. All of them were significantly higher than those in controls (P<0.05). The DNA primer-protein boost vaccines induced the strongest levels of protection to BALB/c mice (91.53%).

CONCLUSION

The DNA primer-protein boost immunization could induce significant protective immunity against Campylobacter jejuni challenge. It could significantly enhance both humoral and cellular immunologic responses in BALB/c mice, compared with DNA vaccine or protein vaccine immunization alone.

Determining the health benefits of poultry industry compliance measures: the case of campylobacteriosis regulation in New Zealand

I undertake a cost benefit analysis of the food safety regulation of production of poultry for the New Zealand domestic market and the reduction in foodborne illness following this. I take a societal perspective to demonstrate that regulation brings both benefits and costs. I derive a cost of illness (COI) estimate of foodborne campylobacteriosis from three previous studies. I apply a cost benefit analysis (CBA) to this estimate, combined with the cost data supplied by industry and the regulator. The benefit:cost ratio was remarkable, showing a good return from the combined efforts of industry and the regulator in reduction of campylobacteriosis; in dollar terms a gain of at least $57.4 million annually. In summary the study demonstrates the high value to the New Zealand economy of investment in food safety compliance at the primary industry level.

Passive immunization to reduce Campylobacter jejuni colonization and transmission in broiler chickens

Campylobacter jejuni is the most common cause of bacterium-mediated diarrheal disease in humans worldwide. Poultry products are considered the most important source of C. jejuni infections in humans but to date no effective strategy exists to eradicate this zoonotic pathogen from poultry production. Here, the potential use of passive immunization to reduce Campylobacter colonization in broiler chicks was examined. For this purpose, laying hens were immunized with either a whole-cell lysate or the hydrophobic protein fraction of C. jejuni and their eggs were collected. In vitro tests validated the induction of specific ImmunoglobulinY (IgY) against C. jejuni in the immunized hens' egg yolks, in particular. In seeder experiments, preventive administration of hyperimmune egg yolk significantly (P < 0.01) reduced bacterial counts of seeder animals three days after oral inoculation with approximately 104 cfu C. jejuni, compared with control birds. Moreover, transmission to non-seeder birds was dramatically reduced (hydrophobic protein fraction) or even completely prevented (whole-cell lysate). Purified IgY promoted bacterial binding to chicken intestinal mucus, suggesting enhanced mucosal clearance in vivo. Western blot analysis in combination with mass spectrometry after two-dimensional gel-electrophoresis revealed immunodominant antigens of C. jejuni that are involved in a variety of cell functions, including chemotaxis and adhesion. Some of these (AtpA, EF-Tu, GroEL and CtpA) are highly conserved proteins and could be promising targets for the development of subunit vaccines.

Evaluation of the immunogenicity of Campylobacter jejuni CjaA protein delivered by Salmonella enterica sv. Typhimurium strain with regulated delayed attenuation in chickens

Campylobacter spp. are regarded as the most common bacterial cause of gastroenteritis worldwide, and consumption of chicken meat contaminated by Campylobacter is considered to be one of the most frequent sources of human infection in developed countries. Here we evaluated the immunogenicity and protective efficacy of Salmonella Typhimurium χ9718 producing the Campylobacter jejuni CjaA protein as a chicken anti-Campylobacter vaccine. In this study chickens were orally immunized with a new generation S. Typhimurium strain χ9718 with regulated delayed attenuation in vivo and displaying delayed antigen expression. The immunization with the S. Typhimurium χ9718 strain producing C. jejuni CjaA antigen induced strong immune responses against CjaA in both serum IgY and intestinal IgA, however, it did not result in the significant reduction of intestinal colonization by Campylobacter strain. The low level of protection might arise due to a lack of T cell response. Our results demonstrated that a Salmonella strain with regulated delayed attenuation and displaying regulated delayed antigen expression might be an efficient vector to induce immune response against Campylobacter. It seems that an efficient anti-Campylobacter subunit vaccine should be multicomponent. Since S. Typhimurium χ9718 contains two compatible balanced-lethal plasmids, it can provide the opportunity of cloning several Campylobacter genes encoding immunodominant proteins. It may also be used as a delivery vector of eukaryotic genes encoding immunostimulatory molecules to enhance or modulate functioning of chicken immune system.

Pentavalent single-domain antibodies reduce Campylobacter jejuni motility and colonization in chickens

Campylobacter jejuni is the leading cause of bacterial foodborne illness in the world, with symptoms ranging from acute diarrhea to severe neurological disorders. Contaminated poultry meat is a major source of C. jejuni infection, and therefore, strategies to reduce this organism in poultry, are expected to reduce the incidence of Campylobacter-associated diseases. We have investigated whether oral administration of C. jejuni-specific single-domain antibodies would reduce bacterial colonization levels in chickens. Llama single-domain antibodies specific for C. jejuni were isolated from a phage display library generated from the heavy chain IgG variable domain repertoire of a llama immunized with C. jejuni flagella. Two flagella-specific single-domain antibodies were pentamerized to yield high avidity antibodies capable of multivalent binding to the target antigen. When administered orally to C. jejuni-infected two-day old chicks, the pentabodies significantly reduced C. jejuni colonization in the ceca. In vitro, the motility of the bacteria was also reduced in the presence of the flagella-specific pentabodies, suggesting the mechanism of action is through either direct interference with flagellar motility or antibody-mediated aggregation. Fluorescent microscopy and Western blot analyses revealed specific binding of the anti-flagella pentabodies to the C. jejuni flagellin.

Harnessing the theoretical foundations of the exponential and beta-Poisson dose-response models to quantify parameter uncertainty using Markov Chain Monte Carlo

Dose-response models are the essential link between exposure assessment and computed risk values in quantitative microbial risk assessment, yet the uncertainty that is inherent to computed risks because the dose-response model parameters are estimated using limited epidemiological data is rarely quantified. Second-order risk characterization approaches incorporating uncertainty in dose-response model parameters can provide more complete information to decisionmakers by separating variability and uncertainty to quantify the uncertainty in computed risks. Therefore, the objective of this work is to develop procedures to sample from posterior distributions describing uncertainty in the parameters of exponential and beta-Poisson dose-response models using Bayes's theorem and Markov Chain Monte Carlo (in OpenBUGS). The theoretical origins of the beta-Poisson dose-response model are used to identify a decomposed version of the model that enables Bayesian analysis without the need to evaluate Kummer confluent hypergeometric functions. Herein, it is also established that the beta distribution in the beta-Poisson dose-response model cannot address variation among individual pathogens, criteria to validate use of the conventional approximation to the beta-Poisson model are proposed, and simple algorithms to evaluate actual beta-Poisson probabilities of infection are investigated. The developed MCMC procedures are applied to analysis of a case study data set, and it is demonstrated that an important region of the posterior distribution of the beta-Poisson dose-response model parameters is attributable to the absence of low-dose data. This region includes beta-Poisson models for which the conventional approximation is especially invalid and in which many beta distributions have an extreme shape with questionable plausibility.

Molecular-based surveillance of campylobacteriosis in New Zealand--from source attribution to genomic epidemiology

Molecular-based surveillance of campylobacteriosis in New Zealand contributed to the implementation of interventions that led to a 50% reduction in notified and hospitalised cases of the country's most important zoonosis. From a pre-intervention high of 384 per 100,000 population in 2006, incidence dropped by 50% in 2008; a reduction that has been sustained since. This article illustrates many aspects of the successful use of molecular-based surveillance, including the distinction between control-focused and strategy-focused surveillance and advances in source attribution. We discuss how microbial genetic data can enhance the understanding of epidemiological explanatory and response variables and thereby enrich the epidemiological analysis. Sequence data can be fitted to evolutionary and epidemiological models to gain new insights into pathogen evolution, the nature of associations between strains of pathogens and host species, and aspects of between-host transmission. With the advent of newer sequencing technologies and the availability of rapid, high-coverage genome sequence data, such techniques may be extended and refined within the emerging discipline of genomic epidemiology. The aim of this article is to summarise the experience gained in New Zealand with molecular-based surveillance of campylobacteriosis and to discuss how this experience could be used to further advance the use of molecular tools in surveillance.

A risk assessment of campylobacteriosis and salmonellosis linked to chicken meals prepared in households in Dakar, Senegal

We used a quantitative microbiological risk assessment model to describe the risk of Campylobacter and Salmonella infection linked to chicken meals prepared in households in Dakar, Senegal. The model uses data collected specifically for this study, such as the prevalence and level of bacteria on the neck skin of chickens bought in Dakar markets, time-temperature profiles recorded from purchase to consumption, an observational survey of meal preparation in private kitchens, and detection and enumeration of pathogens on kitchenware and cooks' hands. Thorough heating kills all bacteria present on chicken during cooking, but cross-contamination of cooked chicken or ready-to-eat food prepared for the meal via kitchenware and cooks' hands leads to a high expected frequency of pathogen ingestion. Additionally, significant growth of Salmonella is predicted during food storage at ambient temperature before and after meal preparation. These high exposures lead to a high estimated risk of campylobacteriosis and/or salmonellosis in Dakar households. The public health consequences could be amplified by the high level of antimicrobial resistance of Salmonella and Campylobacter observed in this setting. A significant decrease in the number of ingested bacteria and in the risk could be achieved through a reduction of the prevalence of chicken contamination at slaughter, and by the use of simple hygienic measures in the kitchen. There is an urgent need to reinforce the hygiene education of food handlers in Senegal.

Production of organic acids by probiotic lactobacilli can be used to reduce pathogen load in poultry

Probiotic Lactobacillus can be used to reduce the colonization of pathogenic bacteria in food animals, and therefore reduce the risk of foodborne illness to consumers. As a model system, we examined the mechanism of protection conferred by Lactobacillus species to inhibit C. jejuni growth in vitro and reduce colonization in broiler chickens. Possible mechanisms for the reduction of pathogens by lactobacilli include: 1) stimulation of adaptive immunity; 2) alteration of the cecal microbiome; and, 3) production of inhibitory metabolites, such as organic acids. The Lactobacillus species produced lactic acid at concentrations sufficient to kill C. jejuni in vitro. We determined that lactic acid produced by Lactobacillus disrupted the membrane of C. jejuni, as judged by biophotonics. The spectral features obtained using Fourier-transform infrared (FT-IR) and Raman spectroscopy techniques were used to accurately predict bacterial viability and differentiate C. jejuni samples according to lactic acid treatment. FT-IR spectral features of C. jejuni and Lactobacillus grown in co-culture revealed that the metabolism was dominated by Lactobacillus prior to the killing of C. jejuni. Based on our results, the development of future competitive exclusion strategies should include the evaluation of organic acid production.

[Basic research for the control of Campylobacter food poisoning]

Appropriate handling and controlled temperature prevent cross-contamination and proliferation of contaminants in foods, thereby reducing the incidences of food-borne gastroenteritis in Japan. However, the incidence of Campylobacter jejuni/coli infection did not markedly decrease and has become one of the major causes of food-borne diseases. C. jejuni and C. coli are widespread in warm-blooded domestic animals; therefore, food products may easily become contaminated during processing. C. jejuni and C. coli do not proliferate in foods, nor resistant to freezing, drying and oxidative stresses, and the number is greatly reduced under such conditions. These properties should be considered for risk management of Campylobacter in food processing and manufacturing.

Biosecurity-based interventions and strategies to reduce Campylobacter spp. on poultry farms

The prevention and control of Campylobacter colonization of poultry flocks are important public health strategies for the control of human campylobacteriosis. A critical review of the literature on interventions to control Campylobacter in poultry on farms was undertaken using a systematic approach. Although the focus of the review was on aspects appropriate to the United Kingdom poultry industry, the research reviewed was gathered from worldwide literature. Multiple electronic databases were employed to search the literature, in any language, from 1980 to September 2008. A primary set of 4,316 references was identified and scanned, using specific agreed-upon criteria, to select relevant references related to biosecurity-based interventions. The final library comprised 173 references. Identification of the sources of Campylobacter in poultry flocks was required to inform the development of targeted interventions to disrupt transmission routes. The approach used generally involved risk factor-based surveys related to culture-positive or -negative flocks, usually combined with a structured questionnaire. In addition, some studies, either in combination or independently, undertook intervention trials. Many of these studies were compromised by poor design, sampling, and statistical analysis. The evidence for each potential source and route of transmission on the poultry farm was reviewed critically, and the options for intervention were considered. The review concluded that, in most instances, biosecurity on conventional broiler farms can be enhanced and this should contribute to the reduction of flock colonization. However, complementary, non-biosecurity-based approaches will also be required in the future to maximize the reduction of Campylobacter-positive flocks at the farm level.

Development of flexible antimicrobial packaging materials against Campylobacter jejuni by incorporation of gallic acid into zein-based films

In this study, antimicrobial films were developed against Campylobacter jejuni by incorporation of gallic acid (GA) into zein-based films. The zein and zein-wax composite films containing GA between 2.5 and 10 mg/cm(2) were effective on different C. jejuni strains in a concentration-dependent manner. Zein and zein-wax composite films showed different release profiles in distilled water but quite similar release profiles at solid agar medium. Depending on incorporated GA concentration, 60-80% of GA released from the films, while the remaining GA was bound or trapped by film matrix. The GA at 2.5 and 5 mg/cm(2) caused a considerable increase in elongation (57-280%) of all zein films and eliminated their classical flexibility problems. The zein-wax composite films were less flexible than zein films, but the films showed similar tensile strengths and Young's modulus. Scanning electron microscopy indicated different morphologies of zein and zein-wax composite films. This study clearly showed the good potential of zein and GA to develop flexible antimicrobial films against C. jejuni.

Marked campylobacteriosis decline after interventions aimed at poultry, New Zealand

Beginning in the 1980s, New Zealand experienced rising annual rates of campylobacteriosis that peaked in 2006. We analyzed notification, hospitalization, and other data to explore the 2007-2008 drop in campylobacteriosis incidence. Source attribution techniques based on genotyping of Campylobacter jejuni isolates from patients and environmental sources were also used to examine the decline. In 2008, the annual campylobacteriosis notification rate was 161.5/100,000 population, representing a 54% decline compared with the average annual rate of 353.8/100,000 for 2002-2006. A similar decline was seen for hospitalizations. Source attribution findings demonstrated a 74% (95% credible interval 49%-94%) reduction in the number of cases attributed to poultry. These reductions coincided with the introduction of a range of voluntary and regulatory interventions to reduce Campylobacter spp. contamination of poultry. The apparent success of these interventions may inform approaches other countries could consider to help control foodborne campylobacteriosis.

The in vivo efficacy of two administration routes of a phage cocktail to reduce numbers of Campylobacter coli and Campylobacter jejuni in chickens

BACKGROUND

Poultry meat is one of the most important sources of human campylobacteriosis, an acute bacterial enteritis which is a major problem worldwide. Campylobacter coli and Campylobacter jejuni are the most common Campylobacter species associated with this disease. These pathogens live in the intestinal tract of most avian species and under commercial conditions they spread rapidly to infect a high proportion of the flock, which makes their treatment and prevention very difficult. Bacteriophages (phages) are naturally occurring predators of bacteria with high specificity and also the capacity to evolve to overcome bacterial resistance. Therefore phage therapy is a promising alternative to antibiotics in animal production. This study tested the efficacy of a phage cocktail composed of three phages for the control of poultry infected with C. coli and C. jejuni. Moreover, it evaluated the effectiveness of two routes of phage administration (by oral gavage and in feed) in order to provide additional information regarding their future use in a poultry unit.

RESULTS

The results indicate that experimental colonisation of chicks was successful and that the birds showed no signs of disease even at the highest dose of Campylobacter administered. The phage cocktail was able to reduce the titre of both C. coli and C. jejuni in faeces by approximately 2 log10 cfu/g when administered by oral gavage and in feed. This reduction persisted throughout the experimental period and neither pathogen regained their former numbers. The reduction in Campylobacter titre was achieved earlier (2 days post-phage administration) when the phage cocktail was incorporated in the birds' feed. Campylobacter strains resistant to phage infection were recovered from phage-treated chickens at a frequency of 13%. These resistant phenotypes did not exhibit a reduced ability to colonize the chicken guts and did not revert to sensitive types.

CONCLUSIONS

Our findings provide further evidence of the efficacy of phage therapy for the control of Campylobacter in poultry. The broad host range of the novel phage cocktail enabled it to target both C. jejuni and C. coli strains. Moreover the reduction of Campylobacter by approximately 2 log10cfu/g, as occurred in our study, could lead to a 30-fold reduction in the incidence of campylobacteriosis associated with consumption of chicken meals (according to mathematical models). To our knowledge this is the first report of phage being administered in feed to Campylobacter-infected chicks and our results show that it lead to an earlier and more sustainable reduction of Campylobacter than administration by oral gavage. Therefore the present study is of extreme importance as it has shown that administering phages to poultry via the food could be successful on a commercial scale.

[Application of risk assessment in process of standards establishment about campylobacter jejuni in chicken]

OBJECTIVE

According to risk assessment results of the Campylobacter jejuni in chicken of Chinese residents' dietary, from the point of the standard management, establish the feasible measures to reduce the risk.

METHODS

Half-quantity risk assessment of Risk Ranger was used.

RESULTS

Campylobacter jejuni usually could not reproduce in the processing environment or in the processed products of chicken. Currently, the risk of the likelihood that the urban people of our country have Campylobacter jejuni infections due to eating chicken was six times as that of the rural people.

CONCLUSION

There is no need to set a limit level for Campylobacter jejuni in the standard of chicken products. Control in the feeding, processing and preparation before eating of chicken are the important measures in reducing the Campylobacter jejuni infections caused by chicken.

Application of a group II Campylobacter bacteriophage to reduce strains of Campylobacter jejuni and Campylobacter coli colonizing broiler chickens

Members of the genus Campylobacter are frequently responsible for human enteric disease worldwide. Persistent Campylobacter contamination of poultry meat is a common problem that represents a significant food safety risk through the consumption of undercooked poultry meat or through cross-contamination of other foods during the preparation of poultry. Bacteriophage therapy is one possible means by which this colonization of poultry could be controlled, thus limiting the entry of Campylobacter into the human food chain. Previously group III phages with genome sizes of approximately 140 kb had been administered to Campylobacter jejuni-colonized poultry. The application of a group II Campylobacter phage, CP220, with a genome size of 197 kb is described here. Phage CP220 was administered to both C. jejuni- and C. coli-colonized birds. A 2-log CFU/g decline in cecal Campylobacter counts was observed after 48 h in birds colonized with C. jejuni HPC5 and administered with a single 7-log PFU dose of CP220. The incidence of phage resistance developing in Campylobacter-colonized chickens upon exposure to virulent phages was determined to be 2%, and the resistant types remained a minor component of the population. To achieve a similar reduction in Campylobacter numbers in C. coli OR12-colonized birds, a 9-log PFU dose of CP220 was required. Using phage to reduce Campylobacter colonization in poultry offers the prospect of a sustainable intervention measure that may limit the entry of these pathogens into the human food chain.

Capsule polysaccharide conjugate vaccine against diarrheal disease caused by Campylobacter jejuni

The capsule polysaccharide (CPS) of Campylobacter jejuni is one of the few identified virulence determinants of this important human pathogen. Since CPS conjugate vaccines have been so effective against other mucosal pathogens, we evaluated this approach using CPSs from two strains of C. jejuni, 81-176 (HS23 and HS36 serotype complex) and CG8486 (HS4 serotype complex). The CPSs of 81-176 and CG8486 were independently linked to the carrier protein CRM(197) by reductive amination between an aldehyde(s), strategically created at the nonreducing end of each CPS, and accessible amines of CRM(197). In both cases, the CPS:CRM(197) ratio used was 2:1 by weight. Mass spectrometry and gel electrophoresis showed that on average, each glycoconjugate preparation contained, at least in part, two to five CPSs attached to one CRM(197). When administered subcutaneously to mice, these vaccines elicited robust immune responses and significantly reduced the disease following intranasal challenge with the homologous strains of C. jejuni. The CPS(81-176)-CRM(197) vaccine also provided 100% protection against diarrhea in the New World monkey Aotus nancymaae following orogastric challenge with C. jejuni 81-176.

[Isolation of Campylobacter fetus from persons with obstetric-gynecological infections]

Campylobacter fetus subspecies fetus is a cause of different obstetric-gynecological diseases. It is a first time when rate of infection with Campylobacter was studied and connection between the infection and development of chronic gynecologic diseases and pathology of labor was established. Bacteria were isolated and identified in 36.0% +/- 0.7 of studied women admitted to inpatient clinics. It was established that Campylobacter fetus subspecies fetus can cause abnormalities in placenta functions as well as different inflammatory processes during pregnancy.

Cross-contamination in the kitchen: effect of hygiene measures

AIMS

To determine the effect of hygiene measures on cross-contamination of Campylobacter jejuni at home and to select a safe tracer organism for C. jejuni.

METHODS AND RESULTS

Comparative tests were conducted with nonpathogenic Escherichia coli and Lactobacillus casei and L. casei was chosen as the safe tracer organism. Salads containing chicken breast fillet contaminated with a known number of C. jejuni and L. casei were prepared according to different cross-contamination scenarios and contamination levels of salads were determined. Cross-contamination could be strongly reduced when cleaning cutting board and cutlery with hot water (68 degrees C), but generally was not prevented using consumer-style cleaning methods for hands and cutting board.

CONCLUSIONS

Dish-washing does not sufficiently prevent cross-contamination, thus different cutting boards for raw meat and other ingredients should be used and meat-hand contact should be avoided or hands should be thoroughly cleaned with soap. Lactobacillus casei can be used as a safe tracer organism for C. jejuni in consumer observational studies.

SIGNIFICANCE AND IMPACT OF THE STUDY

Cross-contamination plays an important role in the transmission of food-borne illness, especially for C. jejuni. This study delivers suitable data to quantitatively assess the risk of campylobacteriosis caused by cross-contamination and it shows the effect of different preventive hygiene measures.

Partial breastfeeding protects Bedouin infants from infection and morbidity: prospective cohort study

The benefits of exclusive breastfeeding for health in infants have been widely described. The goal of this study was to determine whether partial breastfeeding has protective effects against enteric infection and associated morbidity in population where early addition of supplementation is common. In this prospective study 238 Bedouin infants were followed from birth to age 18 months. Exclusive breastfeeding was protective against infection and morbidity at ages 0 to 3 months. In the age range of 4 to 6 months, partial versus non breastfeeding was associated with lower rates of infection with Cryptosporidium spp (Odds Ratio OR 0.34, 95% confidence interval CI 0.18; 0.65), and Campylobacter spp (OR 0.58, CI 0.35; 0.98), lower rates of ear infections (OR 0.47, CI 0.24; 0.90) and of asthma (OR 0.33, CI 0.13; 0.81). In older children (10-12 month age range) partial breastfeeding as compared to none, protected against infections with Cryptosporidium spp (OR 0.57, CI 0.36; 0.91) and Giardia lamblia (OR 0.92, CI 0.85; 0.99). In Bedouins, and possibly in other populations, even partial breastfeeding, especially at ages 4 to 6 months offers protection against infection. Thus, encouraging mothers to continue to at least partially breastfeed past age 3 months may help reduce infections and morbidity in infants.

[Experimental study on the chitosan-DNA vaccines against campylobacter jejuni invasion]

OBJECTIVE

The immunogenicity and protective efficacy of an experimental Campylobacter jejuni (C. jejuni) chitosan-DNA vaccines were evaluated in mice.

METHODS

The chitosan-DNA vaccines were prepared by embedding pcDNA3.1(+)-cadF and pcDNA3.1(+)-peblA with chitosan respectively. BALB/c mice were intranasally immunized in a four-dose primary series (7 d intervals) at doses of 60 microg chitosan-DNA vaccines each time. The comparative immunogenicities of nine formulations were assessed on the basis of the generation of antigen-specific antibodies in serum and intestinal secretions. Mice were attacked repeatedly through intragastric administration of C. jejuni HS:19 at the 8th week after the immunization and protective efficacy was determined by detecting the degrees of protection afforded against C. jejuni invaded.

RESULTS

The mice immunized with chitosan-DNA vaccines have generated high levels of IgA and IgG from the sera and IgA from the intestinal secretions and the P/N value went up to 20.58, 30.13 and 6.87 respectively. Meanwhile, the expression of intestinal SIgA increased correspondingly. Moreover the chitosan-DNA vaccines induced strongest level of protection in BALB/c mice against challenge with C. jejuni HS:19 strain and the protective efficacies was 93.70.

CONCLUSION

The results of this study indicate that the chitosan-DNA vaccines could induce significant protective immunity against C. jejuni challenge in the mice model.

[Food borne infectious outbreaks, Austria 2005]

In Austria, a total of 606 food borne outbreaks, affecting 1,910 people altogether (including 368 hospitalized patients and 1 fatal outcome) were documented in 2005. Salmonella spp. and Campylobacter spp. accounted for 99% of all reported outbreaks. Fortysix (8%) of the 606 outbreaks were acquired abroad. Bacteria caused all but one of the 560 domestically acquired food borne outbreaks: 427 (76%) were due to Salmonella spp., 128 (23%) due to Campylobacter spp. and two outbreaks each due to enterohaemorrhagic Escherichia coli and Yersinia enterocolitica. Norovirus caused an outbreak affecting 22 persons. The respective hospitalization rate for domestically acquired Salmonella spp. and Campylobacter spp. infections was 20% and 16%. Of those outbreaks where information as to the source was provided, eggs were implicated in 57%, meat products (especially poultry) in 30% and milk or dairy products (especially raw milk) in 4%. The ratio between family outbreaks and general outbreaks was 89% to 11%. For general outbreaks the following locations of exposure were given: commercial food suppliers (incl. restaurants, cafeterias) 34 x, family celebrations 14 x, nursery schools 4 x, festivities (e.g. fairs) 3 x, nursing homes twice and once a mixed outbreak involving commercial food suppliers plus homes (Austria-wide S. Enteritidis PT19 outbreak). In our opinion, the relatively high number of family outbreaks merely reflects the still insufficient quality of epidemiological outbreak investigation in Austria, i.e. lack of consolidating individual clusters into larger food borne outbreaks which exceed district or provincial borders.

Cost-utility analysis to control Campylobacter on chicken meat: dealing with data limitations

The current article describes the economic evaluation of interventions to control Campylobacter on chicken meat by means of a cost-utility analysis. Apart from the methodology used, the main focus of this article is on data gaps and assumptions made, and their impact on results and conclusions. The direct intervention costs, the relative risk, the disease burden (expressed in disability-adjusted life years (DALYs)), and the costs of illness for the various interventions are necessary inputs for the cost-utility analysis. The cost-utility ratio (CUR) -- the measure for efficiency -- is expressed in net costs per avoided DALY. Most data gaps were of a biological order, but for some interventions, information on costs was also scarce. As a consequence, assumptions had to be made, which had some impact on the estimated CUR. A higher (lower) incidence of Campylobacter infections associated with chicken meat, higher (lower) effectiveness, and lower (higher) intervention costs, respectively, would result in absolute better (worse) CUR estimates. By taking the perspective of all consumers eating Dutch chicken meat, rather than only the Dutch society, absolute better CUR estimates could be obtained. Indirect costs or a shift toward non-Dutch chicken meat would both result in higher CUR estimates. Despite the assumptions made, three interventions showed for most of the applied sensitivity analyses relatively favorable CUR estimates: limiting fecal leakage during processing, carcass decontamination by dipping in a chemical solution, and the phage therapy. However, all three do have some clauses.

A farm-level study of risk factors associated with the colonization of broiler flocks with Campylobacter spp. in Iceland, 2001-2004

BACKGROUND

Following increased rates of human campylobacteriosis in the late 1990's, and their apparent association with increased consumption of fresh chicken meat, a longitudinal study was conducted in Iceland to identify the means to decrease the frequency of broiler flock colonization with Campylobacter. Our objective in this study was to identify risk factors for flock colonization acting at the broiler farm level.

METHODS

Between May 2001 and September 2004, pooled caecal samples were obtained from 1,425 flocks at slaughter and cultured for Campylobacter. Due to the strong seasonal variation in flock prevalence, analyses were restricted to a subset of 792 flocks raised during the four summer seasons. Flock results were collapsed to the farm level, such that the number of positive flocks and the total number of flocks raised were summed for each farm. Logistic regression models were fitted to the data using automated and manual selection methods. Variables of interest included manure management, water source and treatment, other poultry/livestock on farm, and farm size and management.

RESULTS

The 792 flocks raised during the summer seasons originated from 83 houses on 33 farms, and of these, 217 (27.4%) tested positive. The median number of flocks per farm was 14, and the median number of positive flocks per farm was three. Three farms did not have any positive flocks. In general, factors associated with an increased risk of Campylobacter were increasing median flock size on the farm (p

CONCLUSION

Limiting the average flock size, and limiting the number of houses built on new farms, are interventions that require investigation. Water may play a role in the transmission of Campylobacter, therefore the use of official water, and potentially, treating non-official water may reduce the risk of colonization. Manure management practices deserve further attention.

Collapse

Key Words Collapse

MESH Headings

• Animal Husbandry/methods
• Animals
• Campylobacter/isolation & purification
• Campylobacter Infections/epidemiology
• Campylobacter Infections/etiology
• Campylobacter Infections/prevention & control
• Campylobacter Infections/veterinary
• Chickens
• Food Contamination/prevention & control
• Humans
• Iceland/epidemiology
• Logistic Models
• Manure/microbiology
• Population Density
• Poultry Diseases/epidemiology
• Poultry Diseases/etiology
• Poultry Diseases/prevention & control
• Prevalence
• Risk Factors
• Seasons
• Zoonoses

Collapse

Grants Collapse

Vaccination of chickens against Campylobacter

The gram-negative bacterium Campylobacter is the leading cause of bacterial entero-colitis in humans and is associated with the occurrence of life-threatening auto-immune based neurological disorders. Chickens, which are often heavily colonized with Campylobacter without signs of pathology, are considered the most important source for human infection. Although vaccination is a well established and effective method to combat various microbes in poultry, a commercial vaccine against Campylobacter has not yet been developed. For the development of such a vaccine, three main challenges can be identified: (1) the identification of novel cross-protection-inducing antigens, (2) the induction of a rapid, potent immune response, and (3) the development of novel adjuvants to further stimulate immunity against Campylobacter. The rapidly emerging knowledge of the biology of Campylobacter in combination with the recent advances in the fields of molecular vaccinology and immunology provide the required setting for the development of an effective vaccine against Campylobacter in poultry.

Current perceptions of travelers' diarrhea treatments and vaccines: results from a postal questionnaire survey and physician interviews

BACKGROUND

Travelers' diarrhea (TD) occurs at high frequency in individuals from industrialized countries visiting destinations in nonindustrialized countries and may result in chronic complications such as Guillain-Barré syndrome.

METHODS

We distributed a questionnaire requesting information on physicians' perceptions of currently available TD products, hypothesized TD vaccines, and aspects of travelers' behavior. Some physicians also were interviewed by telephone.

RESULTS

We obtained completed questionnaires from named individuals at 68 UK/US clinics. These individuals reported seeing a total of approximately 76,500 travelers per year, and estimated that 61% (UK) and 77% (US) of travelers present 2 weeks or more predeparture. More US (92%) than UK (43%) travelers are advised to purchase TD products. In both countries, 85% of travelers would be prescribed an ideal TD vaccine, but only approximately 47% (UK) and approximately 65% (US) would purchase this vaccine. About 80% of physicians would recommend an hypothesized 100% effective Campylobacter vaccine for travelers visiting regions where 30% of TD cases are caused by Campylobacter.

CONCLUSIONS

Physicians support the concept of TD vaccines, including campylobacteriosis vaccines. An ideal TD vaccine might be purchased by up to 16% (UK) and 28% (US) of relevant travelers. A 100% effective Campylobacter vaccine might be purchased by over 2 million UK/US travelers per year.

Potential competitive exclusion bacteria from poultry inhibitory to Campylobacter jejuni and Salmonella

The objective of this study was to isolate from chickens potential competitive exclusion bacteria (CE) that are inhibitory to Campylobacter jejuni or Salmonella, or to both, for subsequent development of a defined CE product for use in poultry. Adult chickens from family farms, commercial farms, and broiler chicken research centers were sampled to identify and select C. jejuni-free donor chickens. A challenge treatment, which included administering perorally 106 CFU C. jejuni per chicken and determining undetectable cecal shedding of campylobacters at 4 weeks, was important for identifying the best CE donor chickens. Screening of bacterial colonies obtained from nine donor chickens by using selective and nonselective media yielded 636 isolates inhibitory to six C. jejuni strains in vitro, with 194 isolates being strongly inhibitory. Of the 194 isolates, 145 were from ceca, and 117 were facultative anaerobic bacteria. One hundred forty-three isolates were inhibitory to six strains of Salmonella (including five different serotypes) in vitro. Of these, 41 were strongly inhibitory to all C. jejuni and Salmonella strains evaluated, and most were Lactobacillus salivarius. A direct overlay method, which involved directly applying soft agar on plates with discrete colonies from mucus scrapings of gastrointestinal tracts, was more effective in isolating CE than was the frequently practiced isolation method of picking and transferring discrete colonies and then overlaying them with soft agar. The best approach for obtaining bacteria highly inhibitory to Salmonella and C. jejuni from chickens was to isolate bacteria from ceca under anaerobic conditions. Free-range chickens from family farms were better donors of potential CE strongly inhibitory to both Salmonella and Campylobacter than were chickens from commercial farms and broiler chicken research centers.

Campylobacter jejuni proteomics for new travellers’ diarrhoea vaccines

Travellers' diarrhoea is defined as diarrhoea that develops while a person is abroad in or shortly after return from a developing country. Different pathogens cause diarrhoea in travellers. Campylobacter jejuni is one of the most prominent agents for this illness. Diarrhoea is defined as an abnormally increased frequency or decreased consistency of stools for less than one week. Antibiotics are effective in preventing travellers' diarrhoea, but routine prophylaxis with antibiotics, should be discouraged. Vaccination is promising but no vaccine against C. jejuni is available at the moment. This article presents the ACE BioSciences strategy for the discovery of protein based vaccine candidates using a cell surface proteomics approach of C. jejuni. New targets for C. jejuni protein vaccines were identified. As proof of concept, we could demonstrate decreased colonization of C. jejuni in mice after vaccination with some of these candidates. It is likely that the proteomics based ACE-Biosciences approach will result in reliable travellers' diarrhoea protein-vaccines in the future.

Fluoroquinolone-resistant Campylobacter species and the withdrawal of fluoroquinolones from use in poultry: a public health success story

Campylobacter species cause 1.4 million infections each year in the United States. Fluoroquinolones (e.g., ciprofloxacin) are commonly used in adults with Campylobacter infection and other infections. Fluoroquinolones (e.g., enrofloxacin) are also used in veterinary medicine. Human infections with fluoroquinolone-resistant Campylobacter species have become increasingly common and are associated with consumption of poultry. These findings, along with other data, prompted the US Food and Drug Administration to propose the withdrawal of fluoroquinolone use in poultry in 2000. A lengthy legal hearing concluded with an order to withdraw enrofloxacin from use in poultry (effective in September 2005). Clinicians are likely to continue to encounter patients with fluoroquinolone-resistant Campylobacter infection and other enteric infection because of the continued circulation of fluoroquinolone-resistant Campylobacter species in poultry flocks and in persons returning from foreign travel who have acquired a fluoroquinolone-resistant enteric infection while abroad. Judicious use of fluoroquinolones and other antimicrobial agents in human and veterinary medicine is essential to preserve the efficacy of these important chemotherapeutic agents.

Effect of oral administration of bismuth compounds on Campylobacter colonization in broilers

Bismuth compounds have been used since the 18th century to treat gastrointestinal ailments in man. Colloidal bismuth subcitrate (De-Nol) is currently used in combination with antibiotics to reduce enteric Helicobacter pylori colonization as a treatment of stomach ulcers. We investigated whether bismuth citrate or its parent compound, colloidal bismuth subcitrate, would reduce colonization of the closely related foodborne pathogen, Campylobacter jejuni in chickens. In 2 studies, birds were either fed 0, 50, or 200 ppm bismuth citrate or bismuth subcitrate (De-Nol) for 10 or 21 d and were orally challenged with 7 combined strains of C. jejuni (n = 6 birds/treatment). For both treatment groups, cecal Campylobacter colonization was reduced when birds were fed 200 ppm for 10 d but not 21 d. For the 50 ppm treatment group, only birds dosed with bismuth citrate for 21 d demonstrated any reduction in cecal Campylobacter concentrations when compared with controls. These data suggest that bismuth citrate and colloidal bismuth subcitrate may reduce cecal colonization by Campylobacter in broilers, but these effects are inconsistent.

Effect of oral administration of Butyrivibrio fibrisolvens MDT-1 on experimental enterocolitis in mice

Butyrivibrio fibrisolvens MDT-1, a butyrate-producing strain, was evaluated for use as a probiotic to prevent enterocolitis. Oral administration of the MDT-1 strain (10(9) CFU/dose) alleviated the symptoms of colitis (including body weight loss, diarrhea, bloody stool, organic disorder, and mucosal damage) that are induced in mice drinking water that contains 3.0% dextran sulfate sodium. In addition, myeloperoxidase (MPO) activity levels in colonic tissue were reduced, suggesting that MDT-1 mitigates bowel inflammation. The addition of MDT-1 culture supernatant inhibited the growth of nine clinical isolates of Campylobacter jejuni and Campylobacter coli that could potentially cause enterocolitis. Infection of mice with C. coli 11580-3, one of the isolates inhibited by MDT-1 in vitro, resulted in diarrhea, mucosal damage, increased MPO activity levels in colonic tissue, increased numbers of C. coli in the cecum, and decreased body weight gain. However, administration of MDT-1 to mice, prior to and during C. coli infection, reduced these effects. These results suggest that Campylobacter-induced enterocolitis can be alleviated by using B. fibrisolvens as a probiotic.

Campylobacter in primary animal production and control strategies to reduce the burden of human campylobacteriosis

Campylobacteriosis is one of the most important bacterial food-borne illnesses in humans. One significant source of infection is the handling and consumption of poultry meat, although other sources also contribute considerably. Controlling Campylobacter in broilers reduces the human burden of illness. Broilers can easily become colonised with Campylobacter and preventive measures in primary production have a limited and unpredictable effect. Vaccination, competitive exclusion, bacteriophage therapy and the use of bacteriocins are not yet commercially available. However, measures in the slaughterhouse can reduce contamination in the final product. At present, the most promising control strategy is to keep colonised and non-colonised flocks separate during slaughter ('scheduled processing'). The virtually Campylobacter-free meat can supply the fresh poultry meat market, while the meat from infected flocks can be treated to reduce the Campylobacter concentration. Meat from infected flocks can be treated by freezing but chemical decontamination appears to be more cost effective. A variant of this scenario is to treat only highly contaminated meat. The authors conclude that, until new techniques become commercially available, scheduled processing is the most cost-effective approach. Finally, the authors describe trends in antimicrobial resistance in Campylobacter.

Efficacy of Iron Chelators on Campylobacter Concentrations in Turkey Semen

Campylobacter is a leading bacterial cause of human foodborne infections in the United States. Recent studies suggest that the organism is highly prevalent in poultry semen and may contribute to vertical transmission between the breeder hen and offspring. Because Campylobacter requires iron for its growth and survival, the objective of this study was to determine if the addition of natural and synthetic chelators such as ovotransferrin, desferrioxaime, EDTA, or 2,2'-dipyridyl could reduce or eliminate Campylobacter in turkey semen. In a preliminary study without semen, a commercial poultry semen extender was supplemented with various concentrations of ovotransferrin, desferrioxaime, EDTA, or 2,2'-dipyridyl and inoculated with an average of 10(8) cfu/mL of a wild-type Campylobacter coli turkey semen isolate. At 6 and 24 h of storage at 4 degrees C, a sample was taken from each treatment group and enumerated for Campylobacter. In all 3 trials, Campylobacter was undetectable (< 10(2)) in the commercial poultry semen extender supplemented with 20 mg/mL of 2,2'-dipyridyl. There were no differences observed in Campylobacter concentrations in the commercial poultry semen extender supplemented with ovotransferrin, desferrioxaime, or EDTA compared with unsupplemented controls. In a follow-up study, pooled semen samples were randomly collected from toms, diluted with a commercial poultry semen extender supplemented with 5, 10, or 20 mg/mL of 2,2'-dipyridyl and inoculated with an average of 10(8) cfu/mL of a wild-type C. coli turkey semen isolate. At 6 and 24 h of storage at 4 degrees C, samples were taken from each treatment group, enumerated for Campylobacter, and evaluated for sperm viability. In all 3 trials, supplementing the commercial poultry semen extender with 20 mg/mL of 2,2'-dipyryidyl significantly reduced (3 to 4 logs) Campylobacter concentrations when compared with the positive controls. Sperm viability was also reduced with this treatment, and, therefore, the use of 2,2'-dipyridyl may not be a practical treatment for reducing Campylobacter in poultry semen.