Human Campylobacteriosis Research Articles

High rates of macrolide and fluoroquinolone resistance in human campylobacteriosis in the Middle East and North Africa.

Campylobacter is one of the main causative agents of bacterial gastrointestinal infections. Recently, a rise in the incidence of campylobacteriosis has been reported worldwide. Despite the clinical importance of this zoonotic disease, its microbiological diagnosis is not systematically performed in clinical laboratories in developing countries such as the Middle East and North Africa region. Multidrug-resistant Campylobacter isolates, particularly against erythromycin and ciprofloxacin, have been highly reported. The findings of this study highlight the critical need to urge clinical laboratories in the Middle East and North Africa region to include screening for Campylobacter in the routine stool culture of diarrheal patients. Although there is apaucity of data regarding the epidemiology of human campylobacteriosis, alarming rates of infection prevalence and antimicrobial resistance were found in Egypt, Iran, Qatar and Lebanon.

The temporal pattern and relationship of Campylobacter prevalence in broiler slaughter batches and human campylobacteriosis cases in Sweden 2009–2019

Thermophilic Campylobacter species are the most common cause of bacterial gastroenteritis worldwide, and handling and consumption of broiler meat is considered a major foodborne transmission route. Both the incidence of campylobacteriosis and the prevalence of Campylobacter in broilers show seasonality but the impact of this association and broiler prevalence on human incidence is not clear. To explore this relationship we applied two approaches for analyzing time series data using different time resolutions (weekly, bi-weekly or monthly data) of human campylobacteriosis cases and prevalence of Campylobacter spp. in broiler slaughter batches in Sweden between 2009 and 2019. The decomposition of time series into seasonal (S), long-term trend (T) and residual components (STL model) showed a close overlap in seasonal patterns in terms of timing and the proportional change of peaks from normalized yearly levels. Starting 2016, when a large outbreak was reported, there was significant overlap in the trend components as well. The trend component of human cases prior to the outbreak corresponded to a linear increase of 6.5 % cases annually. In comparison, the estimated annual increase in broiler consumption was 2.7 %. An additive approach for time-series counts incorporating seasonal and epidemic (cases are a function of previous cases) components found a positive association between human cases and broiler prevalence with an optimal lag of 2 weeks, 1 bi-week, or 0 months. Considering the estimated time between slaughter and consumption, incubation time, and the time between on-set of disease and testing, a 2-week lag may be consistent with transmission via handling and consumption of fresh broiler meat. The best model included broiler prevalence as a factor in the epidemic model component, not in the seasonal component. The outcomes in terms of best model, optimal lags and significance of parameters, using weekly, bi-weekly or monthly data were, in general, in agreement but varied with data resolution when only a subset of the time series, not including any known broiler associated outbreaks, was analyzed. The optimal resolution based on the available data and conditions of the present analysis appeared to be weekly or bi-weekly data. Results suggest that broiler prevalence with a 2 week lag period can explain part of the human cases but has a smaller explanatory impact during the part of the study period not including the large known outbreaks. There is no simple relationship between broiler prevalence and human cases. Additional factors than broiler prevalence need to be evaluated in order to understand the transmission routes and epidemiology of campylobacteriosis.

Differences in the Propensity of Different Antimicrobial Resistance Determinants to Be Disseminated via Transformation in Campylobacter jejuni and Campylobacter coli.

Campylobacter jejuni and Campylobacter coli are leading zoonotic foodborne pathogens, and the drugs of choice for human campylobacteriosis are macrolides (e.g., erythromycin) and fluoroquinolones. C. jejuni and C. coli are naturally competent for transformation via naked DNA uptake, but potential differences in transformation frequency (TF) for different antimicrobial resistance (AMR) markers remain poorly understood. We determined TFs for resistance to different antibiotics using as recipient a derivative of C. jejuni NCTC 11168 (strain SN:CM) with donor DNA from multidrug-resistant C. jejuni or C. coli. TF for nalidixic acid resistance ranked significantly highest (~1.4 × 10−3), followed by resistance to streptomycin and gentamicin. Tetracycline resistance via chromosomal tet(O) was less commonly transferred (~7.6 × 10−7), while transformation to erythromycin resistance was rare (≤4.7 × 10−8). We also determined TFs with the contemporary poultry-derived strains C. jejuni FSIS 11810577 and C. coli FSIS 1710488 as recipients. TFs to nalidixic acid and streptomycin resistance remained the highest (~7 × 10−4). However, TF for gentamicin resistance was remarkably low in certain recipient–donor combinations, while average TF for erythromycin resistance was noticeably higher (~3 × 10−6) than with SN:CM. Findings from this experimental model provide insights into factors that may impact transformation-mediated transfer of AMR leading to AMR dissemination in the agricultural ecosystem.

Research Note: Effect of a phlorotannin extract of the brown seaweed Ascophyllum nodosum as a potential control strategy against Campylobacter in broilers

Poultry is generally recognized as the main source of human campylobacteriosis and Campylobacter is highly prevalent at the farm level. To reduce the relative risk of human campylobacteriosis attributable to broiler meat, it is necessary to reduce Campylobacter loads in broiler ceca but to date, no effective, reliable and practical strategy is available. The marine environment is a rich source of original natural compounds exhibiting different biological activities. The objective of this study was to test a phlorotannin extract of the brown seaweed Ascophyllum nodosum as a potential control strategy against Campylobacter in broilers. Bactericidal activity has been demonstrated in vitro, on several Campylobacter spp. strains at a range of 0.06 to 0.47 mg/mL. Therefore, an in vivo trial in experimental facilities was performed to evaluate addition of 0.2% (w/w) of an A. nodosum extract to feed distributed at the end of rearing from day 31 to day 35, and to assess the effect on artificial Campylobacter jejuni colonization. No statistical differences in Campylobacter enumeration were observed between the treated and control groups. Another trial was performed in a commercial broiler flock. Feed containing the extract at 0.2% (w/w) (2 kg/t) was distributed during the last 5 days of rearing (day 33–day 38). No significant effects on Campylobacter colonization and on growth parameters were observed compared to the control group. Additional studies are needed to assess whether active polyphenols are found in the cecum.

Source Attribution of Human Campylobacteriosis Using Whole-Genome Sequencing Data and Network Analysis.

Campylobacter spp. are a leading and increasing cause of gastrointestinal infections worldwide. Source attribution, which apportions human infection cases to different animal species and food reservoirs, has been instrumental in control- and evidence-based intervention efforts. The rapid increase in whole-genome sequencing data provides an opportunity for higher-resolution source attribution models. Important challenges, including the high dimension and complex structure of WGS data, have inspired concerted research efforts to develop new models. We propose network analysis models as an accurate, high-resolution source attribution approach for the sources of human campylobacteriosis. A weighted network analysis approach was used in this study for source attribution comparing different WGS data inputs. The compared model inputs consisted of cgMLST and wgMLST distance matrices from 717 human and 717 animal isolates from cattle, chickens, dogs, ducks, pigs and turkeys. SNP distance matrices from 720 human and 720 animal isolates were also used. The data were collected from 2015 to 2017 in Denmark, with the animal sources consisting of domestic and imports from 7 European countries. Clusters consisted of network nodes representing respective genomes and links representing distances between genomes. Based on the results, animal sources were the main driving factor for cluster formation, followed by type of species and sampling year. The coherence source clustering (CSC) values based on animal sources were , and for cgMLST, wgMLST and SNP, respectively. The CSC values based on Campylobacter species were , and for cgMLST, wgMLST and SNP, respectively. Including human isolates in the network resulted in , and of the total human isolates being clustered with the different animal sources for cgMLST, wgMLST and SNP, respectively. Between and of human isolates were not attributed to any animal source. Most of the human genomes were attributed to chickens from Denmark, with an average attribution percentage of , and for cgMLST, wgMLST and SNP distance matrices respectively, while ducks from Denmark showed the least attribution of for all three distance matrices. The best-performing model was the one using wgMLST distance matrix as input data, which had a CSC value of . Results from our study show that the weighted network-based approach for source attribution is reliable and can be used as an alternative method for source attribution considering the high performance of the model. The model is also robust across the different Campylobacter species, animal sources and WGS data types used as input.

Dairy Cattle Density and Temporal Patterns of Human Campylobacteriosis and Cryptosporidiosis in New Zealand

Public health risks associated with the intensification of dairy farming are an emerging concern. Dairy cattle are a reservoir for a number of pathogens that can cause human illness. This study examined the spatial distribution of dairy cattle density and explored temporal patterns of human campylobacteriosis and cryptosporidiosis notifications in New Zealand from 1997 to 2015. Maps of dairy cattle density were produced, and temporal patterns of disease rates were assessed for urban versus rural areas and for areas with different dairy cattle densities using descriptive temporal analyses. Campylobacteriosis and cryptosporidiosis rates displayed strong seasonal patterns, with highest rates in spring in rural areas and, for campylobacteriosis, summer in urban areas. Increases in rural cases often preceded increases in urban cases. Furthermore, disease rates in areas with higher dairy cattle densities tended to peak before areas with low densities or no dairy cattle. Infected dairy calves may be a direct or indirect source of campylobacteriosis or cryptosporidiosis infection in humans through environmental or occupational exposure routes, including contact with animals or feces, recreational contact with contaminated waterways, and consumption of untreated drinking water. These results have public health implications for populations living, working, or recreating in proximity to dairy farms.

Prevalence and antimicrobial susceptibility pattern of Campylobacter jejuni in raw retail chicken meat in Metropolitan Accra, Ghana

Although, Campylobacter spp. are a major cause of foodborne gastroenteritis, its occurrence and antimicrobial resistance traits have not been well defined in low income countries, particularly in Africa. In this study, retail chicken was sampled (n = 400) between February 2019 to January 2020 in Metropolitan Accra, Ghana, to determine the prevalence and antimicrobial susceptibility pattern of Campylobacter jejuni. Raw chicken samples were obtained in wet markets (n = 315) and supermarkets (n = 85) and each subjected to direct plating and broth enrichment according to standard culture methods for Campylobacter spp. with the identity of presumptive positive colonies confirmed by MALDI-TOF. The susceptibility of isolates to antibiotics commonly used for campylobacteriosis in humans (in order to reflect the One Health significance of Campylobacter at the human-food interface) were then assessed by disc diffusion. A prevalence of 38.3% was recorded and all isolates were confirmed as Campylobacter jejuni. Enrichment yielded 127 positives while direct plating yielded 55 positives with low level of agreement in detection between these assays (Kappa = 0.15). Among samples positive by direct plating, the mean Campylobacter count was 1.9 log10 CFU/g (sd ±0.8). About 13% (7/55) of the samples positive by direct plating contained counts of 3log and above. Samples from the wet market yielded more positives than those from the supermarket with the rate of isolation from wet markets being 1.6 times that of the supermarket. Among 182 isolates characterized for their antimicrobial susceptibility, resistance to fluoroquinolones was 99.5%, tetracyclines 100% and macrolides 26.9%. Multi-drug resistance was also observed in 26.9% of the screened isolates. The findings point to a potential high level of exposure of humans to Campylobacter jejuni through chicken meat and thus the need for education on hygienic preparation and handling of raw chicken. High rates of resistance to classes of antimicrobials critically important for treating Campylobacter infections in humans; fluroquinolones and macrolides, affirm the need for stronger regulatory control of antimicrobials and enhanced antimicrobial stewardship in chicken production.

Live-Attenuated Oral Vaccines to Reduce Campylobacter Colonization in Poultry.

The control of Campylobacter in poultry at the pre-harvest level is critical to reducing foodborne infections with Campylobacter since the consumption of contaminated poultry is the most frequent cause of human campylobacteriosis. Although poultry vaccination is suggested as useful intervention measures, no Campylobacter vaccines are currently available. To develop live-attenuated oral Campylobacter vaccines, in this study, we evaluated the efficacy of pre-colonization by oxidative stress defense mutants, including knockout mutants of ahpC, katA, and sodB, in preventing Campylobacter jejuni from colonizing poultry. Interestingly, when chickens were pre-colonized with ΔahpC and ΔkatA mutants, rather than the ΔsodB mutant, the level of C. jejuni colonization was significantly reduced within 35 days. Further studies demonstrated when chickens were pre-colonized with the ΔahpC mutant by oral challenge with a high dose (ca., 5 × 108 CFU/bird) and a low dose (ca., 5 × 106 CFU/bird), it twice reduced the level of C. jejuni by 3.9 log10CFU/g feces and 3 log10CFU/g feces after 42 days, respectively, compared to the untreated control. Due to a colonization defect, the ΔahpC mutant was removed from chickens within 42 days. After excretion from the host, moreover, the ΔahpC mutant cannot survive in aerobic environments because of compromised aerotolerance. Our findings suggest that the ahpC mutant has a great potential for on-farm application to control C. jejuni at the pre-harvest level.

Campylobacter Species in the Middle East

Campylobacter is a contributing factor in many pathogen conditions. The present study aimed to review the previous findings of studies on campylobacteriosis in the Middle East region. Acute gastroenteritis is caused by Campylobacter species, known as a widespread infectious disease with worldwide disbursement. There are various reports on the incidence of Campylobacter in the Middle East indicating the infection rates of 1-14%. Campylobacter jejuni (C. jejuni) and C. coli are the main responsible campylobacteriosis for intestinal diseases. The occurrence of human campylobacteriosis is sporadic, transmission from one person to another person is too rare and the incidence is usually higher in warm seasons and tropical environments. The presence of Campylobacter species as normal flora in stool and its contamination in poultry meat and eggs can lead to infections. Lowering the number of Campylobacter in animal carcasses can greatly decrease the risk of infection in consumers. Due to the high Campylobacter spp. antibiotic resistance, the governments are required to devise controlling programs. People in the Middle East should buy meat from stores that are under sanitary monitoring.

Prevalence of antimicrobial resistance in Campylobacter spp.: A review of the literature.

Campylobacter spp. are commensal organisms in the intestinal tract of food producing and companion animals. There is an increasing trend of human campylobacteriosis worldwide, including complicated cases that request treatment by antibiotics. Prevalence of resistance continually increases, especially to fluoroquinolones and tetracyclines. There are many reports on multiresistant strains of Campylobacter spp.In this work we present the available information about the prevalence and antimicrobial resistance of Campylobacter spp. worldwide, as well as studies from Serbia published in last two decades. Campylobacter strains isolated from animal samples in Serbia showed increased prevalence of antimicrobial resistance to all clinically relevant antibiotics. Preliminary data (2014-2019) from Reference laboratory for Campylobacter and Helicobacter at the Institute of Public Health of Niš, Serbia show high resistance rates to ciprofloxacin (90%) and to tetracycline (50%) but low resistance to erythromycin (<5%) in human Campylobacter isolates.

Human Campylobacteriosis in Southeast Asia: A Meta-Analysis and Systematic Review

Human Campylobacteriosis in Southeast Asia: A Meta-Analysis and Systematic Review

Campylobacter jejuni Virulence Factors Identified by Modulating Their Synthesis on Ribosomes With Altered rRNA Methylation.

Campylobacter jejuni is a major cause of food poisoning worldwide, and remains the main infective agent in gastroenteritis and related intestinal disorders in Europe and the USA. As with all bacterial infections, the stages of adhesion to host tissue, survival in the host and eliciting disease all require the synthesis of proteinaceous virulence factors on the ribosomes of the pathogen. Here, we describe how C. jejuni virulence is attenuated by altering the methylation of its ribosomes to disrupt the composition of its proteome, and how this in turn provides a means of identifying factors that are essential for infection and pathogenesis. Specifically, inactivation of the C. jejuni Cj0588/TlyA methyltransferase prevents methylation of nucleotide C1920 in the 23S rRNA of its ribosomes and reduces the pathogen’s ability to form biofilms, to attach, invade and survive in host cells, and to provoke the innate immune response. Mass spectrometric analyses of C. jejuni TlyA-minus strains revealed an array of subtle changes in the proteome composition. These included reduced amounts of the cytolethal distending toxin (CdtC) and the MlaEFD proteins connected with outer membrane vesicle (OMV) production. Inactivation of the cdtC and mlaEFD genes confirmed the importance of their encoded proteins in establishing infection. Collectively, the data identify a subset of genes required for the onset of human campylobacteriosis, and serve as a proof of principle for use of this approach in detecting proteins involved in bacterial pathogenesis.

The prevalence, counts, and MLST genotypes of Campylobacter in poultry meat and genomic comparison with clinical isolates

Since 2005 campylobacteriosis has been the most commonly reported gastrointestinal infection in humans in the European Union with more than 200,000 cases annually. Also Campylobacter is one of the most frequent cause of food-borne outbreaks with 319 outbreaks reported to EFSA, involving 1,254 cases of disease and 125 hospitalizations in EU in 2019. Importantly poultry meat is one of the most common source for the sporadic Campylobacter infections and for strong-evidence campylobacteriosis food-borne outbreaks in EU. In present study, 429 fresh broiler chicken meat samples of Estonian, Latvian, and Lithuanian origin were collected from Estonian retail level and analyzed on a monthly basis between September 2018 and October 2019. Campylobacter spp. were isolated in 141 (32.9%) of 429 broiler chicken meat samples. Altogether 3 (1.8%), 49 (36.8%), and 89 (66.9%) of Estonian, Latvian, and Lithuanian origin broiler chicken meat samples were positive for Campylobacter spp. Among Campylobacter-positive samples, 62 (14.5%) contained Campylobacter spp. below 100 CFU/g and in 28 (6.5%) samples the count of Campylobacter spp. exceeded 1,000 CFU/g. A high prevalence of Campylobacter spp. in fresh broiler chicken meat of Lithuanian and Latvian origin in Estonian retail was observed. Additionally, 22 different multilocus sequence types were identified among 55 genotyped isolates of broiler chicken meat and human origin, of which 45 were Campylobacter jejuni (C. jejuni) and 10 were Campylobacter coli (C. coli). The most prevalent multilocus sequence types among C. jejuni was ST2229 and among C. coli ST832, ST872. C. jejuni genotypes found in both broiler chicken meat and human origin samples were ST122, ST464, ST7355, and ST9882, which indicates that imported fresh broiler chicken meat is likely the cause of human campylobacteriosis in Estonia.

In vitro and in vivo evaluation of probiotic as immunomodulatory and anti-Campylobacter agent

Human campylobacteriosis can be transmitted from animals to human either directly or through contaminated food. So, food safety plays a critical role in preventing the prevalence of food-borne diseases. Probiotics microorganisms are considered one of the most promising new strategies in controlling gastrointestinal tract (GIT) infection. In this study, two probiotic strains Lactobacillus delbrueckii subsp. bulgaricus DSM 20080 and Bifidobacterium bifidum were investigated as anti-Campylobacter agent both in vitro and in vivo. Where they showed elevated antibacterial activity when used as mixed culture with a significant downregulation in the mice intestinal gene expression of IL-1β mRNA and TNF-α mRNA induced by Campylobacter jejuni. Besides, the histopathological investigation of mice intestinal tissue showed great morphological changes in the infected groups with C. jejuni compared with Probiotics treated group that showed healthy intestinal sections with well-defined and enhanced villi. Generally, our findings demonstrate that probiotics have a beneficial and significant effect in the reduction and treatment of destructive effect of C. jejuni on mice gut.

Virulence, MLST analysis, and antimicrobial resistance of Campylobacter coli isolated from broiler chickens in Tamil Nadu, India.

Campylobacter species are the zoonotic bacteria and the most common cause of foodborne gastroenteritis around the world. The link between human campylobacteriosis and infected poultry consumption has been well established. In this study, we aimed to isolate Campylobacter spp. from chicken and characterize them with molecular methods. Totally, 241 chicken caecal mucosal scrapings were collected from five districts of Tamil Nadu. Bacterial isolation was done by plating on blood-free Campylobacter selective medium with supplements. Campylobacter species were identified by multiplex PCR and Campylobacter coli isolates were tested for 11 virulence genes by PCR. C. coli isolates were typed based on seven housekeeping genes multilocus sequence typing (MLST) scheme. The antimicrobial susceptibility was determined by a microdilution resazurin assay. The prevalence of C. coli and C. jejuni were 14.94% (36/241), and 3.32% (8/241), respectively. The virulence genes flaA, flaB, cadF, cdtA, cdtB, cdtC, ciaB, and ceuE were present in all 36 C. coli isolates, pldA and racR genes were present in 58.33% (21/36), and 16.67% (6/36) of the isolates, respectively, and dnaJ was present in only one isolate. Two novel sequence types (ST-10872, ST-11031) were found in this study. Though different STs were identified, all the STs belonged to the same clonal complex of ST-828. All 14 C. coli isolates showed 100% resistance to nalidixic acid, and higher resistance to tetracycline (92.8%), erythromycin (71.4%), clindamycin (71.4%), and azithromycin (64.2%) was noticed. All C. coli isolates were sensitive to chloramphenicol, and higher sensitivity to ciprofloxacin (78.5%), and gentamicin (71.4%) was observed. The present study demonstrated that C. coli is more prevalent in broilers than C. jejuni in Tamil Nadu. The presence of C. jejuni and C. coli in chicken caecal samples from the slaughterhouse are indicative of the possibility of public health hazards.

Prevalence and risk factors of Campylobacter species infection of puppies in the Nairobi Metropolitan Region, Kenya

Campylobacter species are bacterial pathogens of veterinary and public health significance. Despite the fact that several studies have identified close contact with puppies as a risk factor for human campylobacteriosis, the current status of Campylobacter species infecting puppies in Kenya is unclear. The purpose of this study was to determine the prevalence of Campylobacter species infection of puppies and the associated risk factors in the Nairobi Metropolitan Region, Kenya. A cross-sectional study was carried out from January 2021 to August 2021. Rectal swabs from 260 puppies were collected aseptically, and Campylobacter species were isolated and identified using conventional culture techniques and biochemical tests. To collect information on potential risk factors, a questionnaire survey was given to owners at the facilities where the rectal swab samples were taken. Variables were identified as risk factors for Campylobacter species colonization using univariable and multivariable mixed effects logistic regression analyses. Campylobacter species were isolated from 150 of the 260 sampled puppies yielding a prevalence of 57.7%. This study shows that Campylobacter species are present in Kenyan puppies. The reasons for keeping puppies, deworming status of puppies, and puppies with a recent history of vomiting had significant association with Campylobacter species colonization in puppies. Being a household puppy, being more than 2 months of age, being kept for security as well as having an ideal body condition or being moderately obese were identified as protective factors. Understanding the risk factors for Campylobacter species carriage in puppies will aid in the development of awareness and management strategies to improve puppy health and welfare while potentially lowering the risk of this pathogen being transmitted from puppies to humans.

Characterisation of burden of illness measures associated with human (Fluoro)quinolone-resistant Campylobacter spp. infections - a scoping review.

Campylobacter spp. are one of the most common causes of bacterial gastroenteritis in Canada and worldwide. Fluoroquinolones are often used to treat complicated human campylobacteriosis and strains of Campylobacter spp. resistant to these drugs are emerging along the food chain. A scoping review was conducted to summarise how human (fluoro)quinolone-resistant (FQR; quinolones including fluoroquinolones) Campylobacter spp. infections are characterised in the literature by describing how burden of illness (BOI) associated with FQR is measured and reported, describing the variability in reporting of study characteristics, and providing a narrative review of literature that compare BOI measures of FQR Campylobacter spp. infections to those with susceptible infections. The review identified 26 studies that yielded many case reports, a lack of recent literature and a lack of Canadian data. Studies reported 26 different BOI measures and the most common were hospitalisation, diarrhoea, fever and duration of illness. There were mixed results as BOI measures reported in literature were inconsistently defined and there were limited comparisons between resistant and susceptible infections. This presents a challenge when attempting to assess the magnitude of the BOI due to FQR Campylobacter spp., highlighting the need for more research in this area.

Campylobacter spp. prevalence and fluoroquinolone resistance in chicken layer farms.

Chicken is a major source of human campylobacteriosis. Chicken meat originates not only from broilers but also from spent layers; however, few reports have documented the prevalence and antimicrobial resistance of Campylobacter spp. in layers in Japan. Therefore, we investigated the prevalence and antimicrobial susceptibility of Campylobacter spp. in 47 layer farms in Japan. Fecal samples were collected from the youngest and oldest flocks on the farm, and Campylobacter spp. was isolated from 46/47 (97.9%) farms. Among the C. jejuni isolates, the resistance rates to ampicillin, tetracycline, and ciprofloxacin were 29.6%, 22.2%, and 19.8%, respectively. The ciprofloxacin resistance rate (7.3%) in C. jejuni isolated from old flocks was significantly (P<0.01) lower than that in young flocks (32.5%).

Isolation and Characterization of Group III Campylobacter jejuni-Specific Bacteriophages From Germany and Their Suitability for Use in Food Production.

Campylobacter spp. are a major cause of bacterial foodborne diarrhea worldwide. While thermophilic Campylobacter species asymptomatically colonize the intestines of chickens, most human infections in industrial countries have been attributed to consumption of chicken meat or cross-contaminated products. Bacteriophages (phages) are natural predators of bacteria and their use at different stages of the food production chain has been shown to reduce the public health burden of human campylobacteriosis. However, regarding regulatory issues, the use of lytic phages in food is still under discussion and evaluation. This study aims to identify lytic phages suitable for reducing Campylobacter bacteria along the food production chain. Therefore, four of 19 recently recovered phages were further characterized in detail for their lytic efficacy against different Campylobacter field strains and their suitability under food production settings at different temperatures and pH values. Based on the results of this study, the phages vB_CjM-LmqsCP1-4 and vB_CjM-LmqsCP1-5 appear to be promising candidates for the reduction of Campylobacter jejuni in food production settings.

An updated assessment of the effect of control options to reduce Campylobacter concentrations in broiler caeca on human health risk in the European Union

Quantitative microbiological risk assessment (QMRA) studies have suggested that control options to reduce the concentration of Campylobacter spp. in broiler chicken caeca may be highly effective at reducing the risk of human campylobacteriosis. These QMRA studies have been updated based on scientific evidence obtained in the past decade. The relationship between Campylobacter concentrations in the caeca and on broiler skins after industrial processing was modelled by means of linear regression and combined with a number of consumer phase models (CPM) and dose-response (DR) models. The reduction of caecal Campylobacter concentration as reported for selected feed additives and vaccines, was used to estimate the relative risk reduction expressed as the percentage decrease in human campylobacteriosis cases in the EU associated with consumption of broiler meat. The model outputs suggest that the effectiveness of these control options are less pronounced than previously indicated. For example, the median estimate for the relative risk reduction obtained through a 2 log10 reduction in caecal concentrations was 39% (95% CI 9–73%), whereas previous estimates were between 76 and 98%. The main reason for this finding is that recent studies show lower values for the slope of the regression line; the impact of using newly published DR models and CPMs is smaller. Still, the uncertainty associated to the estimated effects is large, mainly due to uncertainty about the slope of the regression line. Additionally, data on the effectiveness of vaccination and the application of feed and water additives obtained under field conditions are scarce, but they are a prerequisite to assess the risk reduction that may be achieved by these control options when applied in practice.