Occurrence of thermotolerant Campylobacter species in surface waters of a Mediterranean area and in its prevailing pollution sources

Aims: To determine the prevalence of Campylobacter in surface waters of a highly populated Mediterranean area. Methods and Results: Surface water and wastewater samples were collected from an area in the north‐east of Spain during a 2‐year study. All the samples were analysed using the MPN method and Multiplex PCR to quantify and identify Campylobacter. It was detected in 82% of the samples from the Llobregat River with a mean of 1·3 MPN 100 ml^?1. The lowest counts were obtained in summer. Campylobacter coli was the predominant species in this river. The bacteria were isolated from marsh water but not from seawater samples. The highest counts of campylobacters were found in poultry wastewater where Camp. jejuni was the predominant species, as in urban sewage. In pig slurry, Camp. coli was the only species detected. Conclusions: Campylobacter jejuni and Camp. coli are present and widely distributed in the surface water of the studied area. The two species co‐exist, with Camp. coli being predominant. In river water, campylobacter counts presented a seasonal distribution. No relationship with faecal indicators was found. Significance and Impact of the Study: This study provides the first data on the occurrence and concentrations of thermotolerant campylobacter species in surface water in a Mediterranean area.     

Detection of Campylobacter jejuni and Camp. coli in chicken faecal samples by PCR

H.N. RASMUSSEN, J.E. OLSEN, K. JØRGENSEN AND O.F. RASMUSSEN. 1996. PCR primers were selected from the flagellin gene sequences flaA and flaB of Campylobacter coli to amplify DNA from Camp. jejuni and Camp. coli. When the PCR products were analysed by hybridization to an internal probe immobilized in microtitre wells, positive reactions were observed only for strains of Camp. jejuni and Camp. coli. The assay was used to analyse 31 chicken faecal samples. Full correspondence was found between the PCR assay conducted on the enriched cultures and the standard culture method. When analysing the transport medium prior to enrichment, the PCR assay detected nine of 11 culture positive samples.     

The effects of UVB and temperature on the survival of natural populations and pure cultures of Campylobacter jejuni, Camp. coli, Camp. lari and urease-positive thermophilic campylobacters (UPTC) in surface waters

AIMS: To determine whether diurnal and seasonal variations in campylobacters in surface waters result from the effects of temperature and u.v. radiation, and whether natural populations of Campylobacter lari and urease-positive thermophilic campylobacters (UPTC) from birds survive better in surface waters than Camp. jejuni from sewage. METHODS AND RESULTS: Natural populations of Camp. lari and UPTC in sea water, and Camp. jejuni in river water, were exposed to artificial sunlight (equivalent to a sunny day in June). Both populations became non-culturable within 30 min, with T90s of 15 min and 25 min, respectively. Cultures of Camp. jejuni became non-culturable within 40 min and those of Camp. coli, Camp. lari and UPTC, within 60 min. In darkness, survival was temperature-dependent. Natural populations took 12 h at 37 degrees C and 5 days at 4 degrees C to become non-culturable in sea water, and slightly less in river water. Cultures of Camp. lari and UPTCs survived for significantly longer than Camp. jejuni and Camp. coli. Loss of culturability for all isolates was most rapid at 37 degrees C and slowest at 4 degrees C. Newly isolated strains from sea water and river water behaved in an almost identical manner to NCTC strains. CONCLUSION: Campylobacter lari and UPTCs survive for longer in surface waters than Camp. jejuni and Camp. coli, particularly in the dark. Low Campylobacter numbers in coastal waters in the summer, especially in the afternoon, are due to the combined effects of higher temperatures and higher levels of u.v. radiation. SIGNIFICANCE AND IMPACT OF THE STUDY: Campylobacter lari and UPTCs from birds predominate in bathing waters in Morecambe Bay because they are better able to survive; they also originate from closer to the shore than Camp. jejuni and Camp. coli in sewage effluent, which survive poorly and die before the incoming tide reaches the shore. The predominance of Camp. jejuni in river water results from its dominance of the inputs and not from its ability to survive.     

Campylobacter in chicken livers and their destruction by pan frying

AIM: To enumerate Campylobacter spp. on the external surface and internal portions of chicken livers, and to assess the cooking required to inactivate naturally present cells. METHODS AND RESULTS: Of 30 livers tested all yielded Campylobacter spp. on their surfaces and 90% were found to contain the organism in internal tissue. Four (13%) livers contained >10(4) MPN campylobacters, and an additional seven (23%) contained >10(3) MPN campylobacters per liver. The internal temperature of pan-fried livers under the conditions used reached a maximum of 70-80 degrees C, and maintaining this temperature for 2-3 min was necessary to inactivate naturally occurring Campylobacter spp. All isolates identified were either C. jejuni or C. coli. CONCLUSIONS: Chicken livers represent a potential source of human campylobacteriosis as they contained >10(4) MPN per liver in 13% of the samples tested. Pan-frying can produce an acceptable product that is safe to eat. SIGNIFICANCE AND IMPACT OF THIS STUDY: The data provided can be used in exposure assessments of Campylobacter in poultry products in terms of both quantitative data and assessing pan-frying and its ability to destroy campylobacters.     

The incidence of Campylobacter spp. on processed turkey from processing plants in the midwestern United States

AIM: The primary aim of this study was to determine the incidence of Campylobacter spp. on turkey, presented for processing at participating production plants located in the midwest region of the United States. METHODS AND RESULTS: The two participating plants were visited on a monthly basis for a period of 1 year. Sampling of carcasses was carried out using a surface swab technique. Swabs were obtained from carcasses at two points on the production line - prechill and postchill. In addition, samples of chill water were also obtained for examination. Isolation and detection of Campylobacter was carried out using enrichment in Preston broth with recovery of the organism on blood free Campylobacter selective agar (CCDA). Isolates recovered were screened and identified using the API Campy identification system. The study found that 34.9% of all samples tested were positive for Campylobacter spp. The overall, contamination rates observed for both plants were relatively similar (39.2% for plant A and 30.6% for plant B). Differences were observed in the incidence of Campylobacter spp. on prechill vs postchill carcasses (i.e. 40.8% prechill vs 37.6% postchill for plant A and 41.8% prechill vs 19.8% postchill for plant B). Campylobacter species most often isolated included Camp. jejuni and Camp. coli. Other species recovered were Camp. fetus fetus, Camp. upsaliensis and Camp. lari. CONCLUSIONS: The incidence of Campylobacter spp. on processed poultry was relatively common. Factors such as the processing plant examined, season and the farms presenting birds for processing influenced the incidence of the pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY: Differences were observed in the prevalence of Campylobacter spp. isolated from the two plants examined. The study suggests a seasonal prevalence of Campylobacter in the cooler months with processing conditions also influencing the overall occurrence of the organism. The incidence, isolation and detection of Campylobacter spp. from processed poultry are discussed.     

Prevalence, quantification and typing of adenoviruses detected in river and treated drinking water in South Africa

AIMS: Human adenoviruses (HAds), of which there are 51 serotypes, are associated with gastrointestinal, respiratory, urinary tract and eye infections. The importance of water in the transmission of HAds and the potential health risks constituted by HAds in these environments are widely recognized. Adenoviruses have not previously been quantified in river and treated drinking water samples. In this study, HAds in river water and treated drinking water sources in South Africa were detected, quantified and typed. METHODS AND RESULTS: Adenoviruses were recovered from the water samples using a glass wool adsorption-elution method followed by polyethylene glycol/NaCl precipitation for secondary concentration. The sensitivity and specificity of two nested PCR methods were compared for detection of HAds in the water samples. Over a 1-year period (June 2002 to July 2003), HAds were detected in 5.32% (10/188) of the treated drinking water and 22.22% (10/45) of river water samples using the conventional nested PCR method. The HAds detected in the water samples were quantified using a real-time PCR method. The original treated drinking water and river water samples had an estimate of less than one copy per litre of HAd DNA present. The hexon-PCR products used for typing HAds were directly sequenced or cloned into plasmids before sequencing. In treated drinking water samples, species D HAds predominated. In addition, adenovirus serotypes 2, 40 and 41 were each detected in three different treated drinking water samples. Most (70%) of the HAds detected in river water samples analysed were enteric HAds (serotypes 40 and 41). One HAd serotype 2 and two species D HAds were detected in the river water. CONCLUSIONS: Adenoviruses detected in river and treated drinking water samples were successfully quantified and typed. The detection of HAds in drinking water supplies treated and disinfected by internationally recommended methods, and which conform to quality limits for indicator bacteria, warrants an investigation of the risk of infection constituted by these viruses. The risk of infection may have implications for the management of drinking water quality. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is unique as it is the first report on the quantification and typing of HAds in treated drinking water and river water. This baseline data is necessary for the meaningful assessment of the potential risk of infection constituted by these viruses.     

Identification of campylobacteria isolated from Danish broilers by phenotypic tests and species-specific PCR assays

AIMS: To validate a phenotypic Campylobacter species identification method employed to identify campylobacters in broilers by comparison with campylobacterial species identification using various species-specific PCR analyses. METHODS AND RESULTS: From a collection of 2733 phenotypically identified campylobacterial cultures, 108 Campylobacter jejuni cultures and 351 campylobacterial cultures other than Camp. jejuni were subjected to various species-specific PCR assays. On the basis of the genotypic tests, it was demonstrated that Camp. jejuni and Camp. coli constituted approx. 99% of all cultures, while other species identified were Helicobacter pullorum, Camp. lari and Camp. upsaliensis. However, 29% of the 309 Camp. coli cultures identified by phenotypic tests were hippurate-variable or negative Camp. jejuni cultures, whereas some Camp. lari cultures and unspeciated campylobacter cultures belonged to H. pullorum. It was also notable that 2-6% of the cultures were, in fact, mixed cultures. CONCLUSIONS: The phenotypic identification scheme employed failed to appropriately differentiate Campylobacter species and particularly to identify the closely related species, H. pullorum. SIGNIFICANCE AND IMPACT OF THE STUDY: Future phenotypic test schemes should be designed to allow a more accurate differentiation of Campylobacter and related species. Preferably, the phenotypic tests should be supplemented with a genotypic strategy to disclose the true campylobacterial species diversity in broilers.     

Use of a commercial gene probe assay kit for rapid MPN enumeration of Escherichia coli in drinking water

A commercial gene probe assay kit for presence/absence determination of Escherichia coli in food samples has been used in the standard UK six tube format most probable number (MPN) method for enumerating E. coli in drinking water samples. Presence/absence analysis with the gene probe kit (requiring 3 h) of all MPN tubes after a 21–24 h incubation (minerals modified glutamate; 37°C) enumerated confirmed E. coli in 24–27 h which offered an improvement of up to 48 h over the standard UK MPN method. MPNs determined by the gene probe method and the standard UK method agreed in nine of the 16 water samples which were analysed and for which E. coli concentrations were within the detection limits of the six tube MPN format. This was consistent with the gene probe method detecting one E. coli in a tube. For the other seven water samples, the gene probe method registered positive only 20 of the 30 tubes which the standard UK method determined to be positive. The sensitivity of the gene probe method for drinking water samples, although encouraging, needs improvement perhaps through kit quality control procedures.     

Identification of thermophilic Campylobacter spp. by phenotypic and molecular methods

AIMS: The differences between phenotyping and genotyping (polymerase chain reaction- restriction fragment length polymorphism) of Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis were assessed. METHODS AND RESULTS: A total of 51, 63 and 88 strains from dogs, pigs and humans, respectively, were examined. The strains were first typed by biochemical methods, then by PCR-RFLP using AluI and Tsp509I. None of the strains were typed as Camp. lari by the PCR-RFLP. The biggest differences were found in the identification of Camp. jejuni and Camp. coli. The main discrepancies were caused with the hippurate hydrolysis test and sensitivity to cephalothin and nalidixic acid. Strains which were identified biochemically as Camp. coli and by digestion with AluI as Camp. jejuni (eight strains) were tested for the presence of the hippuricase gene. CONCLUSION: The PCR typing results showed the presence of the hippuricase gene as unique to Camp. jejuni. SIGNIFICANCE AND IMPACT OF THE STUDY: A reliable identification of Campylobacter spp. should be supplemented with a molecular method.     

The occurrence of Campylobacter in river water and waterfowl within a watershed in southern Ontario,Canada

Aims: Quantitative PCR and a culture method were used to investigate Campylobacter occurrence over 3 years in a watershed located in southern Ontario, Canada that is used as a source of drinking water. Methods and Results: Direct DNA extraction from river water followed by quantitative PCR analysis detected thermophilic campylobacters at low concentrations (<130 cells 100 ml^?1) in 57–79% of samples taken from five locations. By comparison, a culture‐based method detected Campylobacter in 0–23% of samples. Water quality parameters such as total Escherichia coli were not highly correlated with Campylobacter levels, although higher pathogen concentrations were observed at colder water temperatures (<10°C). Strains isolated from river water were primarily nalidixic acid‐susceptible Campylobacter lari, and selected isolates were identified as Campylobacter lari ssp. concheus. Campylobacter from wild birds (seagulls, ducks and geese) were detected at a similar rate using PCR (32%) and culture‐based (29%) methods, and although Campylobacter jejuni was isolated most frequently, C. lari ssp. concheus was also detected. Conclusions: Campylobacter were frequently detected at low concentrations in the watershed. Higher prevalence rates using quantitative PCR was likely because of the formation of viable but nonculturable cells and low recovery of the culture method. In addition to animal and human waste, waterfowl can be an important contributor of Campylobacter in the environment. Significance and Impact of the Study: Results of this study show that Campylobacter in surface water can be an important vector for human disease transmission and that method selection is important in determining pathogen occurrence in a water environment.     

Relationships between bacterial genotypes and in vitro virulence properties of Campylobacter jejuni and Campylobacter coli isolated from turkeys

AIMS: Campylobacter isolates from turkeys were genotyped and characterized by their in vitro virulence properties. Relationships between bacterial genotypes and virulence properties were analysed. METHODS AND RESULTS: Isolates were analysed by pulsed-field gel electrophoresis and fla typing. The toxin production was determined on the phenotypic level using a CHO-K1 cell culture model and on the genotypic level using PCR for detection of the cdtA, cdtB and cdtC genes. Although the cdtB gene was detected from 100% of the Campylobacter jejuni and Campylobacter coli isolates we observed three different morphological pictures on the cells. Cytotoxicity was associated with cell distension or cell rounding. All four Camp. coli strains and one Camp. jejuni strain did not produce any cytotoxic changes on the cells. Adhesion, invasion and survival of Campylobacter isolates were determined in a Caco-2 cell culture model. All isolates adhered to and invaded Caco-2 cells, whereas 64.7% of the strains survived for 48 h in the cells. CONCLUSION: Seventeen Campylobacter isolates from turkeys were classified into four groups with regard to their in vitro abilities. Jackknife analysis revealed a strong association between these groups and genotype clusters. SIGNIFICANCE AND IMPACT OF THE STUDY: Typing methods have generally failed to identify strains with specific virulence properties. This study suggests that a relationship between subgroups of Campylobacter with common in vitro virulence characteristics and genotypes exist.     

Evaluation of numerical analysis of PFGE-DNA profiles for differentiating Campylobacter fetus subspecies by comparison with phenotypic, PCR and 16S rDNA sequencing methods

AIMS: To assess the efficacy of numerical analysis of PFGE-DNA profiles for identification and differentiation of Campylobacter fetus subspecies. METHODS AND RESULTS: 31 Camp. fetus strains were examined by phenotypic, PCR- and PFGE-based methods, and the 16S rDNA sequences of 18 strains compared. Numerical analysis of PFGE-DNA profiles divided strains into two clusters at the 86% similarity level. One cluster contained 19 strains clearly identified as Camp. fetus subsp. venerealis. The other cluster comprised 12 strains, of which 10 were unambiguously identified as Camp. fetus subsp. fetus. The remaining two strains were identified as Camp. fetus subsp. venerealis by either phenotypic or PCR methods, but not both. At higher similarity levels, clusters containing isolates from each of two countries were identified, suggesting that certain clones predominate in certain geographical regions. CONCLUSION: Numerical analysis of PFGE-DNA profiles is an effective method for differentiating Camp. fetus subspecies. SIGNIFICANCE AND IMPACT OF THE STUDY: Critical comparison of PFGE, PCR, 16S rDNA sequencing and phenotypic methods for differentiation of Camp. fetus subspecies was attained. Novel phenotypic markers for distinguishing subspecies were identified. Evidence for dominant clones of each subspecies in certain countries was provided.     

The occurrence of Campylobacter subtypes in environmental reservoirs and potential transmission routes

AIM: To identify potential reservoirs and transmission routes of human pathogenic Campylobacter spp. METHODS AND RESULTS: An enrichment PCR method for the detection and identification of Campylobacter jejuni and/or Campylobacter coli in faecal, food and river water samples was applied to 1450 samples of 12 matrix types obtained from a defined geographical area. PCR-positive samples were cultured to yield isolates for typing, and the data for 616 C. jejuni isolates obtained. Serotyping and SmaI macrorestriction profiling using pulsed field gel electrophoresis revealed a high level of diversity within the isolates from each matrix. Campylobacter jejuni and C. coli subtypes indistinguishable from those obtained from human cases were detected in most of the matrices examined. No Campylobacter isolates were isolated from possum faeces. CONCLUSIONS: Ten of the 12 matrices examined may be involved in the transmission of human campylobacteriosis as they contained Campylobacter subtypes also isolated from clinical cases. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate that, for this rural population, a range of potential transmission routes that could lead to campylobacteriosis exist. Their relative importance needs to be assessed from an exposure assessment standpoint.     

Evaluation of the effect of temperature and nutrients on the survival of Campylobacter spp. in water microcosms

Batch microcosms containing various water types (de-ionized and river water with or without sediment), incubated at a range of temperatures (5-37 degrees C), were used to facilitate a comparative evaluation of the significance of such variables and their interactions upon the collective and individual survival of four species of thermophilic Campylobacter. All variables significantly influenced (P < = 0.031) population decay rates. Minimal decay for the group was identified at low temperatures (5 degrees C) in river water, i.e. nutrient-containing microcosms. Collective decay rates within river water microcosms were significantly decreased (P = 0.03) from those observed in de-ionized water, particularly at environmental temperatures (5 and 15 degrees C). However, the increased nutrient levels observed in sediment-containing microcosms did not significantly (P = 0.41) reduce population decay rates. Overall, Camp. jejuni populations demonstrated the most resilience to the environmental stressors evaluated, with the exception of 15 degrees C where Camp. lari was the most persistent. Campylobacter coli and Camp. upsaliensis demonstrated comparable survival characteristics but were less resilient than Camp. jejuni and Camp. lari. These observations identify the suitability of water systems as a reservoir and medium for Campylobacter infection, and potentially identifies Camp. jejuni and Camp. lari as the main protagonists of water-mediated campylobacteriosis.     

A PCR assay for the detection of Campylobacter jejuni and Campylobacter coli in water

A PCR assay has been developed for the detection of Campylobacter jejuni and Camp. coli in water samples. The sample is filtered through a membrane which is subjected to sonication to release the impacted cells. After removal of the filter from the cell suspension and a freeze/thaw cell lysis step, a semi-nested PCR is carried out on the filtrate using the primers CF02, CF03 and CF04 ( Camp. jejuni fla and flaB gene sequences). Incorporation of a sonication stage allows removal of the filter membrane since they have been shown to inhibit the PCR. In experiments with spiked water samples (20 ml) a theoretical sensitivity of 10–20 Campylobacter cells ml^-1 was achieved. Using a sample volume of 100 ml this sensitivity can be increased to approximately 2 Campylobacter cells ml^-1.     

Antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolates from broiler chickens isolated at an Irish poultry processing plant

AIMS: The antibiotic susceptibility of Campylobacter jejuni and Campylobacter coli isolates from broiler chickens were determined in order to evaluate the level of antibiotic resistance of Campylobacter species in the Irish poultry industry. METHODS AND RESULTS: Seventy-eight Camp. jejuni and 22 Camp. coli strains were examined for susceptibility to eight antibiotics using the disc diffusion assay. The highest level of resistance of the Camp. jejuni isolates was recorded to ampicillin (35.9%), followed by 20.5% to tetracycline, 20.5% to naladixic acid, 17.9% to ciprofloxacin, 10.2% to erythromycin, 2.5% to streptomycin and 1.2% to kanamycin. Multidrug resistance to two or more antibiotics was seen for 30.7% of Camp. jejuni strains. Resistance of the Camp. coli isolates was shown to ampicillin (9%) and tetracycline (18.2%). CONCLUSIONS: The majority of Camp. jejuni strains were susceptible to antibiotics commonly used for human therapy. Camp. coli strains showed very low resistance levels and were susceptible to six of the eight antimicrobial agents studied. SIGNIFICANCE AND IMPACT OF THE STUDY: Levels of Camp. jejuni and Camp. coli antimicrobial resistance in Irish poultry production was assessed to determine the current situation in Ireland. The prevalence of antibiotic resistance of Campylobacter strains isolated from broiler chickens was low.     

Coinfection with Campylobacter species: an epidemiological problem?

AIMS: To determine the frequency of coinfection with multiple strains in sporadic cases of human Campylobacter infection. Method and RESULTS: During 1999 10 single colonies of Campylobacter were cultured from each of 53 positive faecal samples. Five isolates were taken from nonselective agar after passive filtration of faecal suspensions and five isolates were taken from selective agar plates. All isolates were sero- and phage typed and their antibiotic resistance determined. Pulsed-field gel electrophoresis and flagellin gene typing were performed on selected isolates. One patient was infected with Camp. coli, the remainder with strains of Camp. jejuni. The majority of patients was infected with a single strain of Campylobacter, but from each of four samples, 7.5%, two strains of Camp. jejuni, confirmed by molecular typing, were identified. CONCLUSION: Coinfection occurs in sporadic cases of campylobacteriosis. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has implications in outbreak investigation when distinct strains have been isolated from epidemiologically related patients and/or the suspected source or vehicle.     

ICC/PCR detection of enteroviruses and hepatitis A virus in environmental samples

This study applied the integrated cell culture/polymerase chain reaction methodology (ICC/PCR) for rapid and specific detection of both cytopathogenic and noncytopathogenic viruses. Results of this study showed that the use of direct RT-PCR or conventional cell culture alone may yield erroneous results with the analysis of environmental samples. The purpose of this study was to compare cultural, molecular, and combined assays for the most effective method of virus detection in variable environmental samples. Using ICC/PCR, stock enterovirus inocula of > or =10 PFU were PCR positive in at least 4/5 replicate flasks after only 5 h of incubation in cell culture, and in all flasks after > or =10 h. An inoculum of one PFU was detected by PCR after 20 h of cell culture incubation while for concentrations of virus below one PFU, 25 h of incubation was sufficient. Similarly, hepatitis A virus (HAV) inocula of 100 MPN/flask, produced indeterminate CPE in cell culture, but were clearly detected by ICC/PCR following 48 h of incubation. Lower levels of HAV, 1 and 10 MPN, were detected by ICC/PCR after 96 to 72 h of incubation, respectively. Cell culture lysates from 11 environmental sample concentrates of sewage, marine water, and surface drinking water sources, were positive for enteroviruses by ICC/PCR compared to 3 positive by direct RT-PCR alone. Results from ICC/PCR eventually agreed with cell culture but required < or =48 h of incubation, compared to as long as 3 weeks for CPE following incubation with BGM and FRhK cells.     

Development of a rapid and sensitive method combining a cellulose ester microfilter and a real-time quantitative PCR assay to detect Campylobacter jejuni and Campylobacter coli in 20 liters of drinking water or low-turbidity waters

Investigations of Campylobacter jejuni and Campylobacter coli in samples of drinking water suspected of being at the origin of an outbreak very often lead to negative results. One of the reasons for this failure is the small volume of water typically used for detecting these pathogens (10 to 1,000 ml). The efficiencies of three microfilters and different elution procedures were determined using real-time quantitative PCR to propose a procedure allowing detection of Campylobacter in 20 liters of drinking water or low-turbidity water samples. The results showed that more than 80% of the bacteria inoculated in 1 liter of drinking water were retained on each microfilter. An elution with a solution containing 3% beef extract, 0.05 M glycine at pH 9, combined with direct extraction of the bacterial genomes retained on the cellulose ester microfilter, allowed recovery of 87.3% (±22% [standard deviation]) of Campylobacter per 1 liter of tap water. Recoveries obtained from 20-liter volumes of tap water spiked with a C. coli strain were 69.5% (±10.3%) and 78.5% (±15.1%) for 91 CFU and 36 CFU, respectively. Finally, tests performed on eight samples of 20 liters of groundwater collected from an alluvial well used for the production of drinking water revealed the presence of C. jejuni and C. coli genomes, whereas no bacteria were detected with the normative culture method in volumes ranging from 10 to 1,000 ml. In the absence of available epidemiological data and information on bacterial viability, these last results indicate only that the water resource is not protected from contamination by Campylobacter.