Identification Of Campylobacter Jejuni Research Articles

Identification of Campylobacter jejuni and Campylobacter coli genes contributing to oxidative stress response using TraDIS analysis

BackgroundCampylobacter jejuni and Campylobacter coli are the major causative agents of bacterial gastroenteritis worldwide and are known obligate microaerophiles. Despite being sensitive to oxygen and its reduction products, both species are readily isolated from animal food products kept under atmospheric conditions where they face high oxygen tension levels.ResultsIn this study, Transposon Directed Insertion-site Sequencing (TraDIS) was used to investigate the ability of one C. jejuni strain and two C. coli strains to overcome oxidative stress, using H2O2 to mimic oxidative stress. Genes were identified that were required for oxidative stress resistance for each individual strain but also allowed a comparison across the three strains. Mutations in the perR and ahpC genes were found to increase Campylobacter tolerance to H2O2. The roles of these proteins in oxidative stress were previously known in C. jejuni, but this data indicates that they most likely play a similar role in C. coli. Mutation of czcD decreased Campylobacter tolerance to H2O2. The role of CzcD, which functions as a zinc exporter, has not previously been linked to oxidative stress. The TraDIS data was confirmed using defined deletions of perR and czcD in C. coli 15-537360.ConclusionsThis is the first study to investigate gene fitness in both C. jejuni and C. coli under oxidative stress conditions and highlights both similar roles for certain genes for both species and highlights other genes that have a role under oxidative stress.

Interpretation for the group standards of the Isolation and Identification of Campylobacter jejuni and Campylobacter coli

Foodborne Campylobacter is recognized as the leading causes of the bacterial diarrheal illness in both developing and developed countries. C. jejuni and C. coli caused 95% of the human campylobacterisosis. Bacteria culture has been recognized as the "Gold standard" for the diagnosis of the Campylobacter infection. The National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention coordinated the experienced researchers from China National Center for Food Safety Risk Assessment and other local Centers for Disease Control and Prevention to write up the standards for entitled Isolation and Identification of Campylobacter jejuni and Campylobacter coli (T/CPMA 006-2019). The standard is drafted with principles of emphasizing the scientific, normative, applicability and feasible nature. This group standard recommended the procedures and steps for the isolation and identification of C. jejuni and C.coli from variant samples. The standard aims to improve the capacity for Campylobacter identification in China.

Validation of the TadpoleTM Campylobacter jejuni Real-Time PCR Identification Kit.

Background: The gene-based real-time PCR method for identification of Campylobacter jejuni is more simple, rapid and accurate than the traditional biochemical method. Objective: A performance validation of the TadpoleTMCampylobacter jejuni Real-Time PCR Identification Kit was performed. Method: The assay uses TaqMan Real-time PCR technology to amplify target genes from isolated colonies. Bacterial deoxyribonucleic acid (DNA) from inclusivity and exclusivity organisms cultured on Columbia Blood Agar, Campy-Cefex agar and modified Charcoal Cefoperazone Deoxycholate was extracted and analyzed on three instruments: Applied Biosystems (ABI) 7500 Fast, ABI StepOne Plus and Bio-Rad CFX96. Results: When 57 distinct strains of C. jejuni were tested for inclusivity, all 57 strains produced positive results on the three instruments. In exclusivity testing, all 35 strains of related organisms, including 7 non-target Campylobacter strains and other common species, produced negative results on the three instruments. The Independent Laboratory validation consisting of an inclusivity and exclusivity evaluation for 10 C. jejuni isolates and 10 nontarget Campylobacter isolates also showed 100% expected results on the three instruments. In addition, in robustness testing, small, deliberate changes to the assay parameters, including cell suspension turbidity, heat lysis time, and DNA template volume in the PCR reaction, did not affect the kit performance. Finally, the combined lot-to-lot and stability study on both the ABI 7500 Fast and the ABI StepOne Plus showed that the 11 C. jejuni strains and 5 nontarget Campylobacter strains can be correctly identified by the three independently manufactured, lots and it supported a shelf life of 9 months when stored at -20°C. Conclusions: The Tadpole method offers a rapid, accurate, and robust alternative for C. jejuni identification. Highlights: Rapid and accurate method to identify C. jejuni, which has a good robustness and high stability. It is flexible and offers the advantages of reduced labor and time saving.

Identification through Culture and Molecular Methods of Campylobacter jejuni, Campylobacter coli and Campylobacter fetus in Surface Waters in Rasht

Backgrounds: As zoonotic infectious agents, Campylobacter spp. are important factors causing gastroenteritis in humans. Surveys show that the three strains; Campylobacter jejuni, Campylobacter coli and Campylobacter fetus play a major role in human infections. Identification of these infectious agents is valuable for sanitary control of disease transmission through water resources.
 Objectives: The aim of this study was identification and molecular diagnosis of Campylobacter jejuni, Campylobacter coli and Campylobacter fetus in surface waters in Rasht.
 Materials and Methods: This cross-sectional study was conducted on 45 samples of surface water in Rasht collected according to water health guidelines. After culture and biochemical tests on collected samples, detection and identification of Campylobacter jejuni, Campylobacter coli and Campylobacter fetus was done using sequence-specific amplification by Multiplex PCR. The results were subjected to statistical analysis using SPSS software.
 Results: Out of 45 samples tested, 6 were positive in culture, four of which were identified as Campylobacter jejuni after biochemical tests. Using Multiplex PCR, 8 samples were positive, from which 3 were Campylobacter jejuni, 1 Campylobacter coli and 4 were positive for both Campylobacter jejuni and Campylobacter coli. All the samples did not yield C. fetus.
 Conclusions: Multiplex PCR is regarded a diagnostic method with higher sensitivity and specificity than compared to methods for Campylobacter. The prevalence of Campylobacter jejuni and Campylobacter coli in surface waters in Rasht is considerable. Therefore, public health measures for the control of these organisms are recommended.

Identification of Campylobacter jejuni and determination of point mutations associated with macrolide resistance using a multiplex TaqMan MGB real-time PCR

Campylobacter jejuni, one of the most important food-borne pathogens, develops resistance to macrolides by acquiring point mutations in the 23S rDNA gene (e.g. A2075G or A2074C) and in ribosomal protein L4 (e.g. G74D or G57D). In this study, a multiplex fluorescence real-time PCR assay, based on TaqMan minor groove binder (MGB) probes, was developed to identify C. jejuni containing mutations associated with macrolide resistance. The VS1-MGB probe was designed based on the VS1 gene and was used to identify C. jejuni. The 23S rDNA-MGB probe was designed to distinguish macrolide resistance mutations in 23S rDNA, whilst 57D-MGB and 74D-MGB were designed to detect resistance mutations in ribosomal protein L4. The specificity and accuracy of the established method were 100% identical to the classic biochemical method, mapA PCR, minimum inhibitory concentration (MIC) determination and DNA sequencing. The linear detection limitation of the method was 0.03ng/reaction genomic DNA and 3CFU/reaction bacterial colonies. In conclusion, this study provides a novel method that can specifically identify C. jejuni and accurately detect the gene mutations associated with macrolide resistance.

Isolation and Identification of Campylobacter jejuni and Campylobacter coli From Various Animal Source Foods by Conventional Methods and PCR

Bu arastirmada Kuzeydogu Anadolu Bolgesinde bulunan farkli market, kasap ve kesimhanelerden alinan tavuk eti, koyun eti (kiyma), sigir eti (kiyma) ve safra kesesi olmak uzere toplam 300 ornek incelendi. Tum ornekler Campylobacter jejuni ve Campylobacter coli yonunden incelendi. Konvansiyonel metodlar ile orneklerin 16’sinda (%5.3) Campylobacter spp. pozitif bulundu. Izolatlar biyokimyasal analizler ve PCR teknigi ile tanimlandi. Izolatlarin 12’sinde (%75) Campylobacter jejuni ve 4’unde (%25) Campylobacter coli identifiye edildi. Sonuc olarak, Campylobacter turlerinin, genellikle insanlara hayvansal gidalarla bulasan akut bakteriyel gastroenteritise sebep olan onemli zoonozlardan oldugu dusunulmektedir.

A Cytolethal Distending Toxin Gene-Based Multiplex PCR Assay for Detection of <i>Campylobacter</i> spp. in Stool Specimens and Comparison with Culture Method

In this study, we evaluated the applicability of cytolethal distending toxin (cdt) gene-based species-specific multiplex PCR for the direct detection and identification of Campylobacter jejuni, C. coli and C. fetus from stool specimens of patients with gastroenteritis in comparison to culture methods. A total of 711 stool specimens were examined for the isolation or detection of campylobacters by using Skirrow's selective agar culture plates, a filtration method and the multiplex PCR assay. Forty-one and 36 C. jejuni strains were isolated by culture and filtration methods, respectively. In addition, 2 and 3 C. coli strains were isolated by Skirrow and the filtration methods, respectively. However, when the multiplex PCR was employed, the cdtB genes of C. jejuni and C. coli were detected in 45 and 4 stool samples, respectively, and 9 C. jejuni PCR-positive samples by multiplex PCR were negative by culture method. Sequence analysis of the PCR products obtained from 8 stool specimens from which campylobacters were not isolated by culture method but the sequences exactly matched with that of the cdtB gene of C. jejuni strain 81-176. None of the remaining stool samples which were culture negative for campylobacters produced any amplicon. Stool samples were defined as Campylobacter-positive if detected by any method. The sensitivity of the multiplex PCR was 83%, which was higher than Skirrow (74%) and filtration method (66%). These data indicate that cdtB gene-based multiplex PCR is a rapid and more sensitive method to identify the most important species of Campylobacter for human diseases. (248).

Isolation and identification of Campylobacter jejuni from poultry carcasses using conventional culture methods and multiplex PCR assay

Campylobacter jejuni is a major cause of food-borne diarrhea in many countries. Poultry and poultry products are known as important sources of human campylobacteriosis. In this study, conventional culture and multiplex PCR methods were compared for the detection of C. jejuni isolated from poultry carcasses. A total of 100 samples, representing 20 broiler flocks, were collected from poultry carcasses after the evisceration stage in the processing line at a commercial broiler slaughtering facility in Mashhad, Iran. In the conventional culture method, samples were processed by enrichment followed by selective plating, and then suspected colonies were isolated on sheep blood agar and tested for morphology, motility, Gram staining, biochemical properties and hippurate hydrolysis activity. For the identification of the Campylobacter genus and its jejuni serovar by molecular methods, a multiplex PCR assay (m-PCR) with two sets of specific primers was used. In the hippurate hydrolysis test of suspected colonies, 76% of the samples were determined as positive, while in the m-PCR assay 28% of cultures harvested were identified as C. jejuni. Two percent of hippurate hydrolyze negative colonies were found positive in the m-PCR test. It appears that the conventional method, based on the hippurate hydrolysis test for detection of C. jejuni, is a less reliable test. The use of the m-PCR method, based on amplification from conserved genes, allows reliable detection and identification of C. jejuni.

Isolation and Identification of Campylobacter jejuni from Diarrhoel Cases of Children in Mosul City

The study include the isolation of Campylobacter jejuni (C.jejuni) from children (aging between after birth to two years) with watery or bloody diarrhea in the period from September 2002 to February 2003. The bacterium was identified depending on succession in growth on selective medium: Preston Campylobacter blood-free medium and microscopical examination which revealed that it is gram negative pleomorphic, curved bacillus, S-shaped and gull-winged. Biochemical tests showed its positive reaction for catalase, oxidase and its ability to hydrolyse hippurate and indoxyl acetate but it was negative for urease and lipase. This bacterium can grow at 42o C while it failed to grow at 25o C and it tolerates 1% glycine while it can not grow in 1.5 % NaCl. Additionally the bacterium was sensetive to Nalidixic acid but resistant to Cephalothin.

Evaluation of a PCR assay for the detection and identification of Campylobacter jejuni and Campylobacter coli in retail poultry products

A PCR-based method was applied to Campylobacter detection in poultry samples at the retail level. In total, 73 retail poultry samples purchased from supermarkets in the Basque Country area in the north of Spain were examined using both culture and molecular (alternative) methods. In our routine method, the worldwide ISO 10272:1995 standard of Preston broth incubated at 42 °C for conventional Campylobacter detection was adopted. The molecular method was comprised of a DNA extraction kit consisting of a single polypropylene spin column and PCR amplification of the Campylobacter 16S rRNA gene. A total of 54 raw samples were positive by either PCR or culture; among these, 50 were found to be positive by conventional plating and 54 by PCR. Concordant results, i.e., positive and negative in both methods, were found in 64 samples (94.1%). All positive samples by culture were also positive by PCR, resulting in 100% of positive concordance. Two samples (2.9%) positive after retesting by PCR were considered to be false-negatives. The detection limit of the PCR method was 5 CFUs that corresponded to 0.2 CFUs per 5 μl in the PCR mixture. The percentages of samples that required enrichment to prove Campylobacter presence were moderate, 18% by culture and 13% by PCR. Total analysis time was reduced to a few hours (within the working day) or 24 h when enrichment was required. Therefore, this PCR method proved to be useful as a routine diagnostic test for Campylobacter detection and confirmation of C. jejuni and C. coli in naturally contaminated poultry samples.

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

To identify potential reservoirs and transmission routes of human pathogenic Campylobacter spp. 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. 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. 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.

Comparison of the BAX® System with a multiplex PCR method for simultaneous detection and identification of Campylobacter jejuni and Campylobacter coli in environmental samples

The Campylobacter detection is performed by conventional culture methods and the identification of Campylobacter jejuni and Campylobacter coli is principally based on the hippurate hydrolysis test. The two major drawbacks of this biochemical test for species identification include the inconsistency of the results and the presence of atypical strains, which can lead to the misidentification of an isolate. As an alternative, multiplex polymerase chain reaction (mPCR) protocols for the simultaneous detection and identification of different Campylobacter species have been developed. This study examined the performances of an experimental BAX® System assay for the C. jejuni and C. coli identification in comparison to a multiplex PCR protocol recently published. The samples tested were represented by 106 environmental swabs collected on Teflon strips and tables, stainless steel saws, hooks and trays, ceramic floors and walls, as well as equipment surfaces, located in a swine ( N=50) and a poultry ( N=56) slaughterhouse. The highest Campylobacter detection rate was obtained after 48 h of enrichment by using both the PCR procedures. After 24 h, the BAX® System provides a more rapid and accurate Campylobacter detection and identification assay than the multiplex PCR. Except for two samples, all the broths where Campylobacter cells were detected after 24 or 48 h of enrichment, with at least one of the PCR protocols, gave Campylobacter colonies using the culture method.

Campylobacter contamination in French chicken production from farm to consumers. Use of a PCR assay for detection and identification of Campylobacter jejuni and Camp. coli

Campylobacter contamination in French chicken production from farm to consumers. Use of a PCR assay for detection and identification of Campylobacter jejuni and Camp. coli

Campylobacter contamination in French chicken production from farm to consumers. Use of a PCR assay for detection and identification of Campylobacter jejuni and Camp. coli.

Campylobacter contamination in French chicken production from the farm to the consumer was determined using a PCR assay for bacteria detection and identification. Samples were bird droppings from poultry houses, neck skins, livers, hearts, gizzards, wings, legs and escalopes from slaughterhouses and gizzards, legs, drumstick, breast and escalopes from a supermarket. Bacterial DNA extraction was performed after an enrichment step in a broth and was followed by PCR. An internal control (IC) was used for both DNA extraction and PCR. Campylobacter were detected in 79.2% of poultry houses. Of the 303 samples, 201 were Campylobacter-positive (i.e. 66.3%) including 43.2% faecal samples, 5.6% slaughterhouse samples and 17.5% supermarket samples. There was no significant difference between the molecular method and the conventional culture technique for Campylobacter detection whatever the samples. The sensitivity was 5 UFC g(-1) of samples and 1.5 x 10(3) UFC ml(-1) of enrichment broth. The use of IC revealed PCR inhibition in 13 samples and problems in the DNA extraction in five samples. Significant Campylobacter contamination affects all stages of French chicken production. The understanding of Campylobacter contamination at different levels of chicken production and the determination of the best place(s) for intervention are important for significantly decreasing Campylobacteriosis. Our technique is rapid and can be used on different chicken samples for Campylobacter detection and identification.

Evaluation of a commercial automated ELISA and PCR-method for rapid detection and identification of Campylobacter jejuni and C. coli in poultry products

Two rapid methods for detection and identification of Campylobacter jejuni andCampylobacter coli in naturally contaminated poultry products were evaluated for their applicability in routine studies. These methods were a commercial automated enzyme-linked immunosorbent assay (ELISA) for detection of thermophilic campylobacters in food, and C. jejuni -specific Polymerase chain reaction (PCR) analysis, which included a sample preparation method, based on Buoyant Density Centrifugation (BDC). Both methods were applied to the samples (97 samples) after a 48h enrichment procedure. The automated ELISA proved to be an easily repeatable and reliable method for detection of thermophilic campylobacters in food. The BDC-PCR method, which detected C. jejuni directly from the enrichment broth, was also reliable but not as simple as the ELISA. The analysis time for the ELISA-based method, starting from enrichment, took a minimum 2·5 working days, while the BDC-PCR method required 3 working days. Our study with a limited number of samples suggest that both detection methods are useful for monitoring C. jejuni on chicken meat.

Serotyping and Identification of Campylobacter jejuni and Campylobacter coli Strains of Human and Animal Origin Using the PCR Method

Steinhauserova I., K. Fojtikova: Serotyping and Identification of Campylobacter jejuni and Campylobacter coli Strains of Human and Animal Origin Using the PCR Method. Acta Vet. Brno 1999, 68: 149–154. A total number of 178 strains of Campylobacter spp. from human patients suffering from diarrhea and from the intestinal content of slaughtered pigs and poultry was isolated during years 1996 to 1997. Campylobacter strains were isolated and identified by standard tests and the PCR method using fla A and fla B, as well. Isolates originating from human patients were identified as Campylobacter jejuni (98% = 108 strains) and C. coli (2% = 2 strains). Campylobacter spp. (20) strains obtained from slaughtered pigs were identified using standard tests in 45% (9 strains) and 40% (8 strains) as C. coli and C. jejuni, respectively. Strains of Campylobacter spp. (48) isolated from slaughtered poultry were identified as C. jejuni (89% = 42 strains). Standard tests failed to identify 9 strains; 6 strains were identified as Campylobacter jejuni and C. coli using the PCR method. Serotyping using 34 antisera of the Penner’s serotyping scheme was performed in 130 strains of Campylobacter jejuni isolated from poultry and human patients. This method was suitable for identification of almost 80% of C. jejuni strains. We found 10 different serotypes of human C. jejuni strains. There were serotypes (HS) 4, 1 and 9 (32%, 23% and 15%, respectively) predominating in the human population; they were followed by serotypes (HS) 10, 2 and 23 (8%, 5% and 3%, respectively). Animal strains included 7 (HS) serotypes. Like in the human strains, the serotype 4, found in 37% of examined isolates, was predominating. Serotypes 23 and 1 (17% and 15%, respectively) were the next most frequent ones. Comparing the obtained serotypes of human and animal strains we see that there are only 4 identical ones (i.e., 4, 1, 10, 23), which are, however, most frequently occurring in both groups of strains. The PCR methods and serotyping may facilitate and make more accurate the results of standard cultivation and in epidemiologically serious cases help in explaining the route of transmission. Campylobacter jejuni/coli, PCR, HS antigen, food-borne diseases

Identification of Campylobacter jejuni on the basis of a species-specific gene that encodes a membrane protein.

To facilitate discrimination between the closely related enteropathogens Campylobacter jejuni and C. coli, unique differences in antigenic surface structure were examined. A genomic library of C. jejuni 81116 was constructed in plasmid pBluescriptIISK- and expressed in Escherichia coli K-12. Rabbit hyperimmune serum raised against C. jejuni ATCC 29428 recognized a clone expressing a C. jejuni 24-kDa membrane-associated protein. Antiserum raised against sonicated recombinant E. coli expressing the 24-kDa protein reacted with C. jejuni, whereas C. coli did not react specifically. Determination of the nucleotide sequence of the DNA insert of this recombinant plasmid revealed an open reading frame encoding 214 amino acids; the gene was designated mapA; and its gene product was designated MAPA. The 18 N-terminal amino acid residues constitute a signal sequence characteristic of prokaryotic membrane lipoproteins. In a dot blot hybridization assay with a mapA probe, 120 clinical isolates of C. jejuni were unequivocally discriminated from 126 other campylobacters, including 34 C. coli isolates. A PCR test based on the mapA sequence was developed for identification of C. jejuni. A PCR product was obtained with all of the clinical isolates of C. jejuni tested from human, dog, cat, bovine calf, and chicken sources. Recombinant MAPA with an added C-terminal six-histidine tail was affinity purified and used to immunize rabbits. The rabbit anti-MAPA serum specifically recognized the protein in whole cells of C. jejuni on Western blots (immunoblots). The MAPA protein was present in all of the C. jejuni strains tested and was absent in C. coli and related campylobacters.

Identification of Campylobacter jejuni and C. coli using the rpoB gene and a cryptic DNA fragment from C. jejuni

Campylobacter jejuni (Cj) and C. coli (Cc) clinical isolates, obtained from three different sources, were characterized using two Cj DNA probes, CJ01 and CJ02. These probes were selected at random by virtue of their stability in Escherichia coli (Ec). CJ01 hybridized specifically with DNA from Cj reference strains, but not with DNA from Cc, C. lari (Cl) nor C. fetus (Cf) reference strains. Using clinical isolates characterized by genome-genome hybridization and biotype, CJ01 hybridized with DNA derived from all Cj strains. However, DNA from four out of ten Cc strains, from three different sources, also hybridized with CJ01, suggestive of this region being heterogeneous between clinical isolates of both species. The nucleotide sequence analysis of CJ01 reveals two incomplete open reading frames (ORFs) that did not show significant homology with any other known sequences. CJ02 hybridized specifically with DNA from Cj and Cc reference strains, but not with DNA from Cl and Cf reference strains. The specificity and sensitivity were maintained upon hybridization with DNA from 31 clinical isolates. CJ02 has an uninterrupted ORF whose deduced amino-acid sequence showed extensive homology with the central region of the Ec and Salmonella typhimurium (St) RNA polymerase β subunits (52 and 66% similarity, respectively). The most conserved segments correspond to putative functional domains.

Identification of Campylobacter jejuni and Campylobacter coli antigens with mucosal and systemic antibodies

The development of a rapid and specific diagnostic assay for Campylobacter infections is important in determining the etiology of acute diarrhea in humans. Studies have shown that sonicated whole bacteria or partially purified antigens cross-reacted with antibodies against other closely related bacteria. To solve the problems of specificity, we identified specific antigens of Campylobacter jejuni and Campylobacter coli for use in diagnostic assays. We investigated the responses of serum, urine, and intestinal lavage antibodies in infected (fed live bacteria) and parenterally immunized (intraperitoneal injection of sonicated whole bacteria with adjuvant) mice directed against C. jejuni or C. coli by Western blot (immunoblot) analysis. Antibody responses were examined weekly for up to 28 days. Fewer antigens were detected by urinary and intestinal lavage fluid immunoglobulin A (IgA) than serum IgG and IgM for both parenterally immunized and infected mice. Serum from parenterally immunized mice detected more antigens than that from infected mice. Two high-molecular-weight antigens (62,000 and 43,000) were predominantly detected by serum, urine, and intestinal lavage fluids of both parenterally immunized and infected mice. Serum antibodies from 28-day parenterally immunized mice detected one antigen specific to C. coli with a molecular weight of 38,000 and one antigen specific to C. jejuni with a molecular weight of 27,000. An immunodominant protein with a molecular weight of 31,000 common to both C. jejuni and C. coli was also recognized by serum antibodies from parenterally immunized mice.

Identification of Campylobacter jejuni and C. coli by gel electrophoresis of the outer membrane proteins.

Analysis of the electrophoretic profiles of the outer membrane proteins could be used to differentiate Campylobacter jejuni (16 strains) from Campylobacter coli (10 strains). This observation was confirmed by the study of DNA homology obtained by a quantitative filter hybridization method. The hippurate hydrolysis test gave a poor correlation with the results of differentiation obtained by DNA homology studies and outer membrane protein profile.