An outbreak of Campylobacter jejuni infections associated with food handler contamination: the use of pulsed-field gel electrophoresis

In 1998, an outbreak of Campylobacter jejuni infections occurred in Kansas among persons attending a school luncheon; community cases were also reported. In a cohort study of luncheon attendees, 27 (17%) of 161 persons reported illness. Consuming gravy (relative risk [RR], 4.2; 95% confidence interval [CI], 1.5-11.7) or pineapple (RR, 2.4; 95% CI, 1.0-5.7) was associated with illness. Both foods were prepared in a kitchen that served 6 other schools where no illness was reported. A cafeteria worker at the luncheon had a diarrheal illness and was the likely source of the outbreak. The pulsed-field gel electrophoresis (PFGE) patterns of the isolates from the food handler and those of 8 lunch attendees were indistinguishable. Isolates from 4 community patients differed. This was the first use of PFGE in a Campylobacter outbreak in the United States; its use was critical in determining that community cases were not linked.

Detection and initial characterization of novel capsular polysaccharide among diverse Campylobacter jejuni strains using alcian blue dye

We have recently demonstrated that most strains of Campylobacter jejuni produce capsular polysaccharide (CPS), which can be detected by immunoblotting with homologous Penner antisera on polyvinylidene difluoride membranes (A. V. Karlyshev, D. Linton, N. A. Gregson, A. J. Lastovica, and B. W. Wren, Mol. Microbiol. 35:529-541, 2000). In this report, we describe a universal and rapid staining procedure using Alcian blue for C. jejuni CPS, which does not rely on the availability of antisera and identifies CPS in untypeable strains. Furthermore, Alcian blue staining identified CPS in its lipid-free form directly on Tricine gels, and we demonstrate that CPS is thermostable and is accumulated in the culture supernatant in a lipid-free form. The identification of a newly described CPS and its lipid-free form in C. jejuni should prove invaluable in studying the pathogenesis and epidemiology of this important pathogen.

Prevalence of Salmonella, Campylobacter and VTEC on pig farms

Four different pig farms were sampled for the prevalence of Salmonella, Campylobacter and verotoxigenic E. coli (VTEC). Pigs of different age groups and pigs of the same age were tested by taking rectal swabs. The farm environment was tested by examining overshoes, and the feed and drinking water in the pens. From a total of 215 rectal samples of individual pigs, 15 rectal samples taken from animals at the same farm were positive for Salmonella. The Salmonella status of the pigs at this farm differed from one age group to another. S. Typhimurium was isolated from all the positive rectal samples and S. Typhimurium and S. Schwarzengrund were isolated from the environment. On two other farms Salmonella was only present in the environment with S. London and S. Typhimurium as serotypes. The presence of Campylobacter was tested in 150 rectal swabs, 51 of these, spread over the four farms, turned out to be positive. At all four pig farms Campylobacter was isolated from the environment as well. All the strains were identified as Campylobacter coli by a species-specific PCR. To determine if pigs are a reservoir of VTEC a total of 289 samples were screened for the presence of VTEC and 54 strains were isolated that each carried one virulence gene. Thirty-one strains carried the vt2e variant of the vt2 gene wich causes the endema disease in young pigs, four strains harboured the hlyA gene and 19 the eaeA gene.

Multilocus sequence typing system for Campylobacter jejuni

The gram-negative bacterium Campylobacter jejuni has extensive reservoirs in livestock and the environment and is a frequent cause of gastroenteritis in humans. To date, the lack of (i) methods suitable for population genetic analysis and (ii) a universally accepted nomenclature has hindered studies of the epidemiology and population biology of this organism. Here, a multilocus sequence typing (MLST) system for this organism is described, which exploits the genetic variation present in seven housekeeping loci to determine the genetic relationships among isolates. The MLST system was established using 194 C. jejuni isolates of diverse origins, from humans, animals, and the environment. The allelic profiles, or sequence types (STs), of these isolates were deposited on the Internet (http://mlst.zoo.ox.ac.uk), forming a virtual isolate collection which could be continually expanded. These data indicated that C. jejuni is genetically diverse, with a weakly clonal population structure, and that intra- and interspecies horizontal genetic exchange was common. Of the 155 STs observed, 51 (26% of the isolate collection) were unique, with the remainder of the collection being categorized into 11 lineages or clonal complexes of related STs with between 2 and 56 members. In some cases membership in a given lineage or ST correlated with the possession of a particular Penner HS serotype. Application of this approach to further isolate collections will enable an integrated global picture of C. jejuni epidemiology to be established and will permit more detailed studies of the population genetics of this organism.

Acute ophthalmoparesis (without ataxia) associated with anti-GQ1b IgG antibody: clinical features

OBJECTIVE

To examine the clinical features of acute ophthalmoparesis (AO) (without ataxia) associated with anti-GQ1b immunoglobulin G (IgG) antibody.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Twenty-one subjects with AO (without ataxia) who had anti-GQ1b IgG.

METHODS

Clinical features of 21 subjects with AO were analyzed.

RESULTS

Seventeen had symptoms of antecedent infection. Gaze limitation was bilateral in 16 subjects and unilateral in five, indicative that laterality does not always negate AO. Nine subjects showed abducens paresis, and two limitation of abduction and adduction. Eight, who initially had bilateral abducens palsy, subsequently had impairment of adduction and vertical movement. These showed that bilateral abducens palsy followed by oculomotor nerve involvement is characteristic of AO. Muscle stretch reflexes were normal in nine subjects, hypoactive in eight, absent in three, and brisk in one. Distal paresthesias were present in seven subjects. Acellular cerebrospinal fluid (CSF) associated with raised protein concentration was detected in three.

CONCLUSIONS

Antecedent infectious symptoms, characteristic limitation of ocular movement, areflexia, distal paresthesias, and CSF albuminocytologic dissociation are useful markers for diagnosing AO as well as anti-GQ1b IgG. AO can be considered a mild form of Miller Fisher syndrome or a regional variant of Guillain-Barré syndrome.

Detection of thermophilic Campylobacter from sparrows by multiplex PCR: the role of sparrows as a source of contamination of broilers with Campylobacter

The best combination of primers and the annealing temperature of multiplex PCR for Campylobacter jejuni, Campylobacter coli, and Campylobacter lari were examined. The multiplex PCR was able to detect type strains of the three species. All results of identification of wild strains (30 strains of C. jejuni, 20 strains of C. coli, and 4 strains of C. lari) by the multiplex PCR coincided with those of the conventional biochemical identification tests, suggesting that the multiplex PCR can simultaneously differentiate C. jejuni, C. coli, and C. lari from wild strains of campylobacters easily and rapidly. Campylobacters were detected from sparrow feces by the multiplex PCR and antimicrobial sensitivities of the strains were determined to discuss the role of sparrows in contamination of broilers with C. jejuni. Three out of 13 strains of C. jejuni isolated from sparrow feces showed quinolone resistance. From the frequent use of quinolones for treatment of industrial animals like chickens, pigs, and cows, the three strains of quinolone-resistant C. jejuni in sparrows must have been originated from those industrial animals. Sparrows that have quinolone-resistant C. jejuni were considered to have contacted with industrial animals or thier feed. It may be presumed, on the contrary, that C. jejuni in sparrows could be a potential source of contamination of broilers.

Identification of taxonomic and epidemiological relationships among Campylobacter species by numerical analysis of AFLP profiles

Amplified fragment length polymorphism (AFLP)-based profiling was performed on 138 strains representing all named Campylobacter species and subspecies. Profiles of 15/16 species comprised 6 to greater than 100 fragments and were subjected to numerical analysis. The mean similarity of 48 duplicate, outbreak and/or 'identical' strain profiles exceeded 94%. Species were clearly distinguished at the 17.90% similarity (S-) level in the dendrogram. Subspecies of Campylobacter jejuni and Campylobacter hyointestinalis, and biovars of Campylobacter lari and Campylobacter sputorum were distinguished at higher S-levels. All outbreak or 'genetically identical' strains of C. jejuni subsp. jejuni, Campylobacter coli, C. hyointestinalis and C. sputorum clustered at S-levels >92% and were distinguished from unrelated strains. Numerical analysis of AFLP profiles is useful for concurrent identification of taxonomic and epidemiological relationships among most Campylobacter species.

Campylobacter contamination of raw meat and poultry at retail sale: identification of multiple types and comparison with isolates from human infection

Campylobacter species are the major cause of acute bacterial enteritis reported in the United Kingdom, nonetheless many aspects of campylobacteriosis epidemiology remain poorly understood. The aim of this study was to determine the prevalence of Campylobacter jejuni and Campylobacter coli in fresh bovine, ovine, and porcine liver and chicken portions from retail outlets and compare strain subtype distributions with those associated with cases of human campylobacteriosis occurring within the same period and study area. Meat samples were examined by both enrichment culture and direct plating, and Campylobacter isolates were subjected to the same test procedures (identification, serotyping, phagetyping, resistotyping) applied to the clinical strains. Campylobacter species were isolated from 73.2% of 489 samples examined. Chicken exhibited the highest contamination rate (83.3%), followed by lamb (72.9%), pig (71.7%), and ox (54.2%) liver. C. jejuni predominated in chicken (77.3%), lamb (75.0%), and ox (49.0%) liver, and C. coli predominated in pigs' liver (42.4%). Campylobacter fetus was identified in 12.5% of ox liver samples and also in pig and lamb. Of the human isolates, 89.3% were C. jejuni and 10.7% C. coli. The greatest variation in C. jeuni subtypes was observed among the chicken isolates (57 sero/phage-types), followed by human (48 types) and lamb (30 types). A significant proportion of the chicken and lamb isolates shared identical subtypes with the human strains, indicative of their role as potential sources of infection. Almost 30% of samples yielded multiple strains of Campylobacter, a finding that reinforces the epidemiological importance of selecting and testing more than one presumptive isolate per sample.

Family clusters of campylobacter infection

Possible family clusters of campylobacter infection among isolates referred to a single, large public health laboratory were reviewed to determine the proportion of clusters associated with more than one strain of campylobacter. A total of 23 clusters, each made up of members of a single household infected within two months of each other, were identified between September 1996 and January 1999. These accounted for about 5% of all campylobacter infections confirmed during the study period. Thirteen of these families were infected with single strains of C. jejuni and one with C. coli. In ten families specimens were taken over intervals ranging from six to 56 days. In eight clusters more than one strain of C. jejuni was identified and in one family two patients were infected with C. jejuni and one with C. lari. These findings are consistent with the observation that potential sources of campylobacter infection may be contaminated with more than one strain.

Antimicrobial resistance profiling and DNA Amplification Fingerprinting (DAF) of thermophilic Campylobacter spp. in human, poultry and porcine samples from the Cork region of Ireland

Antimicrobial resistance (R) typing and DNA Amplification Fingerprinting (DAF) of a random collection of 84 Irish thermophilic Campylobacter isolates is described. The collection included human, veterinary (porcine) and poultry isolates cultured between 1996 and 1998 in the Cork region of Ireland. Biochemical and molecular methods were used to identify Campylobacter jejuni and Camp. coli. Many of these isolates were simultaneously resistant to several common antimicrobial agents. In particular, resistance to ampicillin, spectinomycin, sulphafurazole and tetracycline was common. A total of 74 DAF profiles was identified among the study collection, showing a high degree of diversity. Dendrogram analysis of the DNA patterns identified three main clusters at the 50% similarity level, which included two clusters of Camp. coli and a third containing a mixture of Camp. jejuni and Camp. coli.

Identification of ciprofloxacin-resistant Campylobacter jejuni by use of a fluorogenic PCR assay

Fluoroquinolones are one class of antimicrobial agents commonly used to treat severe Campylobacter jejuni infection. C. jejuni strains resistant to high levels of the fluoroquinolone ciprofloxacin (MIC >/=16 microg/ml) have been predominantly characterized with a C-->T transition in codon 86 of gyrA. The gyrA gene encodes one subunit of DNA gyrase, which is a primary target for fluoroquinolone antibiotics. This study establishes a rapid PCR-based TaqMan method for identifying ciprofloxacin-resistant C. jejuni strains that carry the C-->T transition in codon 86 of gyrA. The assay uses real-time detection, eliminating the need for gel electrophoresis. Optimization of the assay parameters using purified Campylobacter DNA resulted in the ability to detect femtogram levels of DNA. The method should be useful for monitoring the development of ciprofloxacin resistance in C. jejuni. Compiled nucleotide sequence data on the quinolone resistance-determining region of gyrA in Campylobacter indicate that sequence comparison of this region is a useful method for tentative identification of Campylobacter isolates at the species level.

Campylobacter jejuni infection and Guillain-Barré syndrome: a case-control study. Emilia-Romagna Study Group on Clinical and Epidemiological problems in neurology

We performed a case-control study to investigate the association between Campylobacter jejuni (CJ) infection and Guillain-Barr| syndrome (GBS) or Miller-Fisher syndrome. We compared 60 cases with 109 hospital controls matched for age, gender, hospital and geographical location. To diagnose the CJ infection, we considered the association between serologic positivity for CJ and a previous diarrheal illness within 3 months of inclusion in the study. Fifteen percent of cases versus 5% of hospital controls had CJ infection (p < 0.003, OR = 3.96, 95% CI: 1.0817.85). However, CJ infection was related to GBS only if it occurred during the previous month (p< 0.001, OR = 7.29, 95% CI: 1.4371.28). No statistical differences were found between the cases who were positive for CJ infection and those who were negative for CJ infection when studied by stepwise multivariate logistic regression for age, gender, clinical and electrophysiological features and outcome. Recent CJ infection may be a risk factor for GBS.

Evaluation of phenotypic and genotypic methods for subtyping Campylobacter jejuni isolates from humans, poultry, and cattle

Six methods for subtyping of Campylobacter jejuni were compared and evaluated with a collection of 90 isolates from poultry, cattle, and sporadic human clinical cases as well as from a waterborne outbreak. The applied methods were Penner heat-stable serotyping; automated ribotyping (RiboPrinting); random amplified polymorphic DNA typing (RAPD); pulsed-field gel electrophoresis (PFGE); restriction fragment length polymorphisms of the flagellin gene, flaA (fla-RFLP); and denaturing gradient gel electrophoresis of flaA (fla-DGGE). The methods were evaluated and compared on the basis of their abilities to identify isolates from one outbreak and discriminate between unrelated isolates and the agreement between methods in identifying clonal lines. All methods identified the outbreak strain. For a collection of 80 supposedly unrelated isolates, RAPD and PFGE were the most discriminatory methods, followed by fla-RFLP and RiboPrinting. fla-DGGE and serotyping were the least discriminative. All isolates included in this study were found to be typeable by each of the methods. Thirteen groups of potentially related isolates could be identified using a criterion that at least four of the methods agreed on clustering of isolates. None of the subtypes could be related to only one source; rather, these groups represented isolates from different sources. Furthermore, in two cases isolates from cattle and human patients were found to be identical according to all six methods.

Sequence polymorphism, predicted secondary structures, and surface-exposed conformational epitopes of Campylobacter major outer membrane protein

The major outer membrane protein (MOMP), a putative porin and a multifunction surface protein of Campylobacter jejuni, may play an important role in the adaptation of the organism to various host environments. To begin to dissect the biological functions and antigenic features of this protein, the gene (designated cmp) encoding MOMP was identified and characterized from 22 strains of C. jejuni and one strain of C. coli. It was shown that the single-copy cmp locus encoded a protein with characteristics of bacterial outer membrane proteins. Prediction from deduced amino acid sequences suggested that each MOMP subunit consisted of 18 beta-strands connected by short periplasmic turns and long irregular external loops. Alignment of the amino acid sequences of MOMP from different strains indicated that there were seven localized variable regions dispersed among highly conserved sequences. The variable regions were located in the putative external loop structures, while the predicted beta-strands were formed by conserved sequences. The sequence homology of cmp appeared to reflect the phylogenetic proximity of C. jejuni strains, since strains with identical cmp sequences had indistinguishable or closely related macrorestriction fragment patterns. Using recombinant MOMP and antibodies recognizing linear or conformational epitopes of the protein, it was demonstrated that the surface-exposed epitopes of MOMP were predominantly conformational in nature. These findings are instrumental in the design of MOMP-based diagnostic tools and vaccines.

Milkborne campylobacter infection in Hungary

In April 1998, an annual 2-day animal farm sale was held in Hódmezóvásárhely, where 500 to 600 visitors consumed unpasteurized milk. The first signs of disease began 2 days after the end of the sale. Fifty-two people from a wide age range fell ill, primarily with inflammatory enteritis. These cases included 34 with Campylobacter positivity: 30 with Campylobacter jejuni and 4 with Campylobacter coli. Environmental samples (raw milk, udder swabs, and rectal swabs from 12 cows in the suspected herd) were tested 2 weeks after the first signs of the disease, and two rectal swabs were found to be positive for C. jejuni. Initially, the epidemic seemed to be sporadic and, accordingly, only 26 human and 2 animal Campylobacter isolates were reserved for randomly amplified polymorphic DNA analysis. This comparative analysis verified that fecally contaminated milk was the source of the outbreak. The DNA-banding patterns of 20 C. jejuni isolates (19 human and 1 animal) were identical. The antibiotic susceptibilities of the Campylobacter isolates were determined, and only six C. jejuni (human) isolates, one C. coli (human) isolate, and one C. jejuni (animal) isolate were resistant to tetracycline, both by disk diffusion and by E test (antimicrobial gradient strip for the quantitative determination of susceptibility or resistance of microorganisms). No plasmid was detected in these tetracycline-resistant isolates. The endotoxin production of Campylobacter isolates was examined via the cytopathogenic effect on the Vero cell line. This effect exhibited various degrees of positivity in 19 cases. Only two human C. jejuni isolates displayed + + + + positivity. Both isolates were from patients who had required antibiotic therapy and hospital care.

Diminution of Campylobacter colonization in neonatal pigs reared off-sow

Pigs may be a natural reservoir of Campylobacter and can be colonized as early as 24 h after birth. The purpose of the present study was to evaluate what effect early removal of piglets from Campylobacter-positive sows has on Campylobacter prevalence in neonates. In two trials, piglets were removed from sows within 24 h of birth and were reared in nurseries isolated from sows for 21 days. From the neonates rectal swabs were cultured for Campylobacter, and Campylobacter status of the isolated piglets was compared to that of littermates reared on sows. The nurseries consisted of wire-floored farrowing crates that were equipped with heaters and self-feeders. In trial I, the Campylobacter prevalence in nursery-reared piglets was 13 of 14 on day 2 and 0 of 14 on day 20. Campylobacter prevalence in the sow-reared piglets was 8 of 9 from days 2 to 20. In trial II, 12 of 29 on day 2, and 5 of 26 on day 20, of the nursery-reared piglets were culture positive for Campylobacter. For the sow-reared piglets, Campylobacter prevalence was 7 of 15 on day 1 and 15 of 15 (100%) on day 20. These data suggest that successful permanent colonization of the gut by Campylobacter is probably related to constant exposure of piglets to Campylobacter-positive feces. Campylobacter prevalence may be diminished in neonates that are reared off-sow in isolated nurseries.

Characterization of gyrA mutations associated with fluoroquinolone resistance in Campylobacter coli by DNA sequence analysis and MAMA PCR

Increasing numbers of fluoroquinolone-resistant Campylobacter coli isolates received at the Minnesota State Public Health Laboratory and at the Centers for Disease Control and Prevention have been a cause for concern. The gyrA quinolone resistance-determining regions of several fluoroquinolone-resistant isolates were sequenced to examine the mechanism of resistance. Ciprofloxacin-resistant C. coli isolates examined by DNA sequencing had a Thr-86 to Ile (ACT-->ATT) gyrA mutation, leading to resistance to fluoroquinolone antibiotics. A mismatch amplification mutation assay polymerase chain reaction protocol was developed to detect this gyrA mutation.

Comparative fingerprinting analysis of Campylobacter jejuni subsp. jejuni strains by amplified-fragment length polymorphism genotyping

Amplified-fragment length polymorphism (AFLP) analysis with the endonucleases BglII and MfeI was used to genotype 91 Campylobacter jejuni subsp. jejuni strains from outbreaks and sporadic cases. AFLP-generated fragments were labeled with fluorescent dye and separated by capillary electrophoresis. The software packages GeneScan and GelCompar II were used to calculate AFLP pattern similarities and to investigate phylogenetic relationships among the genotyped strains. The AFLP method was compared with two additional DNA-based typing methods, pulsed-field gel electrophoresis (PFGE) using SmaI and restriction fragment length polymorphism analysis on PCR products (PCR-RFLP) of the flaA and flaB genes. We found that AFLP analysis of C. jejuni strains is a rapid method that offers better discriminatory power than do both PFGE and PCR-RFLP. AFLP and, to a lesser extent, PCR-RFLP could differentiate strains within the same PFGE profiles, which also makes PCR-RFLP an alternative to PFGE. We were able to clearly distinguish 9 of 10 recognized outbreaks by AFLP and to identify similarities among outbreak and sporadic strains. Therefore, AFLP is suitable for epidemiological surveillance of C. jejuni and will be an excellent tool for source identification in outbreak situations.

The incidence and PCR detection of Campylobacter upsaliensis in dogs and cats

A study was made of the incidence of Campylobacter upsaliensis among dogs and cats suffering from acute or chronic diarrhoea; 225 dogs and cats were examined and 51 strains were identified, 16 (7%) of which were Camp. upsaliensis. When rectal swabs were taken from a control group of 126 dogs and cats without clinical symptoms, 19 Campylobacter spp. and four Camp. upsaliensis were identified. All the Camp. upsaliensis strains were isolated in dogs. The Campylobacter strains were identified on the basis of their biochemical characteristics and by PCR (polymerase chain reaction).

Application of the 5'-nuclease PCR assay in evaluation and development of methods for quantitative detection of Campylobacter jejuni

Campylobacter jejuni is recognized as a leading human food-borne pathogen. Traditional diagnostic testing for C. jejuni is not reliable due to special growth requirements and the possibility that this bacterium can enter a viable but nonculturable state. Nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. In this article, we present a 5'-nuclease PCR assay for quantitative detection of C. jejuni and describe its evaluation. A probe including positions 381121 to 381206 of the published C. jejuni strain NCTC 11168 genome sequence was identified. When this probe was applied, the assay was positive for all of the isolates of C. jejuni tested (32 isolates, including the type strain) and negative for all other Campylobacter spp. (11 species tested) and several other bacteria (41 species tested). The total assay could be completed in 3 h with a detection limit of approximately 1 CFU. Quantification was linear over at least 6 log units. Quantitative detection methods are important for both research purposes and further development of C. jejuni detection methods. In this study, we used the assay to investigate to what extent the PCR signals generated by heat-killed bacteria interfere with the detection of viable C. jejuni after exposure at elevated temperatures for up to 5 days. An approach to the reduction of the PCR signal generated by dead bacteria was also investigated by employing externally added DNases to selectively inactivate free DNA and exposed DNA in heat-killed bacteria. The results indicated relatively good discrimination between exposed DNA from dead C. jejuni and protected DNA in living bacteria.

Quantitative immunocapture PCR assay for detection of Campylobacter jejuni in foods

The rapid detection of food-borne bacterial pathogens as part of a quality control program is necessary for the maintenance of a safe food supply. In this report, we present our findings for an immunocapture PCR method for the detection of Campylobacter jejuni in foods. The method permits direct detection of the pathogen without an enrichment step and can be performed in approximately 8 h. Assay results are quantitative, and one cell in a milliliter sample can be detected. Application of the method to spiked milk samples and chicken skin washes did not affect the sensitivity of the assay.

Amplified fragment length polymorphism analysis of Campylobacter jejuni strains isolated from chickens and from patients with gastroenteritis or Guillain-Barré or Miller Fisher syndrome

The high-resolution genotyping method of amplified fragment length polymorphism (AFLP) analysis was used to study the genetic relationships between Campylobacter jejuni strains infecting chickens (n = 54) and those causing gastroenteritis in humans (n = 53). In addition, C. jejuni strains associated with the development of Guillain-Barré syndrome (GBS) (n = 14) and Miller Fisher syndrome (MFS) (n = 4), two related acute paralytic syndromes in human, were included. Strains were isolated between 1989 and 1998 in The Netherlands. The AFLP banding patterns were analyzed with correlation-based and band-based similarity coefficients and UPGMA (unweighted pair group method using average linkages) cluster analysis. All C. jejuni strains showed highly heterogeneous fingerprints, and no fingerprints exclusive for chicken strains or for human strains were obtained. All strains were separated in two distinct genetic groups. In group A the percentage of human strains was significantly higher and may be an indication that genotypes of this group are more frequently associated with human diseases. We conclude that C. jejuni from chickens cannot be distinguished from human strains and that GBS or MFS related strains do not belong to a distinct genetic group.

Deoxyribonucleic acid restriction digest patterns in Campylobacter species: a comparison with Penner serotype

Diversity, based on restriction fragment length polymorphism (RFLP) analysis, was studied in 48 strains of Campylobacter, comprising 27 chicken and 21 human strains of C. jejuni and C. coli, using genomic Southern hybridisation. Restriction digests of chromosomal DNA were prepared by treating with HaeIII and probed using a C. jejuni DNA probe. Nineteen distinct hybridisation patterns were identified, and differences in hybridisation pattern between members of the two species, and in individual strains of the same species, were seen. The method described proved more discriminatory than the Penner serotype, as strains from the same serotype were distinguished. The relative simplicity of the patterns obtained, together with the apparent diversity identified among individual strains and species, suggests that DNA fingerprinting using the C. jejuni DNA probe could be a useful identification method in epidemiological studies of Campylobacter infection in Nigeria.