Detection of Campylobacter antibodies in sheep sera by a Dot-ELISA using acid extracts from c. fetus ssp. fetus and c. jejuni strains and comparison with a complement fixation test

In this study, a dot-enzyme-linked immunosorbent assay (Dot-ELISA) was evaluated in comparison with a complement fixation test (CFT) for the detection of Campylobacter antibodies in sheep sera. Acid glycine extracts (AGE) of both Campylobacter fetus ssp. fetus and Campylobacter jejuni strains that had been isolated from the gall-bladder of slaughtered sheep was used as antigen in both tests. A total of 153 sheep sera from aborted (74) and slaughtered (79) sheep were examined by both Dot-ELISA and CFT. Twenty-two sera showed anti-complementary activity were not suitable for CFT. Of the 22 sera showing anti-complementary activity, two sera were found to be positive in Dot-ELISA. Eighty-eight (67.2%) of the remaining 131 sera were negative by both Dot-ELISA and CFT using AGE of both Campylobacter strains whereas 43 sera (32.8%) gave different reaction patterns in Dot-ELISA and CFT with the extracts of both Campylobacter strains. Twelve sera were positive by both tests using AGE of C. fetus ssp. fetus but CFT failed to detect antibodies in nine of these sera when AGE of C. jejuni was used. Twelve sera were positive by both tests only when AGE of C. fetus ssp. fetus was used. Eleven sera were positive only by CFT. Seven of these reacted only with the AGE of C. fetus ssp. fetus and four sera were positive by using AGE of both Campylobacter strains. The remaining eight sera were found to be positive only by dot-immunobinding assay either with the AGE of both Campylobacter strains or with the AGE of one of the Campylobacter strains. It is concluded that Dot-ELISA using AGE from C. fetus ssp. fetus could be employed for the detection of Campylobacter antibodies in sheep sera and the additional use of AGE from C. jejuni as antigen appeared not to be profitable for this purpose.

Effect of drinking water chlorination on Campylobacter spp. colonization of broilers

The main source for Campylobacter spp. transmission from the environment to broiler chickens is still unclear. One implicated reservoir for the organism has been untreated broiler drinking water. This study was conducted with broilers first using experimental conditions (isolation units) and second under commercial conditions. We compared the rate of intestinal colonization in chickens provided 2 to 5 parts per million (ppm) chlorinated drinking water in relation to the frequency of colonization in chickens given unsupplemented drinking water. No significant difference (P > 0.05) was detected in isolation frequency or level of Campylobacter spp. colonization in birds provided chlorinated drinking water and control birds provided water without supplemental chlorine. In the isolation unit experiments, 86.3% (69/80) of the control and 85.0% (68/80) of the treated birds were colonized at levels corresponding to an average of 10(5.2) and 10(5.1) log colony-forming units (cfu) Campylobacter spp./g of cecal contents, respectively. Additionally, two sets of paired 20,000 bird broiler houses, with and without chlorination (2-5 ppm chlorine), were monitored in a commercial field trial. Effectiveness of chlorination was judged by prevalence of Campylobacter spp. in fecal droppings (960 samples) taken from the flocks in treated and control houses. Birds from the control houses were 35.5% (175/493) Campylobacter spp. positive, while 45.8% (214/467) of the samples from the houses having chlorinated drinking water yielded the organism. Chlorination of flock drinking water at the levels tested in this study was not effective in decreasing colonization by Campylobacter spp. under commercial production practices presently used in the United States.

Cecal colonization of chicks by porcine strains of Campylobacter coli

Ten genotypically distinct strains of Campylobacter coli were isolated from a swine production facility. These porcine isolates were then orally inoculated into day-of-hatch leghorn chicks and were excellent colonizers of the chick cecum. Campylobacter coli recovered from inoculated chickens were genotypically identical to the challenge strain. The absence of host specificity suggests a possible movement of strains among swine, field animals and birds, and poultry houses.

DNA diversity of the wla gene cluster among serotype HS:19 and non-HS:19 Campylobacter jejuni strains

Campylobacter jejuni infection is an important trigger of Guillain-Barré syndrome (GBS), and serotype HS:19 strains are over-represented among GBS-associated isolates. Structures in C. jejuni lipooligosaccharide (LOS) resemble human gangliosides, suggesting that molecular mimicry could be important in triggering the neural injury. We assessed the genetic diversity among 36 C. jejuni serotype HS:19 and non-HS:19 strains by analysis of PCR-based restriction fragment length polymorphism (RFLP) patterns of 12 LOS biosynthesis-related genes (wla cluster). PCR amplification revealed that the size, order, and direction of each wla gene was identical among all strains tested. However, an additional ORF, located between wlaI and wlaK, was detected in 28 of the 36 isolates examined, and nucleotide sequence analysis revealed that the gene was identical to orfE in C. jejuni strain NCTC 11168. An inverted repeat motif was found downstream of the wlaI stop codon and upstream of the orfE stop codon, an organization allowing pairing of repeated sequences that could lead to deletion of the internal segment. Digestion of the PCR products with restriction endonuclease DdeI or AluI and cluster analysis of RFLP banding patterns showed that all HS:19 strains were closely related and distinct from non-HS:19 strains, consistent with earlier analyses, suggesting that HS:19 strains represent a highly clonal population. RFLP analysis of wla genes also may be useful for epidemiological studies.

Lectin typing of Campylobacter concisus

A total of 44 clinical isolates and the type strain of the putative pathogen Campylobacter concisus were grouped based on their reactions with plant lectins. The optimized lectin typing system used C. concisus strains proteolytically pretreated and subsequently typed by using a panel of four lectins. The system grouped all 45 strains into 13 lectin reaction patterns, leaving no strain untypeable due to autoagglutination. Lectin types were both stable and reproducible.

Impact of transport crate reuse and of catching and processing on Campylobacter and Salmonella contamination of broiler chickens

The influence of transport, catching, and processing on contamination of broiler chickens with Salmonella and Campylobacter was investigated. Transport crates were reused with high frequency and were often still contaminated with Salmonella and Campylobacter when they arrived at the farm despite the fact that they were washed at the factory, and thus they were a potential route of infection. These organisms contaminated the feathers of previously Campylobacter- and Salmonella-negative birds going to the processing plant and were isolated from processed carcasses, albeit at a low frequency. The Campylobacter types which were the predominant organisms on the live birds when they arrived at the processing plant were not necessarily the types that were most frequently isolated from processed carcasses. This finding may reflect cross-contamination that occurred during processing or differences in the tolerance of the strains to the hostile environments that the bacteria experienced. The process of catching and putting the birds in crates significantly increased the chance of contamination with Campylobacter (P < 0.001).

Direct polymerase chain reaction detection of Campylobacter spp. in poultry hatchery samples

A rapid, sensitive, and specific polymerase chain reaction (PCR) assay was developed for the direct detection of Campylobacter in environmental samples from hatcheries. PCR, with a set of primers specific for the Campylobacter flaA short variable region (SVR), detected the presence of Campylobacter in both fluff and eggshell samples; however, a determination of whether the organism was living or dead could not be made. Conventional cultural methods detected no Campylobacter from the same samples. An additional benefit of the direct PCR assay is it allows for the production of a product that can be sequenced to provide further epidemiologic information.

[A case of meningoencephalitis and spondylodiscitis caused by Campylobacter fetus subsp. fetus infection]

Campylobacter fetus subsp. fetus (C. fetus) is a gram-negative, curved, rod-shaped microaerophile, occasionally may cause meningitis or meningoencephalitis in humans. This report documents the case of 49-year-old man with lumbar spondylodiscitis and meningoencephalitis caused by C. fetus infection. On admission, the patient was delirious and severe inflammatory reactions were seen in his serum. Cerebrospinal fluid (CFS) revealed normal glucose concentration and moderate mononuclear leukocytosis. Campylobacter species, which was very difficult to be identified, was cultured from the blood and CSF. During his clinical course, the patient complained of severe back pain, and lumbar MRI showed low intensity in a T1-weighed image of the L4 and L5 vertebral bodies and high intensity in a T2-weighed image of the L4-5 disc. The patient was diagnosed with spondylodiscitis caused by C. fetus infection. Meningoencephalitis may have occurred as a secondary infection. Antibiotics were administered, and the patient's condition improved. To our knowledge, only a few cases of spondylodiscitis caused by C. fetus have been reported. A CSF glucose concentration in the normal range and mononuclear leukocytosis are atypical findings in patients with pyogenic meningitis. Therefore, neurologists must be fully aware of the possible symptoms and signs of C. fetus infection.

The dioxin crisis as experiment to determine poultry-related campylobacter enteritis

In June 1999, the dioxin crisis, caused by dioxin-contaminated feed components, exploded in Belgium, resulting in withdrawal of chicken and eggs from the market. Through the sentinel surveillance system, a decrease in Campylobacter infections during June 1999 was noticed. A model was generated with the reports from preceding years (1994 to 1998), and a prediction of the number of infections in 1999 was calculated. The model shows a significant decline (40%) in the number of infections, mainly because of the withdrawal of poultry. The use of a disaster as an epidemiologic tool offers a unique opportunity to observe exceptional changes in the occurrence of infections or other diseases.

Molecular characterisation of human campylobacteriosis in Northern Ireland: evidence of clonal stability

BACKGROUND

No study has compared Campylobacter isolates from a human source in Northern Ireland over an extended period of time.

AIM

To investigate the clonal stability of thermophilic campylobacters isolated from acute bacterial enteritis in Northern Ireland from 1992 to 1999.

METHODS

Human isolates (n=272), originating from faeces, were characterised at the sub-species level using enterobacterial repetitive intergenic consensus sequence (ERIC2)--random amplification of polymorphic DNA (RAPD) typing.

RESULTS

Thirteen genotypes were identified where three types, namely ERIC A, ERIC C and ERIC I, accounted for 28.3%, 14.3% and 13.6%, respectively. There were no significant associations (p>0.05) between sex, age groupings and year of isolation and ERIC2 genotype, with the exception of ERIC D, which showed a significant decline in isolation with time (p=0.019).

CONCLUSIONS

ERIC genotypes were stable over this period, except genotype C which was lost during this time. Previous molecular typing methods showed campylobacters to be heterogeneous but this study suggests that the local human Campylobacter population consists of several common and stable genotypes. This study has established a database of local ERIC2 genotypes. This methodology may allow the establishment of an all-island database of clinical campylobacters that would be valuable in reducing human campylobacteriosis in Ireland.

Prevalence of cytolethal distending toxin (cdt) genes and CDT production in Campylobacter spp. isolated from Danish broilers

The pathogenesis of campylobacter infection in man is largely unknown, although cytolethal distending toxin (CDT) has been incriminated as a virulence factor. However, little is known about the cdt genes in Campylobacter spp. isolated from broiler chickens. A total of 350 cloacal swabs was collected and tested by conventional culture and PCR. Of the 114 Campylobacter isolates obtained, 101 (88.6%) were identified as C. jejuni and 13 (11.4%) as C. coli by conventional methods. cdt genes were detected by PCR in all the isolates except one C. jejuni isolate. Cytotoxic effects were produced in a Vero cell line, by 100 of the C. jejuni isolates. In contrast, 10 C. coli isolates produced much lower levels of toxin and 3 produced no detectable toxin. These results confirm the common occurrence of campylobacter infection in chickens and indicate that cdt genes are commonly present in both C. jejuni and C. coli isolates from broilers, but that there are distinct differences in CDT production in these two closely related species.

Comparison of SmaI-defined genotypes of Campylobacter jejuni examined by KpnI: a population-based study

Pulsed-field gel electrophoresis (PFGE) was used to analyse 147 isolates collected in two regions of Quebec province (Estrie and Montreal) between March 1998 and Feb. 1999, to determine the utility of molecular strain typing for a population-based collection of Campylobacter jejuni and to compare directly the discriminatory power of SmaI and KpnI restriction digests. With a combination of epidemiological criteria including space and time plus molecular strain typing, 49% of isolates from Estrie and 39% of isolates from Montreal were identified as belonging to a putative cluster. For 41% of the cases, sources were either missing or explicitly unknown; the remaining sources were subject to recall bias. Thus, the evaluation of sporadic cases of campylobacter enteritis by descriptive clinical investigation alone is neither sensitive nor reliable for identifying sources of infection. In the PFGE analysis, KpnI digests provided appreciably greater discriminatory power than SmaI digests. When combining the PFGE analyses with basic epidemiological criteria, 30% of the putative SmaI clusters were inconsistent with the epidemiological criteria compared with 17% of the KpnI clusters. Among the 98 isolates assigned to clusters by SmaI, only 65% gave concordant results with KpnI. In contrast, among the 81 isolates assigned to clusters by KpnI, 92% gave concordant results with SmaI. Finally, clusters that were epidemiologically related to ingestion of raw milk and specific water sources correlated better with the typing results based on KpnI than SmaI. Thus, KpnI is the enzyme of choice for molecular epidemiology studies of C. jejuni. The combination of continuous epidemiological surveillance and molecular strain typing may be useful for identifying new sources and mechanisms of transmission for community-acquired C. jejuni infection andultimately for developing new approaches to prevention.

An optimised recovery method for thermophilic Campylobacter from liver

BACKGROUND

The past three decades have witnessed the rise of Campylobacter enteritis in man from virtual obscurity to notoriety, with present isolation rates superseding those of other enteric pathogens such as Salmonella spp. and Shigella spp. in most developed countries. Although campylobacters are not completely new to applied bacteriology, they have evaded traditional isolation techniques used for the isolation of pure cultures, apart from single isolations that were free from competing organisms. Offals, in particular liver have been described as both a source of campylobacters, as well as a route of transmission of this organism to human. Therefore, the aim of this study was to develop an optimum method for the recovery of Campylobacter spp. from porcine liver.

RESULTS

Four isolation techniques (methods A-D) were compared in a small pilot study for their ability to successfully recover campylobacters from freshly eviscerated porcine liver. The optimum isolation method involved direct swabbing of the liver tissues followed by plating onto Preston Selective medium, which was superior to methods involving mechanical disruption to liver tissues, including direct plating and enrichment methods, with and without blood. Consequently, any isolation method that involves disruption of liver tissue e.g. homogenisation or stomaching, is not suitable for the detection of campylobacters from liver and hence it is recommended that employment of a direct swabbing technique without mechanical disruption of tissues in combination with selective plating to optimally recover campylobacters from freshly eviscerated liver.

CONCLUSIONS

Employment of a direct swabbing technique in combination with selective plating allow Campylobacter spp. to be optimally recovered from freshly eviscerated liver and therefore this technique is recommended when examining liver for the presence of this organism.

Evaluation of a PCR/DNA probe colorimetric membrane assay for identification of Campylobacter spp. in human stool specimens

DNA was extracted from 50 human stool specimens using the QIAamp DNA stool minikit. PCR amplification was followed by post-PCR hybridization to DNA probes specific for the Campylobacter genus, Campylobacter jejuni, and Campylobacter coli in a colorimetric membrane assay. Thirty-two of 38 culture-positive specimens were PCR/DNA probe positive for C. jejuni. The assay is rapid and simple and can be applied to stool specimens for the detection of Campylobacter.

Genotypic and serotypic stability of Campylobacter jejuni strains during in vitro and in vivo passage

The stability of four typing methods and the sero- and genotypic stability of three Campylobacter jejuni strains were evaluated after subculturing 50 times in triplicate and after colonising mice for up to 26 days. The employed methods were Penner heat-stable serotyping; automated ribotyping (RiboPrinting) using HaeIII restriction enzyme; pulsed-field gel electrophoresis (PFGE) using SmaI, SalI and KpnI; and random amplified polymorphic DNA analysis (RAPD) using primers 1254, 1281 and HLWL85. No changes in any of the DNA profiles or in the reactions to heat-stable antigens were identified among these strains after the in vitro and in vivo passages. However, one isolate became untypeable with RAPD after passage in one of the mice. In addition, eleven other C. jejuni strains of four different serotypes were subcultured ten times to screen for instability. Neither of these showed instability using PFGE and serotyping. Furthermore, three of four strains previously identified as unstable, showed to consist of mixed cultures, which explains the reported profile changes. The results indicate that the applied typing methods are reliable and applicable for typing of Campylobacter isolates from different sources over time, and that many C. jejuni strains are genetically stable as tested by these methods.

Genome sequence-based fluorescent amplified fragment length polymorphism of Campylobacter jejuni, its relationship to serotyping, and its implications for epidemiological analysis

The published genome sequence of Campylobacter jejuni strain NCTC 11168 was used to model an accurate and highly reproducible fluorescent amplified fragment length polymorphism (FAFLP) analysis. Predicted and experimentally observed amplified fragments (AFs) generated with the primer pair HindIII+A and HhaI+A were compared. All but one of the 61 predicted AFs were reproducibly detected, and no unpredicted fragments were amplified. This FAFLP analysis was used to genotype 74 C. jejuni strains belonging to the nine heat-stable (HS) serotypes most prevalent in human disease in England and Wales. The 74 C. jejuni strains exhibited 60 FAFLP profiles, and cluster analysis of them yielded a radial tree showing genetic relationships between and within 13 major clusters. Some clusters were related, and others were unrelated, to a single HS serotype. For example, all strains belonging to serotypes HS6 and HS19 grouped into corresponding single genotypic clusters, while strains of serotypes HS11 and HS18 each grouped into two genotypic clusters. Strains of HS50, the most prevalent serotype infecting humans, were found both in one large (multiserotype) cluster complex and dispersed throughout the tree. The strain genotypes within each FAFLP cluster were characterized by a particular combination of AFs, and among the cluster there were additional differential AFs. Identification of such AFs could act as a search tool to look for potential associations with disease or animal hosts, when applied to large number of human isolates. Genome-sequence based FAFLP, thus, has the potential to establish a genetic database for epidemiological investigations of Campylobacter.

Distribution of Campylobacter spp. in selected U.S. poultry production and processing operations

A study was conducted of 32 broiler flocks on eight different farms, belonging to four major U.S. producers. The farms were studied over I complete calendar year. Overall, 28 (87.5%) of the flocks became Campylobacter positive, and only four (12.5%) remained negative throughout the 6- to 8-week rearing period. In the majority of flocks, sampled every 2 weeks throughout production, Campylobacter-positive fecal and cecal samples were not detected until 4 to 8 weeks of age. In only six of the flocks were environmental samples found to be positive before shedding of Campylobacter was detected in the birds. Even in some of the Campylobacter-negative flocks, contamination of the rearing environment was positive for Campylobacter but did not result in the birds subsequently excreting the organism. These findings are discussed in relation to U.S. husbandry practices and present uncertainty about sources of Campylobacter infection for poultry flocks. Birds were often transported to the processing plant in coops that were already contaminated with Campylobacter, and the organisms were sometimes found in samples of scald water and chill water. After chilling, the proportions of Campylobacter-positive carcasses from different producers ranged from 21.0 to 40.9%, which is lower than in other studies, and possible reasons are considered.

Bacterial genetic fingerprint: a reliable factor in the study of the epidemiology of human campylobacter enteritis?

The rate of human intestinal infections with more than a single Campylobacter strain was determined and the genetic variabilities of Campylobacter strains throughout an infection episode were investigated by means of pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR). For 48 and 49 of 50 patients, all isolates from one sample showed identical patterns by PFGE and ERIC-PCR, respectively. Throughout an infection episode in 47 of 52 patients, the PFGE fingerprints of the isolates remained stable, while in 1 patient two different species were observed and in 4 patients different patterns were observed. Therefore, ERIC-PCR proved less discriminative than PFGE. These findings suggest that human infection with more than one Campylobacter strain is rare and should not significantly impair epidemiologic analyses. However, changes in the genetic fingerprint throughout an infection should be considered in the assessment of epidemiologic studies of Campylobacter spp.

Lipopolysaccharides in the development of the Guillain-Barré syndrome and Miller Fisher syndrome forms of acute inflammatory peripheral neuropathies

Guillain-Barré syndrome (GBS), an acute inflammatory polyneuropathy, is preceded in most cases by an infectious illness, and Campylobacter jejuni, a leading cause of acute gastroenteritis, is the most common antecedent to GBS and its ocular variant, Miller Fisher syndrome (MFS). O (Penner) serotyping is considered to distinguish between C. jejuni strains based on differences in lipopolysaccharide (LPS) structure. Serotypes of C. jejuni uncommon in enteritis, such as serotype O:19 and O:41, have been associated with GBS. Chemical studies on the core oligosaccharide (OS) of C. jejuni LPSs from serotypes including O:1, O:2, O:4, O:10, O:19, O:23, O:36 and O:41 have revealed structures that mimic human gangliosides including GM1, GD1a, GD2, GD3, and GM2. Research has focused on the view that molecular mimicry may be a factor in the pathogenesis of GBS. Serum antibodies against gangliosides, particularly GM1 ganglioside, are present in 30% of GBS patients, and are highly associated with MFS, but are generally absent in enteritis cases uncomplicated by neuropathy. Collective data from human and animal studies with anti-ganglioside antibodies suggest a pathogenic role for the antibodies. Many aspects of the pathogenesis of GBS are unclear, in particular how LPS is presented to T cells or the role of host factors in disease development.

Molecular identification of Campylobacter concisus

A 1.6-kb DNA fragment isolated from a Campylobacter concisus genomic library gave C. concisus-specific restriction fragment length patterns when it was used as a probe in hybridization studies. All of the strains tested, including type strains and clinical isolates, contained a 0.5-kb HindIII fragment that hybridized to the probe. DNA sequencing of the 1.6-kb fragment identified three open reading frames (ORFs). One of the ORFs encodes the carboxy terminus of GyrB, and the translational products of ORF2 and ORF3 showed similarity to hypothetical proteins, previously identified in Campylobacter jejuni. DNA-DNA hybridization studies with a fragment internal to ORF3 showed that this sequence was responsible for the signal observed with the 0.5-kb HindIII fragment. A rapid PCR assay was developed and evaluated. Primers that annealed to the extremities of the 1.6-kb fragment were used to obtain an amplicon of the correct size from both reference and clinical strains of C. concisus.

Differentiation of Campylobacter species by AFLP fingerprinting

The fluorescent amplified fragment length polymorphism (AFLP) fingerprinting method was tested for its ability to identify and subtype the most important Campylobacter species found in veterinary infections. Sixty-nine reference strains and 19 clinical isolates of Campylobacter jejuni subsp. jejuni, Campylobacter jejuni subsp. doylei, Campylobacter upsaliensis, Campylobacter coli, Campylobacter lari, Campylobacter fetus subsp. fetus, C. fetus subsp. venerealis, Campylobacter hyointestinalis subsp. hyointestinalis, C. hyointestinalis subsp. lawsonii, Campylobacter mucosalis, Campylobacter helveticus and Campylobacter sputorum were subjected to analysis. The topology of the dendrogram obtained by numerical analysis of the AFLP profiles did not reflect the phylogenetic relationships as derived from 16S rDNA sequence comparison. However, except for C. lari, AFLP analysis grouped the strains that belonged to the same genomic species into distinct clusters. C. lari strains were separated into two distinct AFLP groups, which corresponded with nalidixic-acid-sensitive and -resistant variants of C. lari. These results correlated with data from whole-cell protein profiling. Within C. jejuni, C. hyointestinalis and C. fetus, strains could be identified at the subspecies level. AFLP analysis also allowed the subtyping of most species at the strain level. It is concluded that AFLP analysis is a valuable tool for concurrent identification of campylobacters at the species, subspecies and strain levels. In addition, the data confirm and extend previous reports showing that C. lari is a heterogeneous species that may comprise multiple taxa.