Identification and Epidemiological Typing of Campylobacter hyointestinalis Subspecies by Phenotypic and Genotypic Methods and Description of Novel Subgroups

Development of a multiplex PCR assay for identification of Campylobacter coli, Campylobacter fetus, Campylobacter hyointestinalis subsp. hyointestinalis, Campylobacter jejuni, Campylobacter lari and Campylobacter upsaliensis

A multiplex PCR assay has been developed for the identification of the six common Campylobacter taxa associated with human gastroenteritis and/or septicaemia, namely Campylobacter coli, Campylobacter fetus, Campylobacter hyointestinalis subsp. hyointestinalis, Campylobacter jejuni, Campylobacter lari and Campylobacter upsaliensis. The assay was developed using a combination of newly designed and published primers. It provided a specific PCR product for each of the five Campylobacter species and the one subspecies, and each of the PCR products was sufficiently distinguished by a difference in size by agarose gel electrophoresis. On evaluation of efficacy with 142 Campylobacter strains, the assay correctly identified all strains as 1 of the 6 Campylobacter taxa. This multiplex PCR assay is a rapid, simple and practical tool for identification of the six Campylobacter taxa commonly associated with gastroenteritis and/or septicaemia in humans, and offers an effective alternative to conventional biochemical-based assays.

Avian reservoirs and zoonotic potential of the emerging human pathogen Helicobacter canadensis

A polyphasic identification approach was used to investigate the taxonomic position of Campylobacter-like isolates recovered from barnacle geese (Branta leucopsis) and Canada geese (Branta candensis). Seven strains were selected from a collection of 21 isolates and analyzed by extensive phenotypic testing; four strains were characterized by 16S rRNA gene sequence analysis. The results clearly identified the bird isolates as Helicobacter canadensis, recently described as an emerging human pathogen. This is the first report of an animal reservoir for this organism and of its presence in Europe and confirms the zoonotic potential of H. canadensis.

Molecular typing of Campylobacter jejuni isolates involved in a neonatal outbreak indicates nosocomial transmission

Genotypic typing by restriction fragment length polymorphism and pulsed-field gel electrophoresis showed that two neonates in a neonatal ward were infected with the same Campylobacter jejuni strain. Isolates from the mother and brother of the index patient were identical to each other but distinct from the neonatal type. Genotyping results therefore suggested that the neonatal C. jejuni infection was nosocomial in origin.

Campylobacter jejuni in black-headed gulls (Larus ridibundus): prevalence, genotypes, and influence on C. jejuni epidemiology

Campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. We investigated the prevalence of Campylobacter jejuni subsp. jejuni in black-headed gulls (Larus ridibundus) in southern Sweden with the aim of examining the nature of C. jejuni infection in this bird species. Birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). Longitudinally sampled C. jejuni isolates from individual gulls were subjected to macrorestriction profiling (MRP) by pulsed-field gel electrophoresis to investigate the genotypical stability during the natural course of infection. Furthermore, a subset (n = 76) of black-headed gull isolates was compared to isolates from broiler chickens (n = 38) and humans (n = 56) originating from the same geographic area. We found a pronounced seasonal variation in C. jejuni carriage, with the highest rates found in late autumn. MRP similarities were higher between isolates of human and broiler chicken origin, than between those of wild bird origin and either of the other two hosts. However, identical MRPs were found in two gull isolates and one human isolate after digestion with two restriction enzymes, strongly indicating that they may have been colonized by the same clone of C. jejuni. The MRPs most prevalent in gull isolates did not occur among isolates from humans and broiler chickens, suggesting the existence of a subpopulation of C. jejuni adapted to species-specific colonization or environmental survival.

Transmission of Campylobacter hyointestinalis from a pig to a human

We report on a case of human gastroenteritis caused by the pathogen Campylobacter hyointestinalis. Recurrent watery diarrhea and intermittent vomiting were the most significant symptoms of the previously healthy patient. Whole-cell protein electrophoresis and 16S rRNA gene sequencing were used to identify this Campylobacter species. Investigation of the patient's surroundings led to the recovery of a second C. hyointestinalis strain originating from porcine feces. Subsequent typing of the human and the porcine isolates by pulsed-field gel electrophoresis revealed similar macrorestriction profiles, indicating transmission of this pathogen.

Campylobacter hyointestinalis subsp. hyointestinalis, a common Campylobacter species in reindeer

AIMS

To study the prevalence of Campylobacter spp. in the faecal material of reindeer, and to identify the isolates by means of a polyphasic approach. In addition, to study the genetic diversity of Camp. hyointestinalis subsp. hyointestinalis reindeer isolates by pulsed-field gel electrophoresis (PFGE).

METHODS AND RESULTS

The material, collected during the slaughter period in autumn 1998, comprised 399 faecal contents from the reindeer (Rangifer tarandus), a semi-domesticated, meat-producing ruminant of northern Finland. These samples came from 16 herds in the areas of eight reindeer slaughterhouses. Samples were cultured by methods suitable for isolation of fastidious Campylobacter species. Of all samples, 6% (24/399) were Campylobacter-positive. Phenotypic characteristics, SDS-PAGE protein patterns, dot blot DNA-DNA hybridization, 23S rDNA restriction fragment polymorphism analysis and PFGE identified the isolates as Camp. hyointestinalis subsp. hyointestinalis.

CONCLUSIONS

Campylobacter hyointestinalis subsp. hyointestinalis was the only Campylobacter species isolated from reindeer in this study. The isolates showed high genomic diversity in PFGE with the restriction enzymes SmaI and KpnI.

SIGNIFICANCE AND IMPACT OF THE STUDY

PFGE analysis is a useful subtyping method for epidemiological studies. Contaminated reindeer meat can be a source for human infections.

Genetic heterogeneity of Campylobacter concisus determined by pulsed field gel electrophoresis-based macrorestriction profiling

In order to investigate the genetic diversity of Campylobacter concisus to assist molecular typing studies, the use of macrorestriction profiling was examined. A suitable protocol was developed that included the use of formaldehyde pretreatment to prevent DNA degradation, and restriction enzyme NotI for pulsed field gel electrophoresis-based genotyping. Subsequently, 53 strains of C. concisus, principally from cases of diarrhoea in children, were examined. Fifty-one distinct patterns were obtained, indicating the high discriminatory potential of the method. Patterns comprised between one and 14 restriction fragments, with type and reference strains of two well-defined genomospecies of oral and faecal origin containing six and 12 fragments respectively. Our results show that C. concisus is genetically diverse and suggest the species as currently defined to be a taxonomic continuum comprised of several genomospecies. The pulsed field gel electrophoresis typing method described here has considerable potential for molecular epidemiological studies of C. concisus and may be a useful adjunctive method for helping to resolve key taxonomic issues for this species.

Rapid pulsed-field gel electrophoresis protocol for subtyping of Campylobacter jejuni

We developed a rapid pulsed-field gel electrophoresis (PFGE) protocol for subtyping Campylobacter isolates based on the standardized protocols used by PulseNet laboratories for the subtyping of other food-borne bacterial pathogens. Various combinations of buffers, reagents, reaction conditions (e.g., cell suspension concentration, lysis time, lysis temperature, and restriction enzyme concentration), and electrophoretic parameters were evaluated in an effort to devise a protocol that is simple, rapid, and robust. PFGE analysis of Campylobacter isolates can be completed in 24 to 30 h using this protocol, whereas the most widely used current protocols require 3 to 4 days to complete. Comparison of PFGE patterns obtained in six laboratories showed that subtyping results obtained using this protocol are highly reproducible.

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.

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.

Isolation and characterization of Campylobacter jejuni subsp. jejuni from macaroni penguins (Eudyptes chrysolophus) in the subantarctic region

On Bird Island, South Georgia, albatrosses (n = 140), penguins (n = 100), and fur seals (n = 206) were sampled for Campylobacter jejuni. C. jejuni subsp. jejuni was recovered from three macaroni penguins (Eudyptes chrysolophus). These isolates, the first reported for the subantarctic region, showed low genetic diversity and high similarity to Northern Hemisphere C. jejuni isolates, possibly suggesting recent introduction to the area.

An outbreak of infectious hepatitis in commercially reared ostriches associated with Campylobacter coli and Campylobacter jejuni

A disease causing high morbidity and mortality was observed in young ostriches from six properties in southeast Queensland, Australia. The disease affected birds from 2-8 weeks of age and was characterised clinically by bright-green urates and pathologically by severe necrotic hepatitis. The liver lesions resembled those of vibrionic hepatitis in other avian species. Campylobacter coli was isolated from the livers of affected ostriches from five of the six properties. Campylobacter jejuni subsp. jejuni was isolated from birds from the remaining property. Pulsed-field gel electrophoresis-based (PFGE) typing of representative isolates indicated that trade of infected birds between farms was an important factor in the spread of C. coli. Phenotypic and genotypic data suggest a clonal variant of the principal outbreak type may account for the remaining cases from which C. coli was found. Conventional biochemical test results and PFGE clearly distinguished the C. jejuni strain isolated from the geographically remote farm from the outbreak of C. coli type. We believe this to be the first definitive report of avian hepatitis associated with C. coli.

Water-borne Campylobacter jejuni infection in a Danish town---a 6-week continuous source outbreak

OBJECTIVE: To determine the cause and characteristics of illness of a Campylobacter jejuni outbreak in Denmark in 1995--96. METHODS: A retrospective follow-up study was designed for culture-confirmed cases and for residents without a bacteriologic diagnosis. Stored clinical and environmental isolates were analyzed by serotyping and genotyping with restriction endonuclease analysis (REA), pulsed-field gel electrophoresis (PFGE) and ribotyping. RESULTS: Campylobacter jejuni was isolated from 110 residents and visitors to the area. However, an estimate based on a telephone survey indicated that some 2400 people were affected by the outbreak. Water samples obtained from the community waterworks contained Campylobacter jejuni serotype O2, the same serotype as in all but one of the 30 stored isolates from the outbreak. The water and clinical isolates also showed the same DNA profile, except for the single strain showing the distinct serotype. The contamination of the water supply was traced back to contamination of ground water due to a break in a sewage pipe. CONCLUSIONS: A retrospective and demographic epidemiologic investigation of both culture-confirmed and non-culture-confirmed cases in the town combined with typing of the isolates was crucial in defining the extent and cause of the outbreak.