Zoonotic Public Health Hazards in Backyard Chickens

Backyard poultry has become increasingly popular in industrialized countries. In addition to keeping chickens for eggs and meat, owners often treat the birds as pets. However, several pathogenic enteric bacteria have the potential for zoonotic transmission from poultry to humans but very little is known about the occurrence of zoonotic pathogens in backyard flocks. The occurrence and the antimicrobial resistance of Salmonella enterica, Campylobacter spp., Listeria monocytogenes and enteropathogenic Yersinia spp. was studied in 51 voluntary backyard chicken farms in Finland during October 2012 and January 2013. Campylobacter isolates were further characterized by pulsed-field gel electrophoresis (PFGE), and the occurrence of ESBL/AmpC-producing E. coli was investigated. The findings from this study indicate that backyard chickens are a reservoir of Campylobacter jejuni strains and a potential source of C. jejuni infection for humans. Backyard chickens can also carry L. monocytogenes, although their role as a primary reservoir is questionable. Campylobacter coli, Yersinia pseudotuberculosis and Salmonella enterica were only found sporadically in the faecal and environmental samples of backyard poultry in Finland. No Yersinia enterocolitica carrying the virulence plasmid was isolated. All pathogens were highly susceptible to most of the antimicrobials studied. Only a few AmpC- and no ESBL-producing E. coli were found.

A foodborne outbreak due to Cryptosporidium parvum in Helsinki, November 2008

We report the first foodborne outbreak caused by Cryptosporidium parvum in Finland. The outbreak occurred among personnel of the Public Works Department in Helsinki, who had eaten in the same canteen. 72 persons fell ill with diarrhoea, none was hospitalised. Four faecal samples obtained from 12 ill persons were positive for Cryptosporidium by an antigen identification assay and microscopy. The vehicle of infection could not be identified with certainty but a salad mixture was suspected.

Evaluation of immunofluorescence microscopy and enzyme-linked immunosorbent assay in detection of Cryptosporidium and Giardia infections in asymptomatic dogs

The performance of immunofluorescence microscopy (IF) and enzyme-linked immunosorbent assay (ELISA) in canine feces was evaluated. IF and Cryptosporidium ELISA detected 10(5)oocysts/g, while the detection limit for Giardia ELISA was 10(4)cysts/g. The Cryptosporidium ELISA showed 94% specificity but only 71% sensitivity. The Giardia ELISA correlated well with IF (sensitivity 100%, specificity 96%) and was capable of detecting animal specific Giardia duodenalis genotypes. Visual interpretation appeared appropriate for assessment of ELISA results. The proportion of positive samples and possible zoonotic character of Cryptosporidium and Giardia infections in 150 asymptomatic Finnish dogs from the Helsinki area were studied. The overall proportion of dogs positive for Cryptosporidium was 5% (7/150) and that for Giardia 5% (8/150). In dogs < or =12 months old, the corresponding proportions were 17% and 19% (n=36). Sequence analyses of the 18S rDNA gene identified the isolates as Cryptosporidium canis and animal specific genotypes of G. duodenalis (assemblages C-E), indicating restricted risk of zoonotic transmission.

A large outbreak of campylobacteriosis associated with a municipal water supply in Finland

In August 1998, an outbreak of campylobacteriosis occurred in one municipality in northern Finland. A 10% random sample of residents (population 15 000) was selected through the National Population Registry for a survey conducted by using postal questionnaires. Cases were defined as residents of the municipality with onset of acute gastroenteritis from 1 to 20 August 1998. Of 1167 respondents (response rate 78%), 218 (18.7%) met the case definition. Drinking non-chlorinated municipal tap water was strongly associated with illness (OR 34.4). The estimated total number of ill persons was 2700. Campylobacter jejuni was isolated from stool samples of 45 (61%) out of 74 patients tested. All five isolates tested had indistinguishable PFGE patterns. Water samples were negative for campylobacter and coliforms. Epidemiological and environmental evidence suggested mains repair as the source of contamination. Non-chlorinated ground-water systems may be susceptible to contamination and can cause large outbreaks.

An outbreak of gastroenteritis from a non-chlorinated community water supply

STUDY OBJECTIVE

To determine the source and the extent of a community wide outbreak of gastroenteritis.

DESIGN

A matched case-control study with postal questionnaires. Subtyping of campylobacter strains by pulsed field gel electrophoresis (PFGE).

SETTING

A rural municipality with a population of 8600 in southern Finland, August 2000. Two thirds of the population receive non-chlorinated ground water from the municipal water supply.

PARTICIPANTS

Cases were randomly selected among residents of the municipality who contacted the municipal health centre because of gastroenteritis and had illness onset between 31 July and 20 August 2000. Community controls were identified from the population registry and matched according to sex, year of birth, and postal code.

MAIN RESULTS

Four hundred and sixty three persons contacted the municipal health centre because of gastroenteritis. Campylobacter jejuni was isolated from stool samples of 24 persons. One hundred and thirty seven cases and 388 controls were enrolled in the case-control study. In multivariate analysis, drinking unboiled water from the municipal supply was significantly associated with illness (odds ratio 11.1, 95% confidence interval 1.4 to 90.2). C jejuni was isolated from one tap water sample. The water isolate and all but one of the patient isolates were indistinguishable by PFGE.

CONCLUSIONS

Combining epidemiological investigation with molecular subtyping methods provided strong evidence that water was the source of the outbreak. Non-chlorinated small ground water systems may be susceptible to waterborne outbreaks and constitute a risk to rural populations.

Comparative analysis of Cryptosporidium, Giardia and indicator bacteria during sewage sludge hygienization in various composting processes

AIMS

To evaluate the suitability of Clostridium perfringens, Escherichia coli and enterococci as indicator organisms for Cryptosporidium and Giardia in treated sludge.

METHODS AND RESULTS

Occurrence of Cryptosporidium oocysts and Giardia cysts, detected and enumerated by direct immunofluorescence microscopy, were compared with counts of indicator bacteria during six different sewage sludge hygienization processes, including closed reactor and open windrow composting, and sludge sanitation by quicklime or peat addition. No statistical correlation existed between the counts of indicator bacteria, Cl. perfringens, E. coli, and enterococci and occurrence of Cryptosporidium or Giardia. In sludge end-products, Giardia cysts were detected more frequently than Cryptosporidium oocysts.

SIGNIFICANCE OF THE STUDY

Direct analysis is the best method to confirm the presence of (oo)cysts in sludge.

Evaluation of the purification capacity of nine portable, small-scale water purification devices

A test was performed to evaluate the microbial and chemical purification capacity of nine portable, small-scale water purification filter devices with production capacity less than 100 L/h. The devices were tested for simultaneous removal capacity of bacteria (cultured Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae and Enterobacter cloacae), enteric protozoans (formalin-stored Cryptosporidium parvum oocysts), viral markers (F-RNA bacteriophages) and microcystins produced by toxic cyanobacterial cultures. In general, the devices tested were able to remove bacterial contaminants by 3.6-6.9 log10 units from raw water. Those devices based only on filtration through pores 0.2-0.4 microm or larger failed in viral and chemical purification. Only one device, based on reverse osmosis, was capable of removing F-RNA phages at concentrations under the detection limit and microcystins by 2.5 log10. The present study emphasised the need for evaluation tests of water purification devices from the public safety and HACCP (Hazard Analysis and Critical Control Point) points of view. Simultaneous testing for various pathogenic/indicator microbes and microcystins was shown to be a useful and practical way to obtain essential data on actual purification capacity of commercial small-scale drinking-water filters.

Prevalence of campylobacters in chicken flocks during the summer of 1999 in Finland

In order to determine the prevalence of campylobacter positive broiler flocks in Finland, every flock from all three major slaughterhouses was studied during the period from 1 May to 30 September 1999. Caecal samples were taken in the slaughterhouses from five birds per flock. A total of 1132 broiler flocks were tested and 33 (2.9%) of those were campylobacter positive. Thirty-one isolates were C. jejuni and two isolates were C. coli. Isolates were serotyped for heat-stable antigens (Penner) and genotyped with pulsed-field gel electrophoresis (PFGE). The most common serotypes were serotypes 6, 7, 12 and 4-complex. Together with SmaI and KpnI patterns there were 18 different PFGE genotypes. Simultaneous monitoring of chicken flocks and typing of the isolates produced data which can be used to study the epidemiology of campylobacters in chicken as well as their role in human infections.

Simultaneous detection of Cryptosporidium parvum and Giardia in sewage sludge by IC-PCR

AIMS

The aim of this study was to develop a method based on immunomagnetic capture and polymerase chain reaction (IC-PCR assay) for detection of Cryptosporidium parvum and Giardia intestinalis in sewage sludge.

METHODS AND RESULTS

The detection limit of the IC-PCR assay for both organisms was 625 oocysts and cysts ml(-1). By hybridization of PCR products the sensitivity could be increased to 125 oocysts and cysts ml(-1). Forty-four sludge samples from 12 wastewater treatment plants were examined. The samples positive for Giardia (9 out of 44) were from eight wastewater plants and the C. parvum genotype 2 samples (3 out of 44) originated from different sewage works.

CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY

IC-PCR offers the possibility to distinguish between Cryptosporidium and Giardia genotypes. This assay can be used to monitor the presence of these organisms in a community and to determine contamination of sludge used as soil amendment.

Genomic relatedness within five common Finnish Campylobacter jejuni pulsed-field gel electrophoresis genotypes studied by amplified fragment length polymorphism analysis, ribotyping, and serotyping

Thirty-five Finnish Campylobacter jejuni strains with five SmaI/SacII pulsed-field gel electrophoresis (PFGE) genotypes selected among human and chicken isolates from 1997 and 1998 were used for comparison of their PFGE patterns, amplified fragment length polymorphism (AFLP) patterns, HaeIII ribotypes, and heat-stable (HS) serotypes. The discriminatory power of PFGE, AFLP, and ribotyping with HaeIII were shown to be at the same level for this selected set of strains, and these methods assigned the strains into the same groups. The PFGE and AFLP patterns within a genotype were highly similar, indicating genetic relatedness. The same HS serotypes were distributed among different genotypes, and different serotypes were identified within one genotype. HS serotype 12 was only associated with the combined genotype G1 (PFGE-AFLP-ribotype). These studies using polyphasic genotyping methods suggested that common Finnish C. jejuni genotypes form genetic lineages which colonize both humans and chickens.

A cultured strain of "Helicobacter heilmannii," a human gastric pathogen, identified as H. bizzozeronii: evidence for zoonotic potential of Helicobacter

We compared the characteristics of a cultured human "Helicobacter heilmannii" isolate with those of other helicobacters found in animals. Phenotypic, protein profile, 16S rDNA sequence, and DNA-DNA hybridization analyses identified the human strain as H. bizzozeronii, a species frequently found in dogs. Thus, H. bizzozeronii may have zoonotic potential.

Campylobacters: the most common bacterial enteropathogens in the Nordic countries

Campylobacters have been known as important human pathogens since the late 1970s. Campylobacter jejuni and coli are the most common bacterial enteropathogens in the developed countries. During the past years an increasing incidence of campylobacteriosis has been reported in many developed countries. C. jejuni is the most common Campylobacter species while C. coli accounts for about 5-10% of the cases. Although the genome of C. jejuni NCTC 11168 strain was sequenced recently, the exact pathogenetic mechanisms are still not known. Furthermore, there are no reliable animal models available. The epidemiology of this common infection is not well understood; however, eating and handling poultry, contaminated drinking water, and contact with pet animals have been recognized as important risk factors. Most of the cases are sporadic although large water-borne outbreaks have also been reported. Discriminatory typing methods are helpful in tracing the sources and transmission routes. In addition to traditional serotyping, genotyping methods, such as pulsed-field gel electrophoresis, have been developed. As Campylobacter infections probably precede Guillan-Barré syndrome in many cases, a great interest has lately been focused on the possible triggering mechanisms underlying this phenomenon.

A three-year study of Campylobacter jejuni genotypes in humans with domestically acquired infections and in chicken samples from the Helsinki area

Campylobacter jejuni isolates from stool samples of patients with domestically acquired sporadic infections and from chicken from retail shops were studied during seasonal peaks from June to September over a 3-year period from 1996 to 1998. A large number of pulsed-field gel electrophoresis (PFGE) genotypes (a combined SmaI-SacII pattern) were identified each year. Certain genotypes persisted for the whole study period, and predominant genotypes represented 28 to 52% of the strains during a restricted period of time. The peak level of positive chicken samples was between July and August of each study year, when 10 to 33% of the samples were positive for campylobacter. The same PFGE genotypes found in humans were also detected in the chicken samples. This suggests that common genotypes were circulating in the area.

Genetic diversity of atypical Aeromonas salmonicida studied by pulsed-field gel electrophoresis

Pulsed-field gel electrophoresis (PFGE) pattern analysis with XbaI restriction enzyme was used to study the genetic heterogeneity of 88 atypical Aeromonas salmonicida strains which were earlier or during this study characterized phenotypically, by ribotyping (ClaI/PstI) and by plasmid profile analysis. The strains of certain'ribotypes were also analysed by digestion with SpeI. The strains represented different geographic locations: Finland (72 strains), Iceland (5 strains), Norway (5 strains), Sweden (4 strains) and Denmark (2 strains), and they were from 17 fish species during 1981 97. Thirty-one PFGE genotypes found among these strains correlated well with the ribotypes, and in most cases PFGE pattern analysis subdivided ribotypes into several PFGE genotypes, and further within a PFGE genotype into subtypes. XbaI and SpeeI digests produced concordant results. In most cases, PFGE patterns of strains with the same ribotype shared many fragments, suggesting genetic relatedness. PFGE patterns of most Norwegian and Icelandic strains isolated during an approximately 10-year period had the same ribotype and their PFGE patterns shared most fragments, suggesting close genetic relatedness. Moreover, atypical strains of ribotypes B/B and H/H isolated from the same Finnish fish farms had closely related patterns suggesting genetic stability and persistence of these genotypes. Genotype 29 of Achromogenic strains was strongly associated with disease of Finnish arctic char and grayling. PFGE was shown to be a distinguishing method to study the genetic heterogeneity of atypical A. salmonicida. epidemiology of these infections.

Identification of hippurate-negative thermophilic campylobacters

Twenty-eight thermophilic campylobacter isolates showing negative hippurate hydrolysis were further characterized. Using Campylobacter jejuni and coli specific primers for ceuE gene, five of the isolates with repeatedly negative results in rapid hippurate hydrolysis were positive in C. jejuni-specific polymerase chain reaction (PCR) and 13 isolates were shown to be C. coli. All except one isolate with positive results in C. jejuni PCR were negative in C. coli PCR including those with repeatedly negative hippurate hydrolysis results. One isolate was positive in both PCRs due to a mixed culture. In comparison with PCR, API Campy gave concordant results in only 20 of the 28 isolates tested. Hybridization with PCR probes for ceuE gene of known C. jejuni and coli strains confirmed PCR results in all 27 isolates tested. In contrast to hippurate hydrolysis, PCR seemed to be a more reliable method to identify C. coli.

Stability of related human and chicken Campylobacter jejuni genotypes after passage through chick intestine studied by pulsed-field gel electrophoresis

The genomic stability of 12 Campylobacter jejuni strains consisting of two groups of human and chicken isolates was studied by analysis of their PFGE (pulsed-field gel electrophoresis) patterns after passage through newly hatched chicks' intestines. The patterns of SmaI, SalI, and SacII digests remained stable after intestinal passage, except for those of two strains. One originally human strain, FB 6371, changed its genotype from II/A (SmaI/SacII) to I/B. Another strain, BTI, originally isolated from a chicken, changed its genotype from I/B to a new genotype. The genomic instability of the strains was further confirmed by SalI digestion and ribotyping of the HaeIII digests. In addition, heat-stable serotype 57 of strain FB 6371 changed to serotype 27 in all isolates with new genotypes but remained unchanged in an isolate with the original genotype. Serotype 27 of strain BTI remained stable. Our study suggests that during intestinal colonization, genomic rearrangement, as demonstrated by changed PFGE and ribopatterns, may occur.

Evaluation of a molecular identification scheme based on 23S rRNA gene polymorphisms for differentiating canine and feline gastric Helicobacter spp

A scheme for the rapid identification of Helicobacter spp. using restriction fragment length polymorphism digestion profiles of PCR amplified 23S rRNA genes is described. The efficacy of this scheme for speciation of the closely related gastric species H. felis, H. bizzozeronii and H. salomonis was evaluated. It was difficult to distinguish between some RFLP profiles obtained and often, more than one profile was seen with each species examined. Some evidence was found that the 23S rRNA gene copies of these species may not be identical. Moreover, the identification scheme was ineffective in discriminating these species from each other, although they could be differentiated, as a group, from other Helicobacter spp. The results indicate that this scheme should be carefully evaluated with a number of isolates if it is to be applied to additional, highly related Helicobacter spp.

Characterization of Helicobacter felis by pulsed-field gel electrophoresis, plasmid profiling and ribotyping

BACKGROUND

Helicobacter felis, an organism naturally infecting both canine and feline gastric mucosa, has been largely used as in animal models to study the ecology and treatment of human Helicobacter pylori infections. H. felis has not yet been studied at the genetic level.

METHODS

The aims of this study were to modify an in situ DNA isolation method suitable for H. felis and, by the use of pulsed-field gel electrophoresis (PFGE), plasmid profiling, and ribotyping, to determine the degree of genetic variation among H. felis strains isolated from cats and dogs from various geographic locations, and to determine the genome size of H. felis. Furthermore, the ability of these new H. felis strains to colonize mice was tested.

RESULTS

Most H. felis strains were distinguishable from each other, and 20 distinct PFGE types were detected. Four pairs of strains within a country and animal species produced identical patterns. All strains tested were found to carry several plasmids and plasmid profiling was equally discriminatory to PFGE. Ribotyping was not able to discriminate all the strains.

CONCLUSIONS

The genome size of H. felis was found to be approximately 1.6 Mb.

Detection and effects of helicobacters in healthy dogs and dogs with signs of gastritis

OBJECTIVES

To determine prevalence, colonization density, and distribution of helicobacters and gastric histologic findings in healthy dogs and dogs with signs of gastritis; to evaluate association of colonization density and gastric inflammation; and to compare the number of Helicobacter spp with degree of inflammation.

DESIGN

Cross-sectional prevalence survey.

ANIMALS

25 healthy dogs and 21 dogs with signs of gastritis.

PROCEDURE

During endoscopy, gastric mucosal biopsy specimens were obtained from healthy and affected client-owned dogs. Histologic and cytologic evaluation and results of a urease test were used for detecting helicobacters, which were identified definitively by use of transmission electron microscopy and bacterial culture.

RESULTS

Helicobacters were detected in all 25 healthy and 20 of 21 affected dogs. Cytologic examination was a more sensitive method than histologic examination or the urease test. Helicobacters were found least frequently and in fewest number in the antrum in both groups of dogs. Gastric inflammation was evident in both groups of dogs and did not differ significantly between groups. A significant association was not detected between colonization density or the number of Helicobacter spp and degree of gastric inflammation. In both groups, H bizzozeronii, H felis, and H salomonis were cultured.

CLINICAL IMPLICATIONS

Histologically verified chronic gastritis is common in dogs with signs of gastritis as well as in healthy dogs. Colonization density of helicobacters was not associated with degree of gastric inflammation in the dogs of our study. It remains to be determined whether certain strains of Helicobacter spp can induce gastritis in dogs.

Mycoplasma contamination of canine gastric biopsy samples and cultures of gastric Helicobacter spp

Helicobacter felis and H. bizzozeronii are canine gastric helicobacters related to H. pylori. The growth of gastric helicobacters requires a complex medium including blood and serum. We found that some of our blood agar cultures were contaminated with mycoplasmas, which were isolated from one biopsy sample and several blood agar cultures of canine gastric helicobacters by PCR or culture method. However, none of our other 18 Helicobacter strains, subcultured 10-15 times since 1990, were found to be contaminated when studied in spring 1996. Nor was horse serum used as a growth supporter found to be contaminated with mycoplasmas. All our mycoplasma isolates grew as pure cultures and as cocultures with H. bizzozeronii on a selective medium containing vancomycin, polymyxin B and trimethoprim used in cultivation of helicobacters. Our data suggest that mycoplasmas occurring on biopsy samples can grow as contaminants on Helicobacter cultures.

Isolation and identification of Helicobacter spp. from canine and feline gastric mucosa

It is known that virtually all healthy adult dogs and cats harbor spiral helicobacters in their gastric mucosa. Three species, Helicobacter felis, Helicobacter bizzozeronii, and Helicobacter salomonis have been isolated in vitro from the gastric mucosa of these animals. The aims of this study were to evaluate the efficacy of an isolation method for canine and feline gastric helicobacters that has been developed at the University of Helsinki; to estimate the prevalence and distribution of these taxa in the samples examined; and to assess the efficacy and validity of an extensive set of standardized conventional phenotypic tests, whole-cell protein profiling, and ultrastructural analysis in identifying the different species isolated from canine and feline gastric mucosa. We cultured 95 and 22 gastric mucosal biopsies from dogs and cats, respectively. Twenty-one H. bizzozeronii strains, 8 H. felis strains, 8 H. salomonis strains, 3 mixed cultures, 2 "Flexispira rappini"-like organisms, and 3 as yet uncharacterized strains were isolated from the dogs, and 3 H. felis strains were isolated from the cats. The methods used here yielded Helicobacter isolation rates of 51% from dogs and 13.6% from cats, which exceed those reported previously. The main difficulties were primary isolation, mixed cultures, and identification to the species level. In the species identification, a detailed morphological examination was found to yield important phenotypic characteristics. A large panel of biochemical and tolerance tests did not clearly differentiate the closely related species H. bizzozeronii, H. felis, and H. salomonis. Highly standardized whole-cell protein profiling was shown to be an excellent method for species identification. Improvements in culture conditions for these bacteria are still needed, especially for cats. A genetic identification method not requiring culture is needed for future studies of these very fastidious helicobacters, as the clinical significance and ecology of these species within the gastric mucosa of the domestic carnivores remain largely unknown.

Detection of Helicobacter-like bacteria in porcine gastric biopsy samples by amplification of 16S rRNA, ureB, vacA and cagA genes by PCR

Preliminary evidence for the presence of Helicobacter-like bacteria was sought in 395 porcine gastric samples by a urease test. Of the samples, 37% (146/395) were urease-positive and 82% (82/100) of the Gram-stained urease-positive samples showed large, tightly spiralled organisms. Several methods were applied to culture the organisms but isolation was unsuccessful, contaminant organisms being considered to be one of the major problems. PCR with Helicobacter genus-specific primers for 16S rRNA and ureB genes, and primers for H. pylori vacA and cagA genes were tested with 102 ureasepositive biopsy samples. The PCR results showed some evidence for the presence of the urease and the vacA genes in porcine Helicobacter-like bacteria and raises the possibility of pathogenicity by these organisms.

Typing of human Campylobacter jejuni isolates in Finland by pulsed-field gel electrophoresis

A total of 69 pulsed-field gel electrophoresis (PFGE) types were identified among 176 Campylobacter jejuni isolates from Finnish patients. In two geographic areas studied, five predominant PFGE types comprised over 40% of the isolates. One-third of the isolates had unique PFGE types. In small outbreaks, identical PFGE patterns were demonstrated, indicating a common source of infection.

Transmission of canine gastric Helicobacter salomonis infection from dam to offspring and between puppies

H. bizzozeronii CCUG 35045, a new canine gastric Helicobacter spp. was used for experimental infection of four weaned puppies at 7 weeks of age. Controls were four nonchallenged puppies. The puppies originated from two dams which had Helicobacter salomonis infection in biopsy samples taken 3 weeks before the delivery but which had urease, brush cytology and culture-negative biopsy samples taken 7 weeks after antimicrobial treatment (metronidazole, amoxicillin, bismuth subcitrate). Both dams were detected urease- and Helicobacter-positive again three and a half months after therapy. Dam B was shown to be colonised with the similar genotype of H. salomonis for more than 2 years. Unexpectedly, H. salomonis was also cultured from gastric biopsy samples of the nonchallenged puppies three times during 7 months. When H. salomonis isolates of dams and puppies were studied by ribotyping (HaeIII, ClaI or PstI) they were shown to be identical although the HaeIII and PstI REA patterns of dam A differed from the patterns of dam B and nonchallenged group by one fragment. PFGE pattern analysis of NotI digests, however, revealed that the isolates of the puppies were identical with the isolates of dam B, and differed from the isolates of dam A. The isolates of the dams and puppies in the nonchallenged group were metronidazole-resistant. The antimicrobial therapy had merely suppressed, but not eradicated, the infection from dams. These studies suggested that puppies may acquire gastric Helicobacter infection from dams during the lactation period and puppies can infect each other during their early life. PFGE pattern analysis was shown to be a more distinguishing method than ribotyping to study the similarity of the isolates.

Water as a reservoir for Campylobacter jejuni infection in cows studied by serotyping and pulsed-field gel electrophoresis (PFGE)

The occurrence of campylobacters was studied in the faecal samples of a dairy herd with about 20 animals and in the lake which was their source of drinking water during the grazing period from June to September. Of the total of 141 faecal samples studied, 0-21% were found to be positive for C. jejuni at various sampling times throughout the year. More cows were found to be campylobacter-positive in summer or in autumn after the grazing period than after the winter, when the animals were inside and their drinking water source was municipal chlorinated tap water. C. jejuni was isolated from most of the lake water samples. Serotyping with heat stable antigens and molecular typing with PFGE using SacII- and SmaI-digested DNA revealed that an animal that was permanently infected with C. jejuni sero-/PFGE-type PEN 0:6, 25/I/ND most probably contaminated the lake water in summer 1987. This was the only sero/PFGE-type isolated from the lake water in summer and autumn 1987 and in spring 1988. This sero/PFGE-type was also isolated from four other cows in autumn 1987, suggesting that lake water was the source of the infection. This study is first to employ molecular methods to assess the possible role of contaminated drinking water in the transmission of campylobacter infection within a dairy herd.

Helicobacter salomonis sp. nov., a canine gastric Helicobacter sp. related to Helicobacter felis and Helicobacter bizzozeronii

During a study of the prevalence and distribution of gastric helicobacters in domestic pets, a novel group of Helicobacter-like organisms were identified. These "Helicobacter group 2" strains were initially distinguished from the species Helicobacter felis and Helicobacter bizzozeronii by their cellular morphology and the type of motility exhibited. Bacterial cells were only slightly spiral, 5 to 7 microns long, and 0.8 to 1.2 microns wide and showed an unusual slow wavelike motion. Each cell had tufts of sheathed flagella at one or both ends. Phylogenetic analysis by 16S ribosomal DNA sequence comparison revealed that H. felis, H. bizzozeronii, "Gastrospirillum hominis" 2, and the new group of helicobacters formed a distinct cluster with intraspecies similarity values of more than 98%. These taxa were clearly separated from all other known Helicobacter species. Dot blot DNA-DNA hybridization studies indicated that the Helicobacter group 2 strains are genetically homogeneous and distinct from other canine and feline gastric helicobacters. Quantitative DNA-DNA hybridization experiments showed that Helicobacter group 2 strains exhibit > 90% DNA homology to each other, but < 39% homology to the phylogenetically related taxa H. felis and H. bizzozeronii. We propose the name Helicobacter salomonis for the novel Helicobacter group 2 strains. The type strain is H. salomonis Inkinen (= CCUG 37845).

Morphological diversity of cultured canine gastric Helicobacter spp

The cell morphology, the number of flagella, the occurrence of periplasmic fibrils and ultrastructural structures of five groups of cultured canine gastric Helicobacter spp. were compared. The study included four strains of Helicobacter felis, four strains of Helicobacter bizzozeronii, one strain of 'Flexispira', six strains of an unnamed spiral organism 2 and one strain of an unnamed spiral organism 3 which were isolated from gastric biopsies. Cultures were studied with negative staining, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Bacterial dimensions were measured from the negative staining samples and values were tested with ANOVA and Bonferroni tests. The organisms studied differed from each other morphologically. H. felis was a slightly spiraled organism with periplasmic fibrils. 'Flexispira' was a thin and straight organism with periplasmic fibrils. H. bizzozeronii was a tightly spiraled organism. Spiral organism 2 was loosely spiraled and thicker than the other organisms. Spiral organism 3 was a short curved rod having a single bipolar flagellum. The other species had multiple flagella. As a conclusion the canine gastric Helicobacter spp. can be differentiated from each other morphologically with an electron microscope. The morphological differences were mainly found in the structures involved in motility. The importance of the differences may lie in their impact on the colonization in a gastric mucous environment.

Molecular and phenotypic methods for the characterization of atypical Aeromonas salmonicida

Atypical Aeromonas salmonicida form a taxonomically diverse group among the psychrophilic A. salmonicida. Characteristics of 53 atypical A. salmonicida strains originating from Finland, Denmark, Norway and Sweden were studied using 60 phenotypic tests. Ribopattern analysis and plasmid profiles were used as genetic methods. The production of brown pigment on the furunculosis agar containing L-tyrosine divided the atypical oxidase-positive strains into two groups: pigment-producing (n = 35) and achromogenic (n = 16). PstI differentiated all the atypical A. salmonicida from A. salmonicida subsp. salmonicida. Combined ribopatterns ClaI/PstI divided pigment producing atypical strains into four major groups B/B, G/G, G/T, F/F. Most of the achromogenic oxidase-positive strains belonged to two major groups H/H or U/U. Cluster analysis of ribopatterns and plasmid profile analysis also supported the division of atypical oxidase-positive A. salmonicida into pigment-producing and achromogenic groups. The oxidase-negative strains formed a distinct group which differed from oxidase-positive atypical A. salmonicida type biochemically and in terms of ribopatterns. Our results also support the use of ribopattern analysis as a valid method to study the epidemiology of infections caused by atypical A. salmonicida on fish farms.

Aeromonas species in fish, fish-eggs, shrimp and freshwater

Aeromonas spp. are common contaminants of fish and seafood. They also are ubiquitous in the water environment. Aeromonas spp. were identified in 27 (93%) of 29 fish, in 17 (100%) fish-egg, in two (16%) of 12 shrimp samples and in 23 (100%) freshwater samples. In total, 117 Aeromonas strains were isolated from 69 positive samples, several samples having had two or three Aeromonas species. Included in this were also 26 mesophilic Aeromonas strains isolated in association with the study on fish diseases. The distribution of the species into 13 known hybridization groups (HGs) were studied by phenotypic and molecular methods. Ribopattern analysis of SmaI digested DNA was used for the identification of HGs. The predominant HG in fish, fish-eggs and freshwater samples was A. hydrophila HG 3 because 63% (22/37), 28% (16/57) or 80% (16/20) of the strains, respectively, were in HG 3. A. hydrophila HG 2 was also common in fresh fish samples but was not identified in fish-egg samples. HG 7 was common in fish samples studied for fish diseases and in freshwater samples. Strains which were not allotted to any HGs were common (19 of 143 strains). A. hydrophila HG 1, A. caviae HG 4, A. veronii subspecies sobria or subspecies veronii HG 8/10 known to be associated with human diarrhea were uncommon in all samples. The three strains isolated from frozen shrimp during two suspected food-borne outbreaks were A. hydrophila HG 2 and HG 3.

Comparison of diagnostic methods for detecting gastric Helicobacter-like organisms in dogs and cats

Diagnostic methods for detecting gastric Helicobacter-like organisms (GHLOs) in dogs and cats were compared. Samples for brush cytology, the urease test and histological examination were collected post mortem from the fundus, corpus and antrum of 10 dogs (17 sample sites from each animal) and 10 cats (14 sample sites each). Samples of tissue from the fundus or corpus were taken for transmission electron microscopy and culture from three and eight dogs, respectively, and from six cats that gave a positive urease test with samples from these regions. In all dogs and in six of the 10 cats, GHLOs were detected by at least one of three methods (brush cytology, urease test or histological examination) in all regions. By brush cytology, GHLOs were demonstrated in all samples from the dogs and the positive cats. In cats, the urease test (60 min) gave a positive result in every sample site; in dogs it gave a positive result in 100% of the corpus samples, in 95% of the fundus samples and in 62% of the antral samples. Histological examination revealed GHLOs in all samples from the fundus and corpus of the dogs and of the positive cats; and in 74% and 91.7% of the antral samples of the dogs and cats, respectively. GHLOs were seen in all dogs and cats studied by transmission electron microscopy, and culture of gastric tissue was successful in 3/8 dogs and 1/6 cats. In this study, brush cytology was thus the most sensitive method for demonstrating GHLOs.

Occurrence and topographical mapping of gastric Helicobacter-like organisms and their association with histological changes in apparently healthy dogs and cats

The occurrence and topographical mapping of the gastric Helicobacter-like organisms (GHLOs) and their association with histological changes were studied in apparently healthy dogs and cats. Multiple samples were collected for histological examination from the fundus, corpus and antrum of the stomach of 10 dogs and 10 cats. Fundus and corpus were also sampled for transmission electron microscopy (three dogs, six cats), and for culture (eight dogs, six cats). In all dogs, GHLOs were detected in the fundus and corpus, and in the antrum of nine dogs, and significantly more often in the fundus and corpus (in all sample sites examined) than the antrum (P < 0.01). In cats, GHLOs were demonstrated in 6/10 individuals, and in all regions and sample sites. In dogs GHLOs were detected in all sample sites of the fundus and corpus. Lymphocytes, plasma cells and lymphocyte aggregates were found in all dogs in all regions; there were significantly more plasma cells in the antrum than in the corpus (P < 0.05). Neutrophils were found in six dogs, and eosinophils in seven dogs. In cats, lymphocyte aggregates were found only in GHLO-positive cats, which also had more lymphocytes in the fundus and corpus than GHLO-negative ones (P < 0.5). In dogs, no statistically significant association was found between the number of GHLOs and inflammatory parameters. Four dogs showed histological changes comparable to mild chronic gastritis and another six dogs to mild active chronic gastritis. Mild chronic gastritis was found in the antrum of all cats, and it occurred significantly more often in the antrum than in other regions (P < 0.01). In cats, there was a statistically significant association between GHLOs and chronic gastritis in the fundus and corpus (P < 0.05). GHLOs resembling human 'Helicobacter heilmannii' were identified in all the dogs and cats studied by electron microscopy, and Helicobacter felis in one dog in addition. Culture was successful in three dogs and one cat; 'H, heilmannii' was identified in two of the dogs, and H. felis in the third dog and the cat. GHLOs were found to be common in apparently health dogs and cats. Based on the results of this study, one sample from the fundus and corpus is enough to demonstrate GHLOs. In cats, GHLOs may cause histological changes comparable to chronic gastritis, but in dogs this association remain unclear. It is also questionable if the histological criteria for human gastritis, used in the present study, are suitable for dogs and cats.

Culture and characteristics of Helicobacter bizzozeronii, a new canine gastric Helicobacter sp

Organisms whose cells were large, tight spirals were isolated from gastric biopsies of dogs. Touch cytology samples from all of the dogs contained large spiral organisms. Characteristics of 10 strains are described. These organisms were 5 to 10 microns long by 0.3 microns wide, and each cell had 10 to 20 sheathed flagella at both ends of the cell. The cells did not have periplasmic fibrils. These organisms were microaerophilic and grew at 37 and 42 degrees C but not at 25 degrees C on brain heart infusion agar containing blood. They did not grow on brucella blood agar. They were catalase and oxidase positive, hydrolyzed urea but not hippurate, reduced nitrate, and were resistant to nalidixic acid but susceptible to cephalothin and metronidazole. In contrast to Helicobacter felis, they hydrolyzed indoxyl acetate. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles of all of the strains were similar, and the protein patterns of these organisms differed from those of other Helicobacter spp. Dot blot DNA-DNA hybridization experiments revealed that the new strains were closely related to each other but clearly different from H. felis, Helicobacter pylori, Helicobacter mustelae, and Campylobacter jejuni. The name Helicobacter bizzozeronii sp. nov. is proposed for these organisms. Our results suggest that other "uncultured" gastric helicobacters may be cultured if optimal culture conditions are found.

Distribution of Aeromonas phenospecies and genospecies among strains isolated from water, foods or from human clinical samples

A total of 332 Aeromonas spp. originating from drinking water (n = 75), fresh water (n = 57), chicken and ground beef (107), human faecal samples in association with travelling (n = 49), human faecal samples not associated with travelling (n = 38), and six strains from human blood cultures were studied by phenotypic methods and by using analysis of ribopatterns as a molecular method for the identification of the 13 known hybridization groups (HGs). Also included were the reference strains of each HG. A. hydrophila HG 1, A. caviae HG 4 and A. veronii biotype sobria HG 8/10 were the most important genospecies identified in human faecal samples. A. hydrophila HG 2 and A. media HG 5B predominated in drinking water and A. hydrophila HG 2 and HG 3, A. media HG 5A and HG 5B predominated in fresh water. In drinking water only one isolate was A. hydrophila HG 1 and two isolates were A. caviae HG 4. Clinically important Aeromonas spp. HG 1 (A. hydrophila), HG 4 (A. caviae) and HG 8/10 (A. veronii biotype sobria) were common in chicken and ground beef. In contrast to the drinking water samples, HG 5A was common in chicken and ground beef samples. Atypical, unidentified isolates were most often found in fresh water samples (12/57 strains). Although water has been suspected of being an important source of human aeromonas infections, clinically important HGs were found to be in the minority among Aeromonas spp. identified in drinking water or fresh water. The distribution of Aeromonas spp. HGs among drinking water, chicken and ground beef samples was also different, suggesting that contamination of meat or chicken may not originate from water.

Phenotypic and molecular characteristics of Aeromonas salmonicida subsp. salmonicida isolated in southern and northern Finland

Aeromonas salmonicida subsp. salmonicida causes outbreaks of furunculosis in salmonid fish. Furunculosis was first detected in Finland in 1986 on fish farms located on the Finnish coast of the Bothnian Bay. Molecular methods, SDS-PAGE, ribotyping, randomly amplified polymorphic DNA (RAPD) and plasmid profile analysis as well as phenotypic characteristics (biochemical characteristics, maximum growth temperature, pigment and elastase production) were used both for typing the strains and to study the possible routes of transmission of the organism to Finland and the spread of infection within Finland from 1986 to 1993. Ribopattern analysis of chromosomal DNA digested with SmaI, BglI, PstI and ClaI of 28 Finnish strains and eight foreign strains (Denmark, Sweden, Norway or Canada) showed that all Finnish strains and the Swedish strain originating from the Swedish coast of the Bothnian Bay had identical ribopatterns. All other foreign strains had distinct, unique ribotypes except for the second Swedish strain studied, the ribotype of which was identical with that of one Danish strain. RAPD typing, based on the results of two arbitrary primers, yielded 15 types for the Finnish strains. Except for both Danish strains, which had the RAPD type which was identical with that of one Finnish strain, the foreign strains had RAPD patterns differing from those of the Finnish strains. Plasmid profile typing and RAPD profile typing did not correlate. Ribotyping with four different enzymes proved to be the most sensitive method for studying genetically homogeneous Aer. salmonicida subsp. salmonicida. Ribopattern analysis showed that the infection which first started in 1984/1985 on the Swedish coast of the Bothnian Bay may have been transmitted to Finland where the first outbreaks occurred in 1986. The strains infecting Finnish fish farms were very homogeneous, with most differences seen, for example, in maximum growth temperature, plasmid profiles and the RAPD profiles of the strains.

Maximum growth temperature ranges of Aeromonas Spp. isolated from clinical or environmental sources

Only a limited number of phenotypic tests are available for the differentiation of all 13 known hybridization groups (HG) of Aeromonas spp. These organisms have a wide spectrum of warm-blooded and cold-blooded hosts. In the present study, the maximum growth temperatures (tmax) of the most common HGs of Aeromonas spp. originating from human fecal samples, food, water, and healthy and diseased fish were determined with a plate-type continuous temperature-gradient incubator. We observed that determination of the tmax can be applied for differentiation of HG 1 from HG 2 and 3 (phenospecies A. hydrophila); HG 6 from HG 4, 5A, and 5B (phenospecies A. caviae); HG 7 from HG 8/10 (phenospecies A. sobria); and HG 11 from HG 8/10 (phenospecies A. veronii). HG 1, 4, 8/10, and 13 strains occurring also in human clinical samples had a high tmax, about 40°C or higher. Hybridization group 2, 3, 5A, and 5B strains, which in most cases originated from water or food, had tmax values in the range of about 36-39°C, while HG 6, 7, and 11 had tmax values in the range of about 33-37°C. Fish pathogenic strains of A. salmonicida subsp. salmonicida and subsp. achromogenes had the lowest tmax values from about 30 to 35°C.

Association of Aeromonas spp. with travellers' diarrhoea in Finland

The association of Aeromonas spp. with travellers' diarrhoea was studied among 978 Finnish tourists travelling to Morocco in winter (n = 398) and autumn (n = 580) in 1989. Fifty-five isolates from diarrhoeal patients with (n = 16) or without (n = 39) a recent travelling history in a developing country were also included. In Morocco, Aeromonas spp. were isolated from 8.7% of patients with diarrhoea and from 1.4% of non-diarrhoeal tourists (p < 0.001). Aeromonas spp. were found as the sole pathogen in 5.5% of patients (p < 0.001). Diarrhoea with multiple pathogens, including Aeromonas spp., was found in 3.1% of patients. Species identification by phenotypic and genotypic methods indicated that A. veronii biotype sobria (hybridisation group HG 8/10) and A. caviae (HG 4) were the most common Aeromonas spp. associated with travellers' diarrhoea. A. hydrophila (HG 1) and A. caviae (HG 4) were common in patients acquiring diarrhoea in Finland. Ribotyping of strains within a species showed that all strains had different ribotypes although the tourists were infected during the same trip. This study suggested that only certain Aeromonas spp. were commonly found in travellers' diarrhoea. However, the causative role of those species is unclear.

Chronic diarrhea due to a single strain of Aeromonas caviae

Over a period of 17 months, Aeromonas caviae was cultured 15 times as the sole enteropathogen from the feces of a man who had developed chronic diarrhea after traveling to Turkey. Determination of rRNA gene restriction patterns confirmed that the seven isolates of Aeromonas caviae studied were identical (hybridization group [HG]4). After therapy with ciprofloxacin for four weeks, the patient was culture negative for the original isolate, and six months later a novel strain of Aeromonas media with a different ribopattern (HG 5A) was isolated from the feces of the patient. The patient responded again, both clinically and bacteriologically, to a four-week course of ciprofloxacin and has remained asymptomatic since then.

Occurrence of Aeromonas spp. in samples of ground meat and chicken

Aeromonas spp. was commonly isolated from ground meat and chicken samples at the retail level. The dominant species in ground meat were A. hydrophila and A. caviae. In chicken, A. sobria was common while A. caviae was isolated infrequently. Although A. hydrophila was isolated from 75% of ground meat samples and 62% of chicken samples, DL-lactate-positive A. hydrophila (genospecies 1) was isolated from only 25 or 37% or respective samples. Sorbitol-positive A. hydrophila (genospecies 3) was common in both ground meat and chicken.

Sensitivity of Helicobacter pylori to different bile salts

The sensitivity of Helicobacter pylori to different unconjugated or conjugated bile acids both on BHI blood agar and in BHI broth supplemented with starch, horse serum or egg yolk was studied. Bile salts were more toxic in the medium containing starch than in the media containing horse serum or egg yolk, and unconjugated bile salts were more toxic than the conjugated salts. Deoxycholic acid was the most toxic of the bile acids studied. Ox bile was bacteriostatic at the 2% level. Bile Salts 3 mixture was bactericidal at a concentration of 0.25 mmol.

Bismuth subsalicylate in the prevention of colonization of infant mice with Campylobacter jejuni

Infant mice were used for the evaluation of the efficacy of bismuth subsalicylate (BSS) in the prevention of the growth of Campylobacter jejuni in the intestine. The MIC90 of ten C. jejuni strains was 900 micrograms/ml. Of three dosage regimens tested, continuous treatment before and after the bacterial challenge, mimicking the way BSS is used in the prevention of traveller's diarrhoea, was the most effective. Growth inhibition was dose dependent; the high dose of 2000 micrograms per day was more effective than 300 micrograms per day. After cessation of treatment, campylobacter counts increased to the same level as in the control animals.

Effect of endotoxin on colonisation of Campylobacter jejuni in infant mice

An infant mouse model has been used to investigate the colonisation of the intestine by Campylobacter jejuni and the effect of endotoxin (Escherichia coli O26: B6) on the initial stage of this process. Endotoxin injected 1 or 16 h before the bacterial challenge had no effect on the growth of campylobacters but endotoxin injected 4 to 10 h before the bacterial challenge caused a bacteriostatic effect on the growth of campylobacters which lasted for one day. The bacteriostatic effect was evident both in the small intestine and in the distal part of the intestine containing caecum and colon. The mechanism of the bacteriostatic effect of endotoxin could not be explained in the study, but is thought to be non-immunological because it developed so rapidly. Oral and parenteral iron administered as ammonium ferric citrate or iron dextran, respectively, were used in an attempt to reverse the bacteriostatic effect. High oral doses of iron (0.5 mg per animal) were effective but small doses (0.5 mg per animal) were ineffective. Parenteral iron administration had a delayed effect on the reversal of the bacteriostatic effect of endotoxin. Transferrin administered orally caused a clear bacteriostatic effect in both endotoxin pretreated and untreated mice. Campylobacter counts were always lower in the small intestine than in the large intestine both in control and in endotoxin pretreated mice. This indicates that the large intestine is the primary ecological niche where campylobacters colonise mice.

Rapid method for the detection of DNase of campylobacters

A rapid agar diffusion method for the detection of DNase production of Campylobacter jejuni, C. coli, and C. pylori was developed. A strong pink zone indicating DNA hydrolysis was seen around the wells after 20 to 24 h of aerobic incubation at 37 degrees C. Pretreatment of cells with polymyxin B, which releases the cell-associated DNase, both shortened the time needed to read positive results to 8 h and increased the zone size.

The occurrence of thermophilic Campylobacter in mink and an experimental oral infection of pregnant mink by Campylobacter jejuni

The occurrence of C. jejuni in the intestinal contents of mink and in the mink feed, prepared from fresh, untreated slaughter offal, was studied. The farms and the central feeding kichens, from where the intestinal and feed samples were collected, were situated in the northwestern part of Finland. All mink samples, originating from 9 farms, and feed samples, originating from 2 central feeding kichens were negative for C. jejuni and for C. coll The only positive faecal samples were obtained from a farm, being located in the southern part of Finland.

Experimental colonization of C jejuni was followed in 10 pregnant mink during their last trimester of pregnancy. The animals colonized only transiently with C. jejuni. Five of the animals shedded Campylobacters only for 1–2 weeks after inoculation. Two experimental animals aborted. These animals were colonized at the time of abortion with C jejuni. The association of C jejuni infection to abortion was not, however, confirmed. The uterine contents or the fetuses examined were negative for Campylobacters.

Effect of various gas atmospheres on the growth and survival of Campylobacter jejuni on beef

Pieces of fresh beef were inoculated with three strains of Campylobacter jejuni. The meat was then allocated to three treatments: (a) vacuum packaged, (b) packaged in an atmosphere of 20% CO2 + 80% N2, and (c) packaged into sterile Petri dishes in anaerobic cultivation boxes, which were filled with a gas mixture of 5% O2 + 10% CO2 + 85% N2. The packaging material in the first two treatments was PA 80/PE 100-PE 100/PA 80/PE 100. The survival of Campylobacter cells was followed at 37 degrees C, 20 degrees C and 4 degrees C for 48 h, 4 days and 25 days, respectively. At 37 degrees C the counts of two Campylobacter strains increased in each package treatment for 48 h. At 20 degrees C and at 4 degrees C the counts of the same two strains decreased by 1 to 2 log units and 0.5 to 1 log unit, respectively, during storage. The survival of the two strains was about the same in all package treatments. The third strain was the most sensitive of the strains studied. At 37 degrees C its numbers increased only in the optimal gas atmosphere; at 20 degrees C the strain was not detectable after 24 to 48 h storage and at 4 degrees C after 4 days storage. The aerobic plate counts were determined for all samples at the same time as Campylobacter counts. The high indigenous bacterial numbers of the meat samples did not appear to have a great effect on the survival or growth of campylobacters.

Growth and survival characteristics of Campylobacter jejuni in liquid egg

Growth and survival of four Campylobacter jejuni strains in yolk, in liquid whole egg and in white during aerobic storage at 37, 20 and 4 degrees C was followed. In 48 h at 37 degrees C the cell counts of C. jejuni increased by about 3 log10 units in yolk and 1.60-3.35(10) log units in liquid whole egg. The growth of C. jejuni was slightly better in yolk than in liquid whole egg. At 20 degrees C during 48 h the cell counts decreased by about 0.5-1.5 log10 units in yolk and in liquid whole egg. At 4 degrees C the decrease in cell counts after 21 days ranged from 1 to 2 log10 units, except for one strain, KH3, which could not be detected after 14 days storage in yolk. In liquid whole egg the cell counts of this strain also decreased considerably during storage. In white the number of inoculated C. jejuni cells decreased rapidly. The killing effect of white was shown to be temperature-dependent; at 37 and 20 degrees C no positive samples were detected after 24 h and at 4 degrees C no positive samples were found after 48 h.

Characterization of Campylobacter jejuni/coli isolated from different sources

Characteristics of 50 strains of G. jejuni/coli isolated from rectal swabs, caecal contents or bile of cow, sheep, goat, swine, broiler chicken and man were investigated. All the strains grew at 30 °C, 35°C 42°C, but not at 25 °C. The strains were nalidixic acid sensitive. Differences were noticed in salt-tolerance, in the growth with 2,3,5 tri-phenyltetracolium chloride and in the hippurate hydrolysis. Growth of the strains with certain bile salts was also investigated and the results are discussed.