Serotyping of Campylobacter jejuni, Campylobacter coli, and Campylobacter laridis from domestic and wild animals

By using 50 unabsorbed antisera, we were able to serotype 272 (65.7%) of 414 thermotolerant campylobacters from wild and domestic animals, on the basis of heat-stable antigens identified by means of passive hemagglutination. Forty-two serotypes were recognized. The pattern of serotypes detected in the various animal species was compared to human clinical isolates by using the Czekanowski index (proportional similarity index). The highest degree of similarity to the clinical isolates was observed for the poultry isolates, followed by strains from wild birds, flies, and pigs (in order of decreasing similarity). The serotypes recovered most frequently from poultry (LAU 1 and LAU 2) were also most prevalent in Norwegian patients. In contrast, serotype LAU 35/44, the predominant porcine serotype, was never recovered from human clinical specimens. Flies captured in chicken farms and in piggeries harbored serotypes which were also commonly seen in chickens and pigs, respectively. Nine of the strains included in this study could not be ascribed to any defined species. All of these were resistant to nalidixic acid and did not produce H2S.     

Diversity of serotypes of Campylobacter jejuni and Campylobacter coli isolated in laboratory animals

One hundred nineteen isolates of Campylobacter jejuni and Campylobacter coli from nine laboratory animal species were serotyped using antisera to 20 Penner serotypes commonly isolated from cases of human enteric infections. Although C. jejuni and C. coli were isolated from laboratory animals with diarrhea, the majority were cultured from asymptomatic animals (81%). Seven of twenty-two isolates from animals with diarrhea were serotype 4 (32%) and three were serotype 1 (14%). Sixty-one of the 119 isolates (51%) were typeable using the 20 Penner antisera indicating that many of the isolates obtained from 29 nonhuman primates (five species), 20 ferrets, 7 hamsters, 15 cats and 48 dogs are serotypes commonly associated with human enteritis. Among typeable strains, 13 different serotypes were identified. Two particular serotypes, 4 and 19 were isolated from several species of animals and comprised 24% of the isolates studied. Since asymptomatic laboratory animals of several different species harbor serotypes of C. jejuni and C. coli that are potentially pathogenic to man, appropriate precautions should be instituted to minimize exposure of personnel to the organisms in laboratory animal feces. If suspected cases of zoonotic-related enteric campylobacteriosis involving laboratory animals do occur, serotyping of isolates would be a useful epidemiologic marker in studying the outbreak.     

Seropathotypes, Phylogroups, Stx subtypes, and intimin types of wildlife-carried, shiga toxin-producing escherichia coli strains with the same characteristics as human-pathogenic isolates

The objectives of this study were to investigate the presence of Shiga toxin-producing Escherichia coli (STEC) strains in wildlife that have spread in Europe, living near human settlements; to analyze their epidemiological role in maintenance and transmission to domestic livestock; and to assess the potential health risk of wildlife-carried strains. STEC strains were recovered from 53% of roe deer, 8.4% of wild boars, and 1.9% of foxes sampled in the northwest of Spain (Galicia). Of the 40 serotypes identified, 21 were classified as seropathotypes associated with human disease, accounting for 81.5% of the wildlife-carried STEC strains, including the enterohemorrhagic serotypes O157:H7-D-eae-γ1, O26:[H11]-B1-eae-β1, O121:H19-B1-eae-ε1, and O145:[H28]-D-eae-γ1. None of the wildlife-carried strains belonged to the highly pathogenic serotype O104:H4-B1 from the recent Germany outbreak. Forty percent of wildlife-carried STEC strains shared serotypes, phylogroups, intimin types, and Stx profiles with isolates from human patients from the same geographic area. Furthermore, wildlife-carried strains belonging to serotypes O5:HNM-A, O26:[H11]-B1, O76:H19-B1, O145:[H28]-D, O146:H21-B1, and O157:H7-D showed pulsed-field gel electrophoresis (PFGE) profiles with >85% similarity to human-pathogenic STEC strains. We also found a high level of similarity among STEC strains of serotypes O5:HNM-A, O26:[H11]-B1, and O145:HNM-D of bovine (feces and beef) and wildlife origins. Interestingly, O146:H21-B1, the second most frequently detected serotype in this study, is commonly associated with human diarrhea and isolated from beef and vegetables sold in Galicia. Importantly, at least 3 STEC isolates from foxes (O5:HNM-A-eae-β1, O98:[H21]-B1-eae-ζ1, and O146:[H21]-B1) showed characteristics similar to those of human STEC strains. In conclusion, roe deer, wild boar, and fox in Galicia are confirmed to be carriers of STEC strains potentially pathogenic for humans and seem to play an important role in the maintenance of STEC.     

Differences in the population structure of invasive Streptococcus suis strains isolated from pigs and from humans in The Netherlands

Streptococcus suis serotype 2 is the main cause of zoonotic S. suis infection despite the fact that other serotypes are frequently isolated from diseased pigs. Studies comparing concurrent invasive human and pig isolates from a single geographical location are lacking. We compared the population structures of invasive S. suis strains isolated between 1986 and 2008 from human patients (N?=?24) and from pigs with invasive disease (N?=?124) in The Netherlands by serotyping and multi locus sequence typing (MLST). Fifty-six percent of pig isolates were of serotype 9 belonging to 15 clonal complexes (CCs) or singleton sequence types (ST). In contrast, all human isolates were of serotype 2 and belonged to two non-overlapping clonal complexes CC1 (58%) and CC20 (42%). The proportion of serotype 2 isolates among S. suis strains isolated from humans was significantly higher than among strains isolated from pigs (24/24 vs. 29/124; P<0.0001). This difference remained significant when only strains within CC1 and CC20 were considered (24/24 vs. 27/37,P?=?0.004). The Simpson diversity index of the S. suis population isolated from humans (0.598) was smaller than of the population isolated from pigs (0.765, P?=?0.05) indicating that the S. suis population isolated from infected pigs was more diverse than the S. suis population isolated from human patients. S. suis serotype 2 strains of CC20 were all negative in a PCR for detection of genes encoding extracellular protein factor (EF) variants. These data indicate that the polysaccharide capsule is an important correlate of human S. suis infection, irrespective of the ST and EF encoding gene type of S. suis strains.     

A polymerase chain reaction (PCR) assay specific for Streptococcus suis based on the gene encoding the glutamate dehydrogenase

Polymerase chain reaction (PCR) primers that flank a 688-bp segment within the glutamate dehydrogenase gene (gdh) of Streptococcus suis type 2 could amplify efficiently the DNA of all 306 (100%) clinical S. suis isolates tested (pigs, n=305; human, n=1) encompassing all serotypes obtained from diverse organs, and geographic origins. When DNA from other bacteria were used as templates for amplification, no product was detected indicating specificity of the primers. Multiplex PCR was developed using the gdh gene primer pair and primers that targeted the gene encoding S. suis capsular biosynthesis (cps). This strategy enabled the detection of strains belonging to serotypes 1/2, 1, 2, 7, and 9, respectively. Using the multiplex-PCR technique, 12 out of 14 (86%) isolates that were previously identified as non-typable S. suis (based on biochemical reactions and serology) gave positive PCR results of which four were positive for serotype 7, three for serotype 2, and five for S. suis strains that belong to other serotypes. Retest results of all 14 isolates by several veterinary laboratories were identical with PCR and confirmed that the two non-PCR reactive isolates belonged to strains of other streptococcal species. These results indicated that PCR improved species determination and can thus be used as a reliable species-specific molecular diagnostic reagent for the accurate identification of S. suis isolates and a serotype-specific method for the detection of strains of serotypes 1/2, 1, 2, 7, and 9, respectively. The PCR method therefore has potential clinical and epidemiological applications.     

Genetic relatedness among Campylobacter jejuni serotyped isolates of diverse origin as determined by numerical analysis of amplified fragment length polymorphism (AFLP) profiles

AIMS: To use amplified fragment length polymorphism (AFLP) analysis to evaluate the genetic relatedness among 254 Campylobacter jejuni reference and field strains of diverse origin representing all defined 'Penner' serotypes for this species. METHODS AND RESULTS: Field strains (n = 207) from human diarrhoea and diverse animal and environmental sources were collected mainly through a National surveillance programme in Denmark and serotyped by use of the established 'Penner' scheme. Genetic relationships among these isolates, and the archetypal serotype reference strains, were assessed by numerical analysis of AFLP profiles derived from genomic DNA. Extensive genetic diversity was seen among the strains examined; however, 43 groups of isolates were identified at the 92% similarity (S-) level. Thirteen groups contained isolates from a single host, possibly representing genotypes of 'low risk' to human health. The remaining 30 groups contained isolates from humans, chickens and associated food products, cattle, sheep, turkeys, ostriches and/or dogs. Strains assigned to serotypes 2, 6/7, 11 and 12 formed major clusters at the 77.6% S-level. Most other serotypes did not form homogeneous clusters. CONCLUSIONS: High-resolution genotyping applied to strains from a comprehensive range of sources provides evidence for multiple sources of sporadic C. jejuni infection. The results suggest that public health protection measures should be directed at all foods of animal origin. SIGNIFICANCE AND IMPACT OF THE STUDY: The genetic relatedness among all 'Penner' serotypes of C. jejuni is assessed by AFLP analysis. In addition, further evidence of epidemic and host-specific clones of C. jejuni is provided.     

Serotypes, antimicrobial susceptibility, and gyr A gene mutation of Campylobacter jejuni isolates from humans and chickens in Thailand

In Thailand, 51% (36/70) Campylobacter jejuni isolates from humans and 68% (47/69) isolates from poultry were classified into 10 Penner serotypes (serotype B, C, R, E, G, A, K, D, I, and L) and 9 serotypes (serotype A, C, I, K, B, E, S, D, and L), respectively. The rate of antimicrobial drug resistance to nalidixic acid, ciprofloxacin, ampicillin, tetracycline, and erythromycin shown by human isolates were 96%, 96%, 29%, 57%, and 14%, while that shown by poultry isolates were 77%, 77%, 22%, 26%, and 17%, respectively. All quinolone-resistant strains contained a mutation in the gyrA gene (T(86)-->I(86)), suggesting that the strains were already widespread in Thailand.     

Diversities and similarities in PFGE profiles of Campylobacter jejuni isolated from migrating birds and humans

AIMS: To genetically sub-type Campylobacter jejuni strains isolated from migratory birds, and to compare these with clinical strains collected in the same area and corresponding time period, with the aim to increase our knowledge on sub-types occurring among wild birds and their possible impact on human disease. METHODS AND RESULTS: We sub-typed C. jejuni strains from migrating birds (n = 89) and humans (n = 47), using macrorestriction profiling by pulsed-field gel electrophoresis. Isolates from migrant birds often exhibited sub-types with higher levels of similarity to isolates from birds of the same species or feeding guild, than to isolates from other groups of birds. Likewise, could the vast majority of sub-types found among the migrant bird isolates not be identified among sub-types from human cases. Only two bird strains, one from a starling (Sturnus vulgaris) and one from a blackbird (Turdus merula), had sub-types that were similar to some of the human strain sub-types. CONCLUSIONS: Isolates from one bird species, or feeding guild, often exhibited high similarities, indicating a common transmission source for individuals, or an association between certain sub-types of C. jejuni and certain ecological guilds or phylogenetic groups of birds. Sub-types occurring among wild birds were in general distinctively different from those observed in patients. The two bird isolates that were similar to human strains were isolated from bird species that often live in close associations with human settlements. SIGNIFICANCE AND IMPACT OF STUDY: Wild birds have often been mentioned as a potential route for transmission of C. jejuni to humans. Our study demonstrates that strains isolated from birds most often are different from clinical strains, but that some strain similarities occur, notably in birds strongly associated with human activities.     

Molecular epidemiology of clinical and environmental isolates of the Cryptococcus neoformans species complex reveals a high genetic diversity and the presence of the molecular type VGII mating type a in Colombia

The aim of this study was to investigate the epidemiological relationships of clinical and environmental isolates of the Cryptococcus neoformans species complex in Colombia. The current study reflects data from 1987 to 2004. In Colombia serotypes A and B are most frequently recovered from patients and the environment. Of the 178 clinical isolates studied, 91.1% were of serotype A, 8.4% serotype B and 0.5% serotype C. Of the 247 environmental isolates, 44.2% were of serotype A, 42.6% serotype B and 13.2% serotype C. No serotype D isolates were isolated. Serotype AD has not been recovered in Colombia. PCR fingerprinting with the primers M13, (GACA)4 and (GTG)5 and URA5 gene restriction fragment length polymorphism analysis grouped the majority of clinical serotype A and environmental serotype B isolates into the molecular types VNI (98.1%) and VGII (100%), respectively. Mating type alpha was determined in 99.3% of serotype A isolates, but 96.6% of serotype B isolates were of mating type a. Similar profiles between clinical and environmental isolates suggest that the patients may have acquired the infection from the environment. The data presented form part of the Colombian contribution to the ongoing global survey of the C. neoformans species complex.     

Relatedness of Listeria monocytogenes Isolates recovered from selected ready-to-eat foods and listeriosis patients in the United States

Pulsed-field gel electrophoresis and serotyping were performed for 544 isolates of Listeria monocytogenes, including 502 isolates recovered from contaminated samples from 31,705 retail ready-to-eat (RTE) food products and 42 isolates recovered from human cases of listeriosis. The isolates were from Maryland (294 isolates) and California (250 isolates) and were collected in 2000 and 2001. The isolates were placed into 16 AscI pulsogroups (level of relatedness within each group, > or =66%), 139 AscI pulsotypes (levels of relatedness, > or =25% to 100%), and eight serotypes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 4b, 4c, and 4d). The most frequently found pulsotypes belonged to either pulsogroup A (150 food isolates plus 4 clinical isolates) or pulsogroup B (104 food isolates plus 5 clinical isolates). The majority of the 502 food isolates were either serotype 1/2a (298 isolates) or serotype 1/2b (133 isolates), whereas the majority of the 42 clinical isolates were either serotype 1/2a (19 isolates) or serotype 4b (15 isolates). Additionally, 13 clinical isolates displayed pulsotypes also found in food isolates, whereas the remaining 29 clinical isolates displayed 24 unique pulsotypes. These data indicate that most (86%) of the L. monocytogenes subtypes found in the RTE foods sampled belonged to only two serotypes and that 90% of the isolates displayed 73 pulsotypes, with 107 isolates displaying pulsotype 1. These data should help define the distribution and relatedness of isolates found in RTE foods in comparison with isolates that cause listeriosis.     

Relatedness of Listeria monocytogenes Isolates Recovered from Selected Ready-To-Eat Foods and Listeriosis Patients in the United States

Pulsed-field gel electrophoresis and serotyping were performed for 544 isolates of Listeria monocytogenes, including 502 isolates recovered from contaminated samples from 31,705 retail ready-to-eat (RTE) food products and 42 isolates recovered from human cases of listeriosis. The isolates were from Maryland (294 isolates) and California (250 isolates) and were collected in 2000 and 2001. The isolates were placed into 16 AscI pulsogroups (level of relatedness within each group, ≥66%), 139 AscI pulsotypes (levels of relatedness, ≥25% to 100%), and eight serotypes (serotypes 1/2a, 1/2b, 1/2c, 3a, 3b, 4b, 4c, and 4d). The most frequently found pulsotypes belonged to either pulsogroup A (150 food isolates plus 4 clinical isolates) or pulsogroup B (104 food isolates plus 5 clinical isolates). The majority of the 502 food isolates were either serotype 1/2a (298 isolates) or serotype 1/2b (133 isolates), whereas the majority of the 42 clinical isolates were either serotype 1/2a (19 isolates) or serotype 4b (15 isolates). Additionally, 13 clinical isolates displayed pulsotypes also found in food isolates, whereas the remaining 29 clinical isolates displayed 24 unique pulsotypes. These data indicate that most (86%) of the L. monocytogenes subtypes found in the RTE foods sampled belonged to only two serotypes and that 90% of the isolates displayed 73 pulsotypes, with 107 isolates displaying pulsotype 1. These data should help define the distribution and relatedness of isolates found in RTE foods in comparison with isolates that cause listeriosis.     

Serotypes, virulence genes, and PFGE patterns of enteropathogenic Escherichia coli isolated from Cuban pigs with diarrhea.

Thirty-six enteropathogenic Escherichia coli strains isolated from Cuban pigs with diarrhea were serotyped and screened by PCR for the presence of virulence genes. The 36 isolates belonged to 11 O serogroups and 14 O:H serotypes, with 53% of the isolates belonging to only two serotypes: O141:H- (13 isolates) and O157:H19 (6 isolates). Genes coding for STb, STa, VT2e, and LT toxins were identified in 69, 61, 53, and 6% of the isolates, respectively. The most prevalent fimbrial adhesin was F18, detected in 22 (61%) isolates. The gene encoding F6 (P987) colonization factor was identified in three (8%) isolates. None of the 36 isolates assayed contained genes encoding F4 (K88), F5 (K99), or F41. The seropathotype O141:H-:STa/STb/VT2e/F18 (13 isolates) was the most frequently detected, followed by O157:H19:VT2e/F18 (5 isolates). A genetic diversity study, carried out by pulsed-field gel electrophoresis (PFGE) of 24 representative isolates, revealed 21 distinct restriction patterns clustered in 18 groups (I-XVIII). Isolates of the same serotype were placed together in a dendrogram, but isolates of serotype O157:H19 showed a high degree of polymorphism. The results of this study demonstrate the presence in Cuba of different clusters among one of the most prevalent serotypes isolated from pigs with diarrhea. Further experiments are needed to determine whether some of these clusters have appeared recently; if so, their evolution, as well as their possible association with pathogenicity in farms should be studied.     

Studies on Swine Enteroviruses

Of 38 new isolates of enterovirus recovered from fecal specimens of Japanese pigs, 14 isolates were found to be strains of a new serotype (represented by strain IPI) distinct from the five serotypes of swine enterovirus hitherto recognized in Japan. The remaining isolates included serotypes Teschen, T80, SF1 and V13. The two different types of cytopathic effect, which have been recently recognized in swine kidney cell cultures, were also observed with our isolates; type I is characterized by a rounding of cells followed by aggregation and destruction of affected cells, and type II by granulation and degradation of cells with poor clumping of affected cells. Of interest is the finding that the type I strains possess a higher heat stability than the type II strains when heated at 50 C for one hr.     

A retrospective overview of enterovirus infection diagnosis and molecular epidemiology in the public hospitals of Marseille, France (1985-2005)

Human enteroviruses (HEV) are frequent human pathogens and, associated in particular with large outbreaks of aseptic meningitis. Here, we have compiled a database of clinical HEV isolates from the Public Hospitals of Marseille, from 1985 to 2005. Amongst 654 isolates that could be characterized by complete sequencing of the VP1 gene, 98% belonged to species HEV-B; the most frequently isolated serotypes were Echovirus E30, E11, E7, E6 and E4. The high incidence of E30 and the recent emergence of E13 are consistent with reports worldwide and peak HEV isolation occurred mostly in the late spring and summer months. The proportion of echoviruses has decreased across the years, while that of coxsackieviruses has increased. Stool (the most frequent sample type) allowed detection of all identified serotypes. MRC5 (Human lung fibroblasts) cell line was the most conducive cell line for HEV isolation (84.9% of 10 most common serotype isolates, 96.3% in association with BGM (Buffalo green monkey kidney cells)). Previous seroneutralization-based serotype identification demonstrated 55.4% accuracy when compared with molecular VP1 analysis. Our analysis of a large number of clinical strains over 20 years reinforced the validity of VP1 serotyping and showed that comparative p-distance scores can be coupled with phylogenetic analysis to provide non-ambiguous serotype identification. Phylogenetic analysis in the VP1, 2C and 3D regions also provided evidence for recombination events amongst clinical isolates. In particular, it identified isolates with dissimilar VP1 but almost identical nonstructural regions.     

Comparison of OspA Serotypes for Borrelia burgdorferi Sensu Lato from Japan,Europe and North America

Sixty-one Borrelia burgdorferi sensu lato strains from various sources (ticks, human, and wild animals) in Japan and two strains from ticks in Far Eastern Russia were classified on the basis of reactivity with 16 monoclonal antibodies (mAb) to outer surface protein A (OspA) and by DNA-DNA hybridization assay. Eleven OspA serotypes (J1 to J11) were recognized among the Japanese and the Far East Russian isolates (serotypes J1 to J9 were identified as B. garinii, serotype J10 was identified as B. afzelii, and serotype J11 corresponded to B. japonica), whereas 7 OspA serotypes for North American and European isolates previously reported (Bettina Wilske et al, J. Clin. Microbiol. 31:340-350, 1993) were not observed except for OspA serotype 2 which showed identical reactivity with OspA serotype J10. This finding provides helpful information for understanding the geographical distribution of Lyme disease borrelia and the development of vaccine and diagnostic tests. In conclusion: 1. B. burgdorferi sensu stricto has not been observed in Japan, 2. Japanese B. afzelii isolates are closely related to those from Europe, 3. B. garinii isolates from Japan are highly heterogeneous and apparently different from European B. garinii isolates.     

Molecular,serological, and virulence characteristics of Vibrio parahaemolyticus isolated from environmental,food, and clinical sources in North America and Asia

Potential virulence attributes, serotypes, and ribotypes were determined for 178 pathogenic Vibrio parahaemolyticus isolates from clinical, environmental, and food sources on the Pacific, Atlantic, and Gulf Coasts of the United States and from clinical sources in Asia. The food and environmental isolates were generally from oysters, and they were defined as being pathogenic by using DNA probes to detect the presence of the thermostable direct hemolysin (tdh) gene. The clinical isolates from the United States were generally associated with oyster consumption, and most were obtained from outbreaks in Washington, Texas, and New York. Multiplex PCR was used to confirm the species identification and the presence of tdh and to test for the tdh-related hemolysin trh. Most of the environmental, food, and clinical isolates from the United States were positive for tdh, trh, and urease production. Outbreak-associated isolates from Texas, New York, and Asia were predominantly serotype O3:K6 and possessed only tdh. A total of 27 serotypes and 28 ribogroups were identified among the isolates, but the patterns of strain distribution differed between the serotypes and ribogroups. All but one of the O3:K6 isolates from Texas were in a different ribogroup from the O3:K6 isolates from New York or Asia. The O3:K6 serotype was not detected in any of the environmental and food isolates from the United States, and none of the food or environmental isolates belonged to any of the three ribogroups that contained all of the O3:K6 and related clinical isolates. The combination of serotyping and ribotyping showed that the Pacific Coast V. parahaemolyticus population appeared to be distinct from that of either the Atlantic Coast or Gulf Coast. The fact that certain serotypes and ribotypes contained both clinical and environmental isolates while many others contained only environmental isolates implies that certain serotypes or ribotypes are more relevant for human disease.     

Prevalence of serologic types of Pasteurella multocida from 57 species of birds and mammals in the United States

The serologic types of 265 isolates of Pasteurella multocida collected from 50 species of wild birds and seven species of wild mammals over a 22-yr period were determined with the gel diffusion precipitin test. Antigens prepared from these isolates reacted with reference P. multocida antisera representing serotypes 1, 2, 3, 4, 5, 6, 7, 8, 12, and 15. Antigens from some isolates reacted slightly with antisera from more than one serotype. Overall, gel precipitin reactions involving serotype 1 (65%) and 3 (20%) were the most prevalent.     

Phenotypic diversity of Campylobacter isolates from sporadic cases of human enteritis in the UK

AIMS: The aim of this study was to identify and subtype a large collection of isolates of Campylobacter spp. to quantify diversity among strains causing human disease from geographically diverse sources in the United Kingdom. METHODS AND RESULTS: Isolates were characterized by the Penner serotyping scheme, Preston phage typing and biotyping methods. The diversity index calculated from the combined results of all three methods was 0.997 and indicated that isolates from sporadic cases of infection are very diverse. Strong associations between common phagetypes (PG52, PG121 and PG55) and the three most common serotypes (HS1, HS2 and HS4) found in the study were evident. CONCLUSIONS: Strains of C. jejuni causing human infections in the United Kingdom are very phenotypically diverse. Individual strains characterized by serotype, phagetype and biotype were detected throughout the 7-month study period and from geographically distinct sources, indicating an unrecognized outbreak or other epidemiologically significant source of human infection. SIGNIFICANCE AND IMPACT OF THE STUDY: The low frequency incidence of most C. jejuni strains should enable easy recognition of outbreaks by strain type surveillance at local, regional and national level in the United Kingdom. The characterization of common strain profiles in this study by simple phenotypic methods could provide the basis for strain specific epidemiological studies for reservoirs of infection and transmission routes for human infection.     

Restriction fragment length polymorphism analysis of the flaA gene of Campylobacter jejuni for subtyping human, animal and poultry isolates

233 strains of Campylobacter jejuni were subtyped by PCR-RFLP analysis of the flagellin (flaA) gene by double digestion with EcoRI and PstI (EP flaA-profiling). The strains represented a variety of common Penner heat stable (HS) serotypes and comprised isolates of human, bovine, ovine, chicken and canine origin. FlaA amplicons were obtained directly from DNA in cell lysates of most strains. RFLP analysis showed considerable allelic variation and nine EP flaA-types were identified of which the most common were type 2 (32%), type 3 (20%), type 4 (12%) and type 6 (12%). Other flaA-profiles each represented less than 10% of strains. C. jejuni strains of each serotype generally had one or two specifically associated flaA-types although some were features of several serotypes. Strains with the same flaA-type were found in different hosts. EP flaA-profiles were reproducible, clear and simple to record, and laboratory protocols were rapid and low cost with high throughput capacity. The EP flaA-profiling scheme provided an excellent molecular subtyping method to supplement HS serotyping, and reference strains are recommended to facilitate its use in future epidemiological investigations.     

Enterotoxigenicity and frequency of Campylobacter jejuni, C. coli and C. laridis in human and animal stool isolates from different countries

Campylobacter jejuni and C. coli strains were collected during three different years from adult patients with enterocolitis in Sweden (n = 372) from 49 patients in Kuwait, and Campylobacter strains from hens from Mexico, Pakistan and Sweden (n = 107) and Swedish pigs (n = 47). C. jejuni was the predominant species in human and hen isolates, and C. coli in pigs C. coli was significantly more common in human isolates from Sweden, and more common in hen isolates from Pakistan, than in hens from Sweden and Mexico. C. laridis was only isolated from pigs (17%) and was in no case enterotoxigenic. Both in human and hen isolates, C. jejuni strains were more enterotoxigenic than C. coli strains. C. jejuni strains from Swedish hens were less enterotoxigenic than those from Pakistan and Mexico (P less than 0.001), and strains from pigs were less enterotoxigenic than those from hens (P less than 0.001). We conclude that C. jejuni are more often enterotoxigenic and possibly more virulent than c. coli and C. laridis. The relative frequency of C. jejuni and C. coli in humans and animals differs from one country to another.