Yersinia enterocolitica and related species isolated from wildlife in New York State.

Fecal specimens for Yersinia screening were obtained from a variety of wild mammals, birds, reptiles, fish, and invertebrates throughout New York State. One specimen from each of 1,426 animals was examined. A total of 148 isolates of Yersinia enterocolitica and related species were obtained from 133 (9.3%) of the animals. Y. enterocolitica was isolated from 100 (7%) of the animals tested, including 81 (10%) of 812 mammals and 19 (3.3%) of 573 birds. Y. intermedia, Y. frederiksenii, and Y. kristensenii were isolated from 39 (2.7%), 5 (0.35%), and 4 (0.28%) animals, respectively. The 81 Y. enterocolitica isolates from mammals belonged to 15 serogroups and included three pathogens: two isolates of typical serogroup 0:8, the "American strain," one from a gray fox (Urocyon cinereoargenteus) and one from a porcupine (Erethizon dorsatum); and one isolate of serogroup 0:3, bacteriophage type IXb, the "Canadian strain," from a gray fox. The most prevalent serogroups recovered from mammals were 0:6,31 (16 isolates) and 0:5,27 (6 isolates). The 19 isolates of Y. enterocolitica from birds belonged to nine serogroups and included one serogroup 0:6,31 isolate from a common grackle (Quiscalus quiscula) and two serogroup 0:5,27 isolates from great horned owls (Bubo virginianus).     

Transmission of Yersinia enterocolitica 4/O:3 to pets via contaminated pork

AIMS: This study was conducted to investigate sources of Yersinia enterocolitica 4/O:3 infections in dogs and cats. METHODS AND RESULTS: Transmission of Y. enterocolitica 4/O:3 to pets via contaminated pork was studied using PFGE with NotI, ApaI and XhoI enzymes. A total of 132 isolates, of which 16 were from cat and dog faeces and 116 from raw pork samples, were recovered in Finland during 1998-99. Cat 1, whose diet consisted mostly of raw pig hearts and kidneys, excreted Y. enterocolitica 4/O:3 of genotype G4. This predominant genotype was also found in isolates recovered from the pig heart, liver, kidney, tongue and ear, and minced pork samples. Dog 2, which was fed raw minced pork, excreted Y. enterocolitica of genotype G13. This genotype was also identified in isolates recovered from the pig heart, kidney and tongue, and minced pork samples. CONCLUSION: These results show that raw pork can be an important source of Yersinia enterocolitica 4/O:3 infections in dogs and cats. Significance and Impact of the Study: Raw pork should not be given to pets.     

Yersinia enterocolitica and related species isolated from wildlife in New York State

Fecal specimens for Yersinia screening were obtained from a variety of wild mammals, birds, reptiles, fish, and invertebrates throughout New York State. One specimen from each of 1,426 animals was examined. A total of 148 isolates of Yersinia enterocolitica and related species were obtained from 133 (9.3%) of the animals. Y. enterocolitica was isolated from 100 (7%) of the animals tested, including 81 (10%) of 812 mammals and 19 (3.3%) of 573 birds. Y. intermedia, Y. frederiksenii, and Y. kristensenii were isolated from 39 (2.7%), 5 (0.35%), and 4 (0.28%) animals, respectively. The 81 Y. enterocolitica isolates from mammals belonged to 15 serogroups and included three pathogens: two isolates of typical serogroup 0:8, the "American strain," one from a gray fox (Urocyon cinereoargenteus) and one from a porcupine (Erethizon dorsatum); and one isolate of serogroup 0:3, bacteriophage type IXb, the "Canadian strain," from a gray fox. The most prevalent serogroups recovered from mammals were 0:6,31 (16 isolates) and 0:5,27 (6 isolates). The 19 isolates of Y. enterocolitica from birds belonged to nine serogroups and included one serogroup 0:6,31 isolate from a common grackle (Quiscalus quiscula) and two serogroup 0:5,27 isolates from great horned owls (Bubo virginianus).     

A note on Yersinia enterocolitica in a swine farm watershed

Swine faeces from three pig farms in the La Crosse River watershed near La Crosse, Wisconsin, were sampled for Yersinia enterocolitica ; 19 presumptive isolates were recovered and biochemically confirmed as Y. enterocolitica. Simultaneously, during a 2mD2 cm rainfall, the confluences of runoff water flowing from the swine holding pens and of nearby streams also were sampled; a single isolate was obtained from one holding pen runoff-stream confluence. Biochemical analysis showed that the water isolate was a biotype identical with that of a swine isolate from the adjacent farm. These results demonstrate one possible mechanism for the introduction of Y. enterocolitica into water supplies; faecal material from swine, a suspected natural reservoir of the bacterium, is transported via runoff water to streams.     

A note on Yersinia enterocolitica in a swine farm watershed

Swine faeces from three pig farms in the La Crosse River watershed near La Crosse, Wisconsin, were sampled for Yersinia enterocolitica; 19 presumptive isolates were recovered and biochemically confirmed as Y. enterocolitica. Simultaneously, during a 2.2 cm rainfall, the confluences of runoff water flowing from the swine holding pens and of nearby streams were also sampled; a single isolate was obtained from one holding pen runoff-stream confluence. Biochemical analysis showed that the water isolate was a biotype identical with that of a swine isolate from the adjacent farm. These results demonstrate one possible mechanism for the introduction of Y. enterocolitica into water supplies; faecal material from swine, a suspected natural reservoir of the bacterium, is transported via runoff water to streams.     

Note: Isolation, characterization and epidemiology of Yersinia enterocolitica from humans and animals

During an 11-year period (1983 to 1994), 51 strains of Yersinia enterocolitica were isolated from humans and animals. Specimens were collected from a total of 3601 sources consisting of 956 patients with enteritis, 300 patients with urinary tract infection, 1564 healthy humans, 510 swine, 38 guinea-pigs, 118 rats and 115 rabbits. Five strains of Y. enterocolitica , bio/serogroups 2/O:9 and 4/O:3, virulence positive, were recovered from patients. Forty-two variants of Y. enterocolitica belonging to pathogenic serogroup O:3, Voges-Proskauer-negative biogroup 3 were recovered from swine, rats and rabbits. The rate of isolation of Y. enterocolitica from diarrhoeal swine was apparently greater than those from healthy swine. The incidence of human infections due to Y. enterocolitica was very low and bioserogroups of isolates were different from the strains which were isolated from animals. There was no evidence to suggest that swine were the source of Y. enterocolitica in humans.     

Isolation of virulent Yersinia enterocolitica from porcine tongues.

Thirty-one tongues from apparently normal, freshly slaughtered pigs were assayed for the presence of Yersinia enterocolitica by different enrichment and postenrichment techniques. Sixteen different isolates were recovered, including six of serotype O:8, four of serotype O:6,30, two of serotype O:3 phage type IXb, and one each of serotypes O:13,7, O:18, and O:46. One isolate was not typable. Cold enrichment in phosphate-buffered saline followed by treatment with dilute KOH or subsequent enrichment in modified Rappaport broth recovered 12 and 7 isolates, respectively. Four of the same isolates were recovered from the same tongues by both procedures. Cold enrichment without a selective postenrichment treatment recovered two isolates. Direct enrichment in modified Rappaport broth or modified selenite broth was ineffective in recovering yersiniae, as no isolates were obtained by either method. All of the serotype O:8 isolates were virulent to mice, causing the death of adults after oral challenge. This is the first report that associates Y. enterocolitica serotype O:8 with a natural reservoir.     

Comparison of the biotypes of Yersinia enterocolitica isolated from pigs, cattle and sheep at slaughter and from humans with yersiniosis in Great Britain during 1999-2000

AIMS: To investigate the relationship between livestock carriage of Yersinia enterocolitica and human disease. The biotypes/serotypes of strains recovered from the faeces of pigs, cattle and sheep at slaughter during a national survey in Great Britain in 1999-2000, were compared with those of strains isolated from human cases of yersiniosis during the same period. METHODS AND RESULTS: The faecal carriage of Y. enterocolitica by cattle, sheep and pigs at slaughter was 6.3, 10.7 and 26.1%, respectively. Yersinia enterocolitica biotype (BT) 1a was the most frequently isolated biotype from livestock (58%) and was the predominant biotype (53%) isolated from human cases over the same period. The main recognized pathogenic Y. enterocolitica biotype isolated from livestock was BT3 (O:5,27) (35% of sheep, 22% of pigs and 4% of cattle) but this biotype was not detected in any of the human isolates investigated. The major pathogenic biotypes of strains isolated from humans were BT3 (O:9) (24%) and BT4 (O:3) (19%) whereas of the veterinary isolates investigated, only pigs (11%) carried BT3 (O:9) strains. CONCLUSIONS: Because of significant overlaps in phenotypes of the veterinary and human strains it is not possible to comment on the correlation between host and pathogenicity, especially of biotype 1a. SIGNIFICANCE AND IMPACT OF THE STUDY: The data suggest that further investigations using methods with greater discriminatory power are required. However the data also suggests that pigs may be the primary reservoir for human pathogenic Y. enterocolitica infection.     

Evaluation of usefulness for selected virulence markers for identifying pathogenic Yersinia enterocolitica strains. IV. Genes myfA and ureC

We check by polymerase chain reaction (PCR) the presence of gene ureC and myfA, encoding subunits of urease and Myf fimbriae, among clinical and food-originated strains of Yersinia to determine their usefulness as molecular virulence markers of Y. enterocolitica. The examinations were done on 130 clinical strains of Y. enterocolitica O:3/4 isolated in Poland from humans. All strains were obtained from stool and possessed the virulence plasmid pYV. In addition 40 isogenic, plasmid-cured strains were tested. The 52 strains including Y. enterocolitica (biotype 1A, 4, 2 and 1B), Y. pseudotuberculosis, Y. intermedia, Y. frederiksenii, Y. kristensenii, E. coli, Citrobatcer, Shigella and Salmonella were used as controls. The PCR assay resulted in detection of genes: ureC and myfA in genomic DNA of all 130 tested clinical strains of Y. enterocolitica pYV+, as well as in plasmid cured strains. Furthermore, ureC was found in all tested strains of Y. enterocolitica biotype A1 and in one strain of Y. intermedia and Y. kristensenii. In contrast to ureC, myfA was detected only in strains of Y. enterocolitica considered as pathogenic. Obtained results show, gene myfA seems to be the reliable virulence marker of Y. enterocolitica, whereas ureC is not recommended for identification of pathogenic strains of this species.     

Application of Yersinia kristensenii bacteriocin as a specific marker for the rapid identification of suspected isolates of Yersinia enterocolitica

Out of 143 suspected foods and clinical isolates of the genus Yersinia , 77 isolates were bacteriocin-sensitive and 66 bacteriocin non-sensitive. Of the 77 bacteriocin-sensitive isolates, 72 (93.5%) were identified as Y. enterocolitica and 5 (6.49%) as Y. frederiksenii. Out of 66 bacteriocin non-sensitive suspected isolates, 22 (33.3%) were identified as Yersinia spp. other than Y. enterocolitica and 43 (65.1%) were other Gram-negative bacteria with the exception of one (1.5%) isolate identified as Y. enterocolitica.     

Physical maps of bovine papillomavirus type 1 and type 2 genomes.

Physical maps of bovine papillomavirus type 1 and type 2 (BPV-1 and BPV-2) DNA were constructed from analysis of the electrophoretic mobilities of restriction endonuclease cleavage fragments from dual digests. BPV-1 DNA was sensitive to Hind III, HindIII, EcoRI, HpaI, AND BamHI, with all but HindII yielding single scissions. BPV-2 DNA was resistant to EcoRI, and HindIII had one cleavage site whereas HpaI, BamHI, and HindII yielded multiple fragments. Of four BPV-1 isolates examined, DNA from one isolate was resistant to HindIII, and another DNA isolate was resistant to BamHI. The three BPV-2 isolates examined were uniformly sensitive to the restriction endonucleases employed.     

Evaluation of Virulence Test Procedures for Yersinia enterocolitica Recovered from Foods

Recently a heat stable toxin (ST) and the vw factors of the plague bacteria were identified in Yersinia enterocolitica recovered from human infections. The vw factors were reported to be associated with a plasmid of 42-46 M Daltons in size and were essential for the expression of virulence. With this knowledge virulence tests were developed which allowed us to assess the virulence potential of food-borne Y. enterocolitica regardless of biotypes or serotypes. The tests evaluated were: (1) rapid presumptive test for the virulence plasmid; (2) gel electrophoretic confirmation of the virulence plasmid; (3) Laird's qualitative oral feeding test with thirst stressed mice; (4) quantitative LD₅₀ determination by i.p. injection of the mouse lethal ( i.e. serotype 0:8) strains in saline; (5) quantitative LD₅₀ determination of mouse non-lethal ( i.e. serotype 0:3) strains by i.p. injection of these strains suspended in 1 ml of 10% iron dextran saline solution for virulence enhancement. These tests were evaluated with the serotypes 0:3 and 0:8 strains associated with human infections with and without the virulence plasmid with reproducible results. Then the virulence tests procedures were applied to 79 food isolates. The virulence plasmid was detected only in the Nilehn biotype 2, 3 and 4 strains, but it was absent in Nilehn biotype 1 or the atypical strains that ferment rhamnose. The virulence of food and clinical isolates of Y. enterocolitica can be assayed fairly accurately with the above tests.     

The incidence of Yersinia enterocolitica and Yersinia enterocolitica-like organisms in raw and pasteurized milk in Northern Ireland

Yersinia enterocolitica and Y. enterocolitica-like bacteria were frequently isolated from samples of both raw bulked milk (34/150) and farm bottled (raw) milk (5/20). These bacteria were also found to contaminate creamery pasteurized milk (6/100 samples) and farm pasteurized milk (4/50 samples). Although Y. enterocolitica was the most commonly isolated species, Y. intermedia and Y. frederiksenii were also frequently obtained (52, 31 and 15% of isolates, respectively). Also, one atypical strain was identified as Y. aldovae. The Y. enterocolitica strains were largely biotype 1 (20/27) including five strains which could ferment lactose. One third of the Y. enterocolitica strains were not typable, but of those which were, the serotypes were 0:34 (18.5%), 0:5.27 (18.5%), 0:6.3 (15%), 0:4 (11%) and 0:7 (4%). Pre-enrichment in trypticase-soy broth (TSB) (at 22 degrees C for 24 h) followed by selective enrichment in bile-oxalate-sorbose broth (at 22 degrees C for 6 d) allowed the recovery of 92.3% of all isolates, as compared with 15.4% using cold enrichment in TSB at 4 degrees C for 21 d.     

Identification of Xanthomonas campestris pv. Juglandis from (Persian) English Walnut Nursery Trees in South Africa

Bacterial isolates producing yellowish colonies on Nutrient Agar were recovered from symptoms of suspect walnut blight disease on leaves of nursery trees in the southwestern Cape Province of South Africa. The isolates were identified by pathogenicity tests on leaves of walnut and plum trees in the greenhouse. Fifteen isolates from four cultivars at two nurseries produced typical lesions of blight on walnut and one isolate. typical lesions of bacterial spot disease on plum leaves. Cluster analysis was done on 28 characteristics recorded from colony growth. colour. form. and elevation on four different culture media, and starch hydrolysis on a semi-selective medium for the isolation of Xanthomonas campestris pv. juglandis. Total DNA of the isolates was digested with restriction endonuclease Spel and resolved by contour-clamped homogeneous electric field (CHEF) electrophoresis. Two phenotypic clusters were distinguished among the 15 South African and one reference strain of X.c.pv. juglandis at the 54%S_sm level. The isolate which induced disease symptoms on plum grouped with reference strains of Xanthomonas campestris pv. pruni in a third cluster. Two-thirds of the isolates were not characterized on the semi-selective medium for X.c. pv. juglandis. DNA restriction fragment banding patterns were similar for most isolates of X.c.juglandis in the same phenotypic cluster. However, DNA banding patterns were non-distinct for some isolates with similar phenotypic characters. Phenotypic characteristics and DNA restriction fragment banding patterns of the isolates were not correlated with geographical origin or cultivar specificity.     

The incidence of Yersinia enterocolitica and Yersinia enterocolitica-like organisms in raw and pasteurized milk in Northern Ireland

Yersinia enterocolitica and Y. enterocolitica -like bacteria were frequently isolated from samples of both raw bulked milk (34/150) and farm bottled (raw) milk (5/20). These bacteria were also found to contaminate creamery pasteurized milk (6/100 samples) and farm pasteurized milk (4/50 samples). Although Y. enterocolitica was the most commonly isolated species, Y. intermedia and Y. frederiksenii were also frequently obtained (52, 31 and 15% of isolates, respectively). Also, one atypical strain was identified as Y. aldovae . The Y. enterocolitica strains were largely biotype 1 (20/27) including five strains which could ferment lactose. One third of the Y. enterocolitica strains were not typable, but of those which were, the serotypes were 0:34 (18.5%), 0:5,27 (18.5%), 0:6,30 (15%), 0:4 (11%) and 0:7 (4%). Pre-enrichment in trypticase-soy broth (TSB) (at 22°C for 24 h) followed by selective enrichment in bile-oxalate-sorbose broth (at 22°C for 6 d) allowed the recovery of 92.3% of all isolates, as compared with 15.4% using cold enrichment in TSB at 4°C for 21 d.     

Identification and characterization of pathogenic Yersinia enterocolitica isolates by PCR and pulsed-field gel electrophoresis

Approximately 550 to 600 yersiniosis patients are reported annually in Sweden. Although pigs are thought to be the main reservoir of food-borne pathogenic Yersinia enterocolitica, the role of pork meat as a vehicle for transmission to humans is still unclear. Pork meat collected from refrigerators and local shops frequented by yersiniosis patients (n=48) were examined for the presence of pathogenic Yersinia spp. A combined culture and PCR method was used for detection, and a multiplex PCR was developed and evaluated as a tool for efficient identification of pathogenic food and patient isolates. The results obtained with the multiplex PCR were compared to phenotypic test results and confirmed by pulsed-field gel electrophoresis (PFGE). In all, 118 pork products (91 raw and 27 ready-to-eat) were collected. Pathogenic Yersinia spp. were detected by PCR in 10% (9 of 91) of the raw pork samples (loin of pork, fillet of pork, pork chop, ham, and minced meat) but in none of the ready-to-eat products. Isolates of Y. enterocolitica bioserotype 4/O:3 were recovered from six of the PCR-positive raw pork samples; all harbored the virulence plasmid. All isolates were recovered from food collected in shops and, thus, none were from the patients' home. When subjected to PFGE, the six isolates displayed four different NotI profiles. The same four NotI profiles were also present among isolates recovered from the yersiniosis patients. The application of a multiplex PCR was shown to be an efficient tool for identification of pathogenic Y. enterocolitica isolates in naturally contaminated raw pork.     

Different Yersinia enterocolitica 4:O3 genotypes found in pig tonsils in Southern Germany and Finland

The distribution of different genotypes of Y. enterocolitica 4:O3 strains recovered from pig tonsils in Southern Germany and Finland in 1999-2000 was investigated. A total of 96 and 207 Y. enterococolitica 4:O3 isolates recovered from 47 and 66 tonsils of finishing pigs in Germany and Finland, respectively, were characterised with PFGE using NotI enzyme. In all, 39 different NotI profiles were obtained, only one of which, NB1, was found in both Germany and Finland. All strains were further characterised with ApaI and XhoI enzymes. When the 54 German and 74 Finnish strains were characterised with all three enzymes, 51 genotypes were obtained. The 23 genotypes found in German strains differed from the 28 found in Finnish strains. These results indicate that Y. enterocolitica 4:O3 genotypes have a differential geographical distribution and thus can be used in epidemiological studies.     

The application of PCR fingerprinting to the differentiation of Yersinia enterocolitica strains isolated from humans and pigs

The distribution of different genotypes of Yersinia enterocolitica strains recovered from humans and from healthy pigs was investigated using PCR fingerprinting. The thirty six strains of Y. enterocolitica from humans, thirty five strains from pigs and Y. enterocolitica ATCC 9610 strain were included in this study. The tested strains of Y. enterocolitica belonged to O3 and O9 serogroups. The PCR fingerprinting using EAE5 primer (5' CTT AAT CTC AGT AAT GCT GGC CTT GG) made it possible to form five groups among the tested Y. enterocolitica strains. Two groups were very numerously represented by the tested strains. The thirty of Y. enterocolitica O3 strains from humans (thirty one of tested) and eighteen of Y. enterocolitica O3 strains from pigs (twenty of tested) belonged to one group. This group also included Y. enterocolitica ATCC9610 strain and four Y. enterocolitica O9 strains from pigs. All investigated Y. enterocolitica O9 strains from humans and the majority of Y. enterocolitica O9 strains isolated from pigs created a second, numerous group. The third genotype was created by two strains O9 from pigs, and the remaining two strains, isolated from pigs, belonging to O3 and O9 serogroups showed different binding patterns revealed by gel electrophoresis and created two other genotypes. The tested Y. enterocolitica strains which were isolated from humans formed only two groups but Y. enterocolitica strains isolated from pigs were found in five groups but such as the Y. enterocolitica strains from humans, the majority of strains from pigs were in first and second group. The Y. enterocolitica O3 strains regardless of their origin mostly represented the same PCR fingerprinting profile. The tested Y. enterocolitica O9 strains were more genetically diverse and represented four PCR fingerprinting profiles.     

Patterns of infection by Salmonella and Yersinia spp. in commensal house mouse (Mus musculus domesticus) populations

AIMS: This study sought to examine the risk posed by house mice transmitting pathogens to livestock on typical mixed-agriculture farms in the UK. METHODS AND RESULTS: In a 10-month longitudinal study at one farm, 222 faecal samples were taken from mice and 57 swabs from the farm environment; 3.2% and 15.8%, respectively, were positive for Yersinia. Seventy-five intestinal samples were taken from house mice from three other farms and 9.3% were positive for Yersinia. The commonest species was Y. enterocolitica (of a wide range of serotypes); all isolates were non-pathogenic, except one of Y. pseudotuberculosis. Salmonella was not isolated from any sample. CONCLUSION: This study provides additional evidence that house mice are generally not significant vectors of either pathogenic Yersinia strains or Salmonella species. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first longitudinal study of Yersinia in any small mammal population, and shows infection to be a dynamic series of generally non-pathogenic, transient infections.