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1.
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.  相似文献   

2.
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.  相似文献   

3.
Many selective enrichment methods for the isolation of Yersinia enterocolitica from foods have been described. However, no single isolation procedure has been described for the recovery and identification of various plasmid-bearing serotypes. A single improved procedure for selective enrichment, isolation, identification, and maintenance of plasmid-bearing virulent serotypes of Y. enterocolitica from pork samples was developed. Enrichment at 12 degrees C in Trypticase soy broth containing yeast extract, bile salts, and Irgasan was found to be an efficient medium for the recovery of plasmid-bearing virulent strains of Y. enterocolitica representing O:3; O:8; O:TACOMA; O:5, O:27; and O:13 serotypes. MacConkey agar proved to be a reliable medium for the isolation of presumptive colonies, which were subsequently confirmed as plasmid-bearing virulent strains by Congo red binding and low calcium response. Further confirmation by multiplex PCR employed primers directed at the chromosomal ail and plasmid-borne virF genes, which are present only in pathogenic strains. The method was applied to pig slaughterhouse samples and was effective in isolating plasmid-bearing virulent strains of Y. enterocolitica from naturally contaminated porcine tongues. Strains isolated from ground pork and tongue expressed plasmid-associated phenotypes and mouse pathogenicity.  相似文献   

4.
Growth of Yersinia enterocolitica strains representing serogroups O: 3, O: 5, 27, O:6, 30, O:8, O:9 (human isolates) and O:6, 31 (food isolate) were inhibited in the presence of a bacteriocin produced by Yersinia kristensenii at high initial cell count of 106 ml-1. Complete (100%) inactivation of most Y. enterocolitica cells of different serotypes was observed within 24 h at low initial cell counts of 104 ml-1. Complete injury of the cells was observed within 4–8 h, with all the serotypes at 10°C and 28°C. The degree of susceptibility to the injury and the recovery of cells from the injury varied from serogroup to serogroup.  相似文献   

5.
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.  相似文献   

6.
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.  相似文献   

7.
Wang X  Gu W  Cui Z  Luo L  Cheng P  Xiao Y  Tang L  Kan B  Jing H 《PloS one》2012,7(5):e37309
The predominant bioserotypes of pathogenic Yersinia enterocolitica in China are 2/O: 9 and 3/O: 3; no pathogenic O: 8 strains have been found to date. Multiple-Locus Variable-Number Tandem-Repeat Analysis (MLVA) based on seven loci was able to distinguish 104 genotypes among 218 pathogenic Y. enterocolitica isolates in China and from abroad, showing a high resolution. The major pathogenic serogroups in China, O: 3 and O: 9, were divided into two clusters based on MLVA genotyping. The different distribution of Y. enterocolitica MLVA genotypes maybe due to the recent dissemination of specific clones of 2/O: 9 and 3/O: 3 strains in China. MLVA was a helpful tool for bacterial pathogen surveillance and investigation of pathogenic Y. enterocolitica outbreaks.  相似文献   

8.
Yersinia enterocolitica is one of the few human pathogens that grows at the proper food refrigeration temperatures of 0 to 5 degrees C. Although the isolation of environmental biotypes of Y. enterocolitica from many types of food and water has been reported in the literature, the recovery of the sensitive strains inoculated into foods has been slow and uncertain. Rapid recovery of several clinical strains inoculated into meats was accomplished by using two modified selenite broths without added nutrients. It was critical to restrict the sample size of the blended meat suspension at the 0.2-g/100 ml level, thereby restricting the growth of the total bacterial population in the selenite enrichment media. Otherwise, the slower growing Y. enterocolitica would be overwhelmed by the faster growing normal bacterial flora from the meat. Both the resistant serotype O:3 and the sensitive O:8 clinical isolates of Y. enterocolitica were recovered from the modified selenite enrichment media after 2 and 3 days of incubation at 22 degrees C.  相似文献   

9.
The distribution of Yersinia enterocolitica in slaughtered pigs in China was studied. A total of 8,773 samples were collected and examined from different pig abattoirs in 11 provinces from 2009 to 2011. Of these, 4,495 were oral-pharyngeal swab (tonsils) samples from pigs, 1,239 were from intestinal contents, and 3,039 were feces samples from abattoirs or local pigpens. The data showed that 1,132 strains were obtained, from which the isolation rate for Yersinia enterocolitica was 19.53% (878/4,495) from the tonsil samples, 7.51% (93/1,239) from intestinal contents, and 5.30% (161/3,039) from feces. Of the 850 pathogenic Yersinia strains, except for three of bioserotype 2/O:9 and three of bioserotype 4/O:3, most (844/850) were of bioserotype 3/O:3. Interestingly, pathogenic Y. enterocolitica accounted for the majority of the isolated strains from most provinces (85.17% to 100%), whereas from Heilongjiang, 96.52% (111/115) were classified as nonpathogenic biotype 1A with various serotypes, and only 3.48% of the strains (4/115) were pathogenic 3/O:3. All of the pathogenic strains were analyzed using pulsed-field gel electrophoresis (PFGE), and 49 patterns were obtained for the O:3 pathogenic strains; most of them were K6GN11C30021 (53.13%: 450/847) and K6GN11C30012 (21.37%: 181/847). Several strains from diarrhea patient samples revealed PFGE patterns identical to that from samples of local pigs, suggesting a possible link between porcine isolates and human infection. The results above suggested that Yersinia enterocolitica in slaughtered pigs from Chinese abattoirs was characterized by region-specific PFGE patterns and confirmed that strains isolated from pigs are closely related to those from human infections.  相似文献   

10.
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.  相似文献   

11.
In this study, we aimed to investigate the distribution of virulence genes in clinical isolates of pathogenic Yersinia enterocolitica. Two thousand six hundred stool samples were collected from 2600 patients with diarrhea, and were tested using the culture method and real-time PCR. Then, all isolates of pathogenic Y. enterocolitica cultured from the culture method were examined for virulence genes (inv, ail, ystA, ystB, ystC, yadA, virF) by PCR and for the presence of plasmid by four phenotypic tests. As a result, 160 pathogenic strains were successfully detected by the culture method, including bio/serotype 1A/unknown (4), 1B/unknown (8), 2/O:9 (39), 2/unknown (7), 3/O:3 (22), 3/unknown (6), 4/O:3 (55), 4/unknown (10) and 5/unknown (9). The positive rate of virulence genes tested in 160 isolates was inv (100%), ail (94%), ystA (93%), ystB (7.5%), ystC (5%), yadA (89%) and virF (82%) while the phenotypic test included autoagglutination (87%), binding of crystal violet (89%), calcium-dependent growth (74%) and Congo red absorption (78%), respectively. Finally, we found that not all pathogenic Y. enterocolitica necessarily carry all traditional virulence genes in both chromosomes and plasmids to cause illness. Perhaps, some of them, lacking some traditional virulence genes, contain other unknown virulence markers that interact with each other and play an important role in the diverse pathogenesis of pathogenic Y. enterocolitica.  相似文献   

12.
Yersinia enterocolitica, an important cause of human gastroenteritis generally caused by the consumption of livestock, has traditionally been categorized into three groups with respect to pathogenicity, i.e., nonpathogenic (biotype 1A), low pathogenicity (biotypes 2 to 5), and highly pathogenic (biotype 1B). However, genetic differences that explain variation in pathogenesis and whether different biotypes are associated with specific nonhuman hosts are largely unknown. In this study, we applied comparative phylogenomics (whole-genome comparisons of microbes with DNA microarrays combined with Bayesian phylogenies) to investigate a diverse collection of 94 strains of Y. enterocolitica consisting of 35 human, 35 pig, 15 sheep, and 9 cattle isolates from nonpathogenic, low-pathogenicity, and highly pathogenic biotypes. Analysis confirmed three distinct statistically supported clusters composed of a nonpathogenic clade, a low-pathogenicity clade, and a highly pathogenic clade. Genetic differences revealed 125 predicted coding sequences (CDSs) present in all highly pathogenic strains but absent from the other clades. These included several previously uncharacterized CDSs that may encode novel virulence determinants including a hemolysin, a metalloprotease, and a type III secretion effector protein. Additionally, 27 CDSs were identified which were present in all 47 low-pathogenicity strains and Y. enterocolitica 8081 but absent from all nonpathogenic 1A isolates. Analysis of the core gene set for Y. enterocolitica revealed that 20.8% of the genes were shared by all of the strains, confirming this species as highly heterogeneous, adding to the case for the existence of three subspecies of Y. enterocolitica. Further analysis revealed that Y. enterocolitica does not cluster according to source (host).  相似文献   

13.
Among Yersinia enterocolitica strains of 32 serovars, proposed as typing strains, some strains were found to belong to new species. Y. enterocolitica sensu stricto was represented by 21 serovars in the collection of typing strains. The occurrence of different Yersinia serovars in patients with acute enteric diseases of unknown etiology in Leningrad in 1983-1986 was determined with the use of the set of monoreceptor to 21 serovars. Out of 2,947 cultures studied by biochemical and serological methods, 81% were typed. Among them 18 Y. enterocolitica serovars were determined. Their characteristic feature was the prevalence of serovar O3 and an insignificant proportion of serovar O9. More frequently Yersinia were detected in patients with the primary diagnosis of acute enteric diseases (93.5%). The overwhelming majority (two-thirds) of Yersinia strains were isolated from children. A great number of strains detected in this study (70%) was isolated on days 10-15 of the bacteriological examination. In 927 cultures the following biovars were determined: the strains of serovar O3 belonged to biovar 4 and all other strains, to biovar 1.  相似文献   

14.
Universal Preenrichment (UP) medium was used successfully for the simultaneous recovery of two strains each of Escherichia coli O157:H7 and Yersinia enterocolitica in the presence of Listeria monocytogenes and Salmonella typhimurium. E. coli O157:H7 and Y. enterocolitica populations reached ca. 108 CFU/ml in UP medium in 18 h from an initial level ofca. 102 CFU/ml. Addition of OxyraseTM enhanced the growth of both E. coli O157:H7 strains and one strain of Y. enterocolitica. These three strains were able to recover from heat injury by 6 h when 24-h cultures were tested, but not when 18-h cultures were used. Injured and noninjured E. coli O157:H7 could be recovered from artificially inoculated food samples (shredded cheddar cheese, turkey ham, hot dogs, mayonnaise, and ground beef) in UP medium supplemented with OxyraseTM (UPO) by 18 h using immunoblotting. Y. enterocolitica could be recovered from turkey ham, hog dogs, and mayonnaise by direct plating on CIN agar from UPO medium. However, recovery of Y. enterocolitica from shredded cheddar cheese and ground beef required subsequent selective enrichment in sorbitol bile broth and isolation on Cefsulodin Irgasan Novobiocin agar (CIN). UPO medium can be used for simultaneous detection of E. coli O157:H7 and Y. enterocolitica from foods. However, subsequent selective enrichment and isolation on selective plating media are required for isolation of Y. enterocolitca from raw foods containing high population levels of background microflora.  相似文献   

15.
Eighty strains of Yersinia enterocolitica and related species isolated from slaughtered pigs and pork products were tested for possession of virulence-associated phenotypes by employing 12 in vivo and in vitro assays. The isolates could be broadly divided into two groups: (i) strains belonging to pathogenic bioserotypes of Y. enterocolitica that displayed virulence-associated characteristics in most or all assays and (ii) strains belonging to Y. enterocolitica biotype 1A and to related species that were largely negative in these assays. No individual test was found as a single reliable measure of virulence. All strains belonging to Y. enterocolitica serotype O:1,2,3 were pyrazinamidase positive (indicates avirulence) and autoagglutination negative but were positive in all other virulence assays. Salt aggregation was found to be a better indicator of virulence than latex particle agglutination, both of which measure surface hydrophobicity. Overall, tissue culture cell invasion provided the best selection of a subpopulation of yersiniae that are potentially virulent. However, crystal violet and Congo red binding assays among others provided good prediction of virulence at the time of testing. Our results provide further evidence that swine may constitute an important reservoir of human pathogenic strains.  相似文献   

16.
A new enrichment medium for the recovery of pathogenic Yersinia enterocolitica serogroup O:3 from naturally infected meat products based on three selective agents, Irgasan, ticarcillin, and potassium chlorate (ITC), was compared with several other one- or two-step enrichments. Y. enterocolitica serogroup O:3 was recovered from 96.5% of 29 pork tongues, 24% of 50 ground pork samples, 16% of 25 masseter muscle samples, and 61% of tonsils. ITC was by far the most sensitive method for the recovery of Y. enterocolitica O:3, especially from ground meat and masseter muscles, while cold and two-step enrichments yielded better results for nonpathogenic strains. Plating of ITC enrichments onto SS-deoxycholate-calcium agar gave overall better results than plating onto cefsulodin-Irgasan-novobiocin agar for serogroup O:3.  相似文献   

17.
A new enrichment medium for the recovery of pathogenic Yersinia enterocolitica serogroup O:3 from naturally infected meat products based on three selective agents, Irgasan, ticarcillin, and potassium chlorate (ITC), was compared with several other one- or two-step enrichments. Y. enterocolitica serogroup O:3 was recovered from 96.5% of 29 pork tongues, 24% of 50 ground pork samples, 16% of 25 masseter muscle samples, and 61% of tonsils. ITC was by far the most sensitive method for the recovery of Y. enterocolitica O:3, especially from ground meat and masseter muscles, while cold and two-step enrichments yielded better results for nonpathogenic strains. Plating of ITC enrichments onto SS-deoxycholate-calcium agar gave overall better results than plating onto cefsulodin-Irgasan-novobiocin agar for serogroup O:3.  相似文献   

18.
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).  相似文献   

19.
AIMS: Yersinia enterocolitica causes several syndromes in humans. The most common presentation is enterocolitis in children, presenting as fever and diarrhoea. A Y. enterocolitica multiple strain infection in twin infants was investigated. METHODS AND RESULTS: One isolate was recovered from one patient and two morphologically-different isolates were recovered from the other infant. Biochemically, all isolates were identified as Y. enterocolitica group. The genomic DNA from each strain was purified and DNA fingerprinting was performed. The banding patterns observed for Y. enterocolitica isolates 2 and 3, from patients 1 and 2, respectively, were identical when comparing the presence or absence of major bands. However, Y. enterocolitica isolate 1, from patient 1, showed a distinctive banding pattern from isolates 2 and 3. CONCLUSION: The findings indicate that one infant was colonized by more than one strain of Y. enterocolitica, demonstrating that multiple strains can colonize and invade a patient. SIGNIFICANCE AND IMPACT OF THE STUDY: Recognition of multiple strain infections can be important in diagnosis, treatment and prognosis of Y. enterocolitica infections, as well as in disease epidemiology. The technique described here offers a straightforward method for strain comparison.  相似文献   

20.
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).  相似文献   

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