Enterocolitica Bioserotype Research Articles

Wide variety of bioserotypes of enteropathogenic Yersinia in tonsils of English pigs at slaughter

The tonsils of 630 pigs from 45 English farms using three different rearing methods (Assured British Pigs, Open Management and Organic) were examined between 2003 and 2005 in order to investigate if the low incidence of human yersiniosis could be attributed to a low prevalence of enteropathogenic Yersinia among English pigs. In addition, different isolation methods were compared, possible differences in prevalence among pigs were studied, as well as the prevalence of different bioserotypes of enteropathogenic Yersinia. A high prevalence and a wide diversity of bioserotypes of enteropathogenic Yersinia compared to other European countries were observed. The prevalence of pathogenic Yersinia enterocolitica was 44% and of Yersinia pseudotuberculosis 18%. Overall, 60% of pigs carried enteropathogenic Yersinia. Y. pseudotuberculosis was detected on 78% of farms and Y. enterocolitica on 69%. The most common bioserotypes of Y. enterocolitica were 2/O:9 (33%) and 2/O:5 (26%), and of Y. pseudotuberculosis 2/O:3 (34%), 1/O:1 (26%) and 1/O:4 (24%). Cold enrichment gave the highest isolation rate for both species. Y. enterocolitica was more prevalent ( P < 0.001) and Y. pseudotuberculosis less prevalent ( P < 0.05) in winter than in summer in Eastern England. Y. enterocolitica was more common in Eastern England and in assured British pigs, whereas Y. pseudotuberculosis was more common in Western England and in organic pigs. Y. pseudotuberculosis 1/O:1 was predominant ( P < 0.05) in Western England. Types 1/O:4 ( P < 0.05) and 2/O:3 ( P < 0.001) predominated in Eastern England. The high prevalence of Y. enterocolitica bioserotypes 2/O:9 and 2/O:5 found in this study suggests that English pigs are an important reservoir of these bioserotypes whereas in other European countries bioserotype 4/O:3 predominates.

Prevalence of EnteropathogenicYersiniain Estonian, Latvian, and Russian (Leningrad Region) Pigs

Tonsils of 457 fattening pigs from Estonia (n = 151), Latvia (n = 109), and the Leningrad Region of Russia (n = 197) were collected between 2004 and 2007 to study the prevalence of enteropathogenic Yersinia in slaughter pigs. Yersinia enterocolitica and Yersinia pseudotuberculosis were isolated by selective and cold enrichment. Pathogenic Y. enterocolitica and Y. pseudotuberculosis were identified by PCR targeting the chromosomal genes ail and inv, respectively. The presence of the virulence plasmid was confirmed by PCR targeting the virF gene of Y. enterocolitica and Y. pseudotuberculosis. The prevalence of ail-positive Y. enterocolitica was 89% in Estonia, 64% in Latvia, and 34% in Russia, with 81% of ail-positive samples being virF-positive. A statistically significant (p < 0.05) difference between Estonian and Latvian pigs and between pigs from Latvia and the Leningrad Region of Russia was observed when assuming randomized sampling. Y. enterocolitica bioserotype 4/O:3 was the only pathogenic type found. The prevalence of inv and virF-positive Y. pseudotuberculosis was higher in Russia (7%) than in Latvia (5%) and Estonia (1%), with a statistically significant difference between pigs from Estonia and the Leningrad Region of Russia when assuming both randomized sampling and clustering at farms. All Y. pseudotuberculosis isolates were bioserotype 2/O:3. A total of eight pigs (2%), one pig from Latvia and seven pigs from the Leningrad Region of Russia, carried both pathogenic Y. enterocolitica and Y. pseudotuberculosis in the tonsils. Cold enrichment was found to be a more efficient method compared to selective enrichment to isolate both species. Pigs seem to be an important reservoir of human enteropathogenic Y. enterocolitica 4/O:3 and Y. pseudotuberculosis 2/O:3 in these countries.

A novel insertion sequence element, IS Yen2, as an epidemiological marker for weakly pathogenic bioserotypes of Yersinia enterocolitica

The structure and distribution of IS Yen2, a new Yersinia enterocolitica insertion sequence element, were investigated. IS Yen2 is related to IS elements of the IS 21 family and is present in two isoforms in Y. enterocolitica serotype O:3. Analysis of all copies of both isoforms, IS Yen2A and IS Yen2B, by PCR and sequencing indicated that they are not flanked by direct repeats which are typical of the IS 21 family of repetitive elements. IS Yen2 is present in multiple copies in Y. enterocolitica O:3 and O:9 and in a single copy in Y. enterocolitica O:1 and O:2 serotypes. The probe for IS Yen2 efficiently detected all weakly pathogenic Y. enterocolitica bioserotypes investigated, whereas it did not hybridize with other strains. This indicates that IS Yen2 can serve as an additional tool for Y. enterocolitica differentiation and epidemiological studies. Distribution of the different groups of IS elements in two Y. enterocolitica pathotypes is in favor of the parallel evolution of American and European Y. enterocolitica strains.

High Prevalence of yadA-Positive Yersinia enterocolitica in Pig Tongues and Minced Meat at the Retail Level in Finland

Polymerase chain reaction (PCR) was used to determine the prevalence of yadA-positive Yersinia enterocolitica in pig tongues and minced meat at the retail level in Finland and to confirm the yadA-positive Y. enterocolitica isolates recovered from the same samples using the conventional culture method. A total of 51 pig tongues purchased at 12 retail outlets and 255 minced meat samples purchased at 40 retail outlets in the Helsinki area were studied. The prevalence of Y. enterocolitica carrying the yadA gene was 92% in pig tongues and 25% in minced meat using PCR and 78% in tongues and 2% in minced meat with the culture method. The prevalence of yadA-positive tongues was higher (98%) when both PCR- and culture-positive results were included because Y. enterocolitica carrying the yadA gene could also be isolated in three PCR-negative tongue samples. In the minced meat samples, all PCR-negative samples were also culture-negative. With the culture method, 66 of 80 yadA-positive isolates in 38 tongues and all yadA-positive isolates (4) in four minced meat samples were recovered after selective enrichment. A total of 92 isolates of Y. enterocolitica bioserotype 4/O:3 in tongues and 5 isolates in minced meat were found, of which 13% in tongues and 20% in minced meat did not carry the yadA gene.

Pharmacists Play Large Role in 1975 NPPW

Enteropathogenic Yersinia enterocolitica bioserotype 4/O:3 are the most frequent cause of human yersiniosis worldwide with symptoms ranging from mild diarrhea to severe complications of mesenteric lymphadenitis, liver abscesses and postinfectious extraintestinal sequelae. The main reservoir host of 4/O:3 strains are pigs, which represent a substantial disease-causing potential for humans, as they are usually asymptomatic carriers. Y. enterocolitica O:3 initiates infections by tight attachment to the intestinal mucosa. Colonization of the digestive tract is frequently followed by invasion of the intestinal layer primarily at the follicle-associated epithelium, allowing the bacteria to propagate in the lamina propria and disseminate into deeper tissues. Molecular characterization of Y. enterocolitica O:3 isolates led to the identification of (i) alternative virulence and fitness factors and (ii) small genetic variations which cause profound changes in their virulence gene expression pattern (e.g. constitutive expression of the primary invasion factor InvA). These changes provoke a major difference in the virulence properties, i.e. reduced colonization of intestinal tissues in mice, but improved long-term colonization in the pig intestine. Y. enterocolitica O:3 strains cause also a considerably lower level of proinflammatory cytokine IL-8 and higher levels of the anti-inflammatory cytokine IL-10 in porcine primary macrophages, as compared to murine macrophages, which could contribute to limiting inflammation, immunopathology and severity of the infection in pigs.