Epidemiología de las infecciones por Yersinia enterocolítica / Aspects of the epidemiology of Yersinia enterocolitica: a review

Los brotes recientes de enfermedades transmitidas por los alimentos asociados a Salmonella, Listeria y Yersinia han destacado la importancia del conocimiento de los riesgos microbriológicos a que se expone la población por el consumo de estos alimentos contaminados. Tales brotes afirman la necesiad de mejorar los métodos de detección, del control del medio ambiente y de la vigilancia epidemiológica... Durante la década pasada, numerosos métodos basados en la detección del ADN bacteriano, tales como la PCR o las pruebas de hibridación, han demostrado superioridad por su mayor sensibilidad que supera por lejos la de los medios de cultivos convencionales. Una PCR en tiempo real es un método rápido y específico para la detección de Y. enterocolítica en diferentes muestras, proporcionando una alternativa superior a los métodos de detección actualmente disponibles. Esto permitiría identificar eficientemente los alimentos peligrosos debido a la contaminación con Y. enterocolítica.

Recent outbreaks of foodborne disease linked to Salmonella, Listeria, and Yersinia have highlighted consumer awarenss of microbiological problems in the food supply. Such outbreaks affirm the need form improved testing, environmental monitoring, and epidemiological surveillance. In the case of Yersinia, this bacterium's role as a newly emerged foodborne pathogen is discussed... During the las decade, numerous DNA-based methods, such as PCR and colony hybridization assays, have been designed to detect pathogenic Y. enterocolítica in natural samples more rapidly and with better sensitivity than can be achieved by culture methods. A rapid and specific real-time PCR method for the detection of pathogenic Y. enterocolitica bacteria in natural samples, provides a superior alternative to the corrently available detection methods and makes it possible to identify the foods at risk for Y. enterocolitica contamination.

Panoramic view of the occurrence of Yersinia species other than Y. pestis in Brazil

Data on the occurrence of Yersinia species. other than Y. pestis in Brazil are presented. Over the past 40 years, 767 Yersinia strains have been identified and typed by the National Reference Center on Yersinia spp. other than Y. pestis, using the classical biochemical tests for species characterization. The strains were further classified into biotypes, serotypes and phagetypes when pertinent. These tests led to the identification of Yersinia cultures belonging to the species Y. enterocolitica, Y.pseudotuberculosis, Y. intermedia, Y. frederiksenii and Y. kristensenii. Six isolates could not be classified in any of the known Yersinia species and for this reason were defined as Non-typable (NT). The bio-sero-phagetypes of these strains were diverse. The following species of Yersinia were not identified among the Brazilian strains by the classical phenotypic or biochemical tests: Y. aldovae, Y. rhodei, Y. mollaretti, Y. bercovieri and Y.ruckeri. The Yersinia strains were isolated from clinical material taken from sick and/or healthy humans and animals, from various types of food and from the environment, by investigators of various Institutions localized in different cities and regions of Brazil.

Epidemiological study on yersiniosis in pediatric acute diarrhea [with 5 tables and 5 figures]

Yersiniosis is considered one of the most important bacterial foodborne infections as their incidence among humans had increased dramatically. A total of one hundred and fifty random samples were collected from children with acute diarrhea. 50 of them had blood in stools and 100 had no blood in their stools. Samples were collected from the gastroenterology unit of Assiut University Children Hospital during the period from January to December 2005. The present study was designed to estimate the incidence of Yersinia enterocolitica and Yersinia pseudotuberculosis among diarrheal children with and without blood in stools. Moreover, demographic and clinical characteristics of the Yersinia infected children were investigated. Yersinia enterocolitica and Yersinia pseudotuberculosis could be detected in 17.33% and 13.33% of the examined children, respectively. Ecological distribution of the examined children revealed that the rate of infection was higher in rural areas [52.9%] than in urban areas [11.25%]. The majority of cases in the present study were in the age group of [> 24-60months] with a rate of [87.5%], followed by those in age group of [7 -24 months] with a rate of 18.33%. It has been determined that incidence of Yersinia species was higher among females [33.33%] than males [29.52%]. Seasonal incidence of the infection by Yersinia enterocolitica and Yersinia pseudotuberculosis was studied. Public health hazard and preventive measures to control infection were discussed

Análisis de una cepa de Yersinia enterocolitica aislada de heces diarreicas humanas en Argentina / Analysis of a Yersinia enterocoliticaisolated from human diarreic feces in Argentina

Algunos serotipos de Yersinia enterocolitica ocasionan desde diarreas hasta infecciones invasivas. El objetivo del trabajo fue analizar factores de virulencia y marcadores asociados en una cepa de Y. enterocolitica aislada de heces diarreicas humanas. El aislamiento deY. enterocolitica analizado fue incluído dentro del sub-grupo 1A.La determinación de resistencia al suero humano normal e hidrofobicidad de superficie, así como la búsqueda de los genes vir F y ail, resultaron negativos. Se demostró sin embargo producción de enterotoxina a 20 °C y también a 37 °C en condiciones de osmolaridad y pH similares a las del intestino humano. La enterotoxina, presentó reactividadpor la prueba del ratón lactante, aunque no se pudo comprobarpor PCR la presencia del gen yst. Los resultados obtenidos por nosotros, coincidentes con los de otros investigadores, indican que ciertos aislamientos clínicos de Y. enterocolitica del biotipo 1A (“avirulentas”), son capaces de causar enfermedad, probablemente a través de otros mecanismos, distintos a los caracterizados en especies de Yersinia enteropatógenas.

Some serotypes of Yersinia enterocoliticamight causediarrheas and/or invasive infections. The aim of this work was to analyze virulence factors and associated markers in a strain of Y. enterocolitica isolated from human diarrheic feces. The strain analyzed was included in the biotype 1A. The virulence markers determinationas well as the search of the genes vir F and ail,were negatives. However, it was demonstratedenterotoxin production at 20 °C, andat 37 °C in osmolarity conditions and pH similar to the human intestine. The enterotoxin presented reactivity for the infant mouse test, although it could not be proven the presence of yst gene by PCR. The results obtained by us, coincident with those of other investigators,indicated that certain clinical isolates of Y. enterocolitica of the biotype 1A (“avirulent”), could be the etiological agent of the illness trhough other mechanisms of virulence, that would differ from those previously characterized in species of enteropathogenic Yersinia.

An outbreak of food poisoning in Tamil Nadu associated with Yersinia enterocolitica.

An outbreak of food poisoning in a Tamil Nadu village, affecting 25 of 48 individuals who participated in a feast, was investigated. The risk of developing illness was associated with consumption of buttermilk (relative risk 3.8). None of the food items consumed during the feast was available for analysis. Toxin-producing Y. enterocolitica (serotype 3, biotype 4) was grown from 1 of 11 stool samples from affected individuals, as well as from a water sample from the source used to dilute the buttermilk. High titres of antibody of Yersinia were detected in 2 of 12 patients but in neither of the two groups of controls. Toxin production was noted in buttermilk incubated for 6 h with Y. enterocolitica. This is the first report from India of a food poisoning outbreak associated with this organism.

Perfil clínico y microbiológico de las infecciones entéricas por Yersinia entero colitica en niños de Santiago, Chile / Clinical and microbiological aspects of Yersinia enterocolitica enteric infections in children from Santiago, Chile

Yersinia enterocolitica es causa frecuente de infecciones intestinales endémicas en países de Europa y Norteamérica, pero la información sobre ella en Iberoamérica es escasa. El propósito de este estudio fue describir la incidencia y características clínicas de infecciones intestinales por Y. enterocolitica en 3 cohortes de niños menores de 4 años de familias de bajos recursos de Santiago. Los niños fueron vigilados activamente con visitas domiciliarias dos veces por semana, se les tomaron muestras de deposiciones en cada episodio de diarrea, como también a controles pareados por edad y sexo. Entre febrero 1987 y enero 1990 se estudiaron 1.795 episodios de diarrea. La incidencia de Y. enterocolitica en los casos de diarrea fue de 1,4% versus 0,3% en 1.780 controles (p<0,005). La diarrea asociada a Y. enterocolitica se caracterizó por deposiciones líquidas o mucosas; en ningún caso hubo síndrome disentérico, pero 11,5% evolucionaron como diarrea persistente (> 14 días); en 26,9% de los pacientes se observó fiebre (* 38-C) y ninguno requirió hospitalización. De las cepas de Yersinia aisladas, 73% correspondieron a serotipo 0:3, biotipo 4, y las restantes a los serotipos 0:7,8, 0:10 y 0:6. No se apreciaron claras diferencias estacionales, pero 50% de los aislamientos se concentraron en los meses fríos de junio, julio, agosto, septiembre. Si bien la incidencia de Y. enterocolitica en diarrea aguda infantil es baja, es importante buscarla en forma sistemática y con medios selectivos en niños menores de 2 años, considerando que puede provocar enfermedad de curso prolongado

Yersinia enterocolítica: investigación en 1 300 niños menores de 5 años con enfermedad diarreica aguda / Yersinia enterocolitica: research in 1 300 children younger than five years with acute diarrheic disease

Se investigó la presencia de Yersinia enterocolítica en las heces de 1 300 niños menores de 5 años hospitalizados por presentar enfermedad diarreica aguda en Cuba durante los años 1985-1988 en diferentes hospitales pediátricos provinciales, así como de Ciudad de La Habana. Se empleó la base de agar selectivo para Yersinia suplementada con cefsuloidin, irgasán y novobiocina (CIN) y solución salina amortiguada como medio de enriquecimiento. Este último a 4 -C durante 21 días con resiembras semanales al medio selectivo. No se obtuvo aislamiento de Yersinia enterocolítica en ninguno de los pacientes estudiados