Sorologia e suscetibilidade antimicrobiana em isolados de Escherichia coli de pesque-pagues / Serology and patterns of antimicrobial susceptibility in Escherichia coli isolates from pay-to-fish ponds

Pesquisou-se a ocorrência de Escherichia coli (EPEC, EIEC, O157) em água e peixe (pele, trato digestivo e músculo) de pesque-pagues da microbacia do Córrego Rico, Jaboticabal (SP). Foram isoladas 115 cepas de E. coli, entre as quais 49 (43%) foram sorogrupadas como EPEC. Os sorogrupos mais frequentes foram O125, O126 e O158. Dentre as amostras testadas, 60 (52%) apresentaram resistência simultânea a dois antimicrobianos. A análise de correspondência foi realizada com o intuito de verificar as possíveis correspondências envolvendo o local de isolamento, sorogrupos e multirresistência e, com isso, pôde-se observar que o músculo apresentou menor correspondência com os demais fatores analisados. Porém, o isolamento de sorogrupos EPEC neste estudo representa risco à saúde dos consumidores.(AU)

The occurrence of Escherichia coli (EPEC, EIEC and O157) in water and fish (skin, gut and muscle) in pay-to-fish ponds of the micro bay of Córrego Rico, in Jaboticabal (SP), was assessed. One hundred and fifteen strains of E. coli were isolated, and 49 (43%) were serogrouped as EPEC. The most common serogroups were O125, O126 and O158. Among the tested samples, 60 (52%) showed simultaneous resistance to two antimicrobials. A correspondence analysis was performed to assess possible correlations involving the site of isolation, serogroups and multi-resistance. The results of this analysis showed that the muscle was less correlated with the the other factors. However, the isolation of EPEC serogroups in this study demonstrates a risk to public health.(AU)

Escherichia coli O157:H7: local epidemiology and disease spectrum in Brazil

Escherichia coli O157: H7 is one of the most important foodborne pathogens nowadays, since it has been responsible for severe outbreaks worldwide. Event hough this food pathogen has been isolated in many countries, Brazilian foods were considered E. coli O157:H7-free until recently. However, the presence of E. coli O157:H7 has been reported in diverse foods produced in Brazil and an increasing number of isolation from cattle feces has been observed, demonstrating that this pathogen is present in different parts of Brazil, and severe foodborne outbreaks mayoccur in the near future if adequate control measures are not implemented

[Presence and excretion of escherichia coli 0157: H7 by the livestock and their prevalence in the foodstuffs of animal origin]

Escherichia coli producing of Shiga-toxins and more particularly serogroupe 0157:H7 are currently recognized like pathogenic the emergent significant ones in public health. These bacteria were detected at a great number of animal species without the latter presenting clinical signs of disease. However, the principal tank seems to be the cattle population. The prevalence of E. coli 0157:H7 in the samples of deposit of the bovines varied from 4,8% to 36,8%. The persistence of the strains of STEC in the livestock is due, on the one hand, with the intestinal bearing by the animals, and on the other hand, with the contamination of the grounds and water starting from the animal manure being able to be at the origin of a contamination of food. Moreover, the persistence of germ in the animals depends on several factors to knowing: seasonal variation, mode of watering and food. The risk of contamination of the food products of animal origin is a function of the importance of the animal bearing, but also of the respect of the procedures of hygiene applied in particular in slaughter-house and in the workshops of transformation

importance of Escherichia coli 0157:H7 in foodborn infection

Enterohemorrhagic Escherichia coli O157: H7 is one of the most important causes of bloody diarrhea. This bacterium is able to make bloody diarrhea or Hemorrhagic Colitis [HC] through verotoxin or shigatoxin production, and in acute forms it may lead to Hemolytic Uremic Syndrome [HUS] or Thrombotic Thrombocytopenic Purpurea [TTP]. Contamination with E. coli O157:H7 usually happens after consumption of animal products especially undercooked meats. The most important reservoir of this bacterium is beef and consumption of undercooked ground beef, especially in children younger than 10 years old, is the most common reason of food infection by this bacterium. Two important biochemical characteristics for detection of E. coli O157: H7 are lack of sorbitol fermentation and absence of glucuronidase. In order to control food infection with this bacterium, foods must be cooked thoroughly until reaching the temperature of at least 68.3°C, in the center

[Frequency of enterohaemorrhagic Escherlchia coil isolated from patients with acute diarrhea in Tabriz hospitals]

Diarrhea is a major cause of morbidity in all age groups worldwide. Bacteria can cause 24% of infectious diarrhea which accounts for 70% mortality in affected children of <5 years old. Among the bacterial agents Salmonella spp, entero pathogenic E. coli, Campylobacter spp, Shigella spp and clostridia are the main causes of diarrhea. Escherichia coli O175 is an emerging cause of foodborne illness that presents with acute diarrhea. It transmits through the contaminated water, direct or indirect contact with animals and also through person to person contact. In addition to diarrhea, 2-7% of the patients infected with enterohemorrhagic E. coli [EHEC] will possibly develop haemolytic uremic syndrome [HUS] or acute renal failure. This study was conducted to determine the frequency of enteric pathogens with special reference to enterohaemorrhagic E. coli O157. A total of 1020 fecal specimens were collected from patients with acute diarrhea in Imam Khomeini and Children hospital of Tabriz. Direct examination was carried out for leukocytes, erythrocytes, parasite ova and trophozoites by wet mount preparation and the specimens also were cultured in selective and differential culture media for pathogenic bacteria. E. coli isolates were further typed using specific antisera and EHEC isolates were subjected to susceptibility testing against routinely used antibiotics. Entamoeba histolytica and Giardia lamblia were detected in 91[8.9%] and 51[5%] of cases. Pathogenic enteric bacteria were also isolated and recorded as E. coli O157 [n=6, 0.58%], E. coli O111 [n=15, 1.47%], E. coli O26 [n=13, 1.27%], Campylobacter jejuni [n=35, 3.4%], Salmonella spp. [n= 177 17.3%] and Shigella spp [9.5%]. All EHEC isolates were recovered from children <5 years old. In serological tests, 139 [13.5%] isolates of E. coli showed autoagglutination, which suggest their probable dependence to EAEC [entero aggregative E. coli]. Based on information collected from the EHEC positive patients' files, no sign of anemia or kidney disorder was detected. Entero pathogenic E. coli isolates are not usually tested in most of the routine diagnostic laboratories, so these medically important bacteria remain undiscovered, unless in an epidemic situation. Our findings of 3.3% enterohaemorrhagic E. coli and the presense of 0.58% E. coli O157 shows less frequency for these pathogenic bacteria and are in accordance with reports from other countries

Escherichia coli O157:H7 adherence to HEp-2 cells is implicated with curli expression and outer membrane integrity

Escherichia coli (E. coli) has ability to express thin aggregative fimbriae, known as curli, on the cell surface. Previously, a few example of curli expression in serogroup O157:H7 of enterohemorrhagic E. coli (EHEC) were reported, compared to other E. coli groups. However, significance of curliation in the EHEC pathobiology has not been described well in the literature. A highly curliated O157:H7 strain was used in this study in order to elucidate role of curliation in EHEC adherence to cultured HEp-2 cells. The expression of curli in the EHEC isolate was consistent with strong positive indication of Congo-red (CR) binding and formation of clumps in the bottom of the tube containing Luria-Bertani (LB) broth when cultured overnight at 37 degress C. A few CR-binding negative (CR-) colonies occurred spontaneously within the population of CR+ isolate. The CR+ EHEC showed massive aggregative adhesion pattern, whereas the spontaneous CR- strain showed typical localized adherence on HEp-2 cells. Electron microscopy confirmed highly curliated bacteria in the CR+ EHEC sample. Interestingly, the curliation disappeared in a msbB1 and msbB2 double mutant derived from the CR+ EHEC. These results suggest that the compromised outer membrane integrity caused by msbB mutations may abrogate curli production in the CR+ EHEC harbouring penta-acylated lipid A structure in their outer membrane.

Microangiopatías trombóticas: SUH/PTT: aspectos fisiopatológicos / Trombotic microangiopathies: SUH/PTT: physiopathological aspects

La causa y mecanismo de la lesión de la célula endotelial (CE) y el mecanismo que provoca la trombosis son los hechos fisiopatológicos más importantes y aún no totalmente conocidos como el Sindrome Urémico Hemolítico/Púrpura Trombocitopénica Trombótica (SUH/PTT). En el SUH asociado a Toxina de Shiga, la lesión de la CE es provocada por la toxina, que penetra a la célula a través de un receptor glicolipídico (Gb3) y altera la síntesis de proteínas celulares a nivel de los ribosomas, provocando la muerte celular por injuria o apoptosis. Existirían mecanismos que amplifican o facilitan la lesión endotelial por la toxina, a través de secreciones de citoquinas inflamatorias, activación de neutrófilos, etc. También se postula que existen factores condicionantes para la aparición de este síndrome, que podrían ser inmunológicos o genéticos. En las otras formas clínicas de SUH/PTT, idiopáticas, secundarias o familiares, tanto esporádicas como recurrentes, el mecanismo de la lesión de la CE no es conocido, pero pueden ser múltiples de acuerdo con cuál sea el cuadro clínico con el que se asocia (idiopático, infecciones, drogas, embarazo, enfermedades autoinmunes, etc.) También podrían existir mecanismos amplificadores de la lesión endotelial (citoquinas) y factores genéticos de predisposición, como el déficit de factor H del complemento en SUH familiar o esporádicos. En cuanto al mecanismo de la trombosis, la lesión o activación de la CE, al disminuir su tromborresistencia y aumentar su capacidad trombogénica, puede inducir la trombosis por múltiples mecanismos (activación de coagulación, activación plaquetaria e hipofibrinolisis). Se enfatizan las alteraciones de su membrana con disminución de los sistemas inhibidores de coagulación, expresión de Factor Tisular, disminución de los sistemas inhibidores de coagulación, expresión de Factor Tisular, disminución del sistema de ectoadepeasa (CD39), la liberación de FvW, etc., como mecanismos trombogénicos relevantes. Las modificaciones del FvW ("multímeros ultragrandes" o "multímeros pequeños") por una alteración en el clivaje de su molécula que genera multímeros con mayor afinidad y actividad agregante plaquetaria, es un mecanismo importante para mantener y aumentar el proceso trombótico, pero no parece ser el único mecanismo trombogénico en esta patología. La descripción reciente de "déficit congénito de la proteasa de FvW" en casos de PTT familiares y de déficit funcional de esta "proteasa"...

Influence of raw meat natural background flora on growth of Escherichia coli 0157: H7 in ground beef

Escherichia coli 0157 : H7 foodborne pathogen of increasing importance. It has been involved in several threatening outbreaks, most of them associated with meat products. In this study, the influence of some bacteria from the natural background flora of raw meat over E.coli 0157 : H7 in ground beef stored under refrigeration and at room temperature was evaluated. Different levels of E.coli 0157 : H7 (10 1 - 10 2, 10 3 - 10 4, and 10 6 - 10 7 CFU/g), inoculated in ground beef samples, were challenged with strains of non-pathogenic E.coli, Psudomonas putida or Leuconostoc sp. Growth of the pathogen was monitored using standard cultural methods and an Elisa-type rapid method. Non-pathogenic E.coli, Pseudomonas putida and Leuconostoc sp. did not affect growth of E.coli 0157 : H7 in ground beef, both under refrigeration and at room temperature. Based on these findings, the low occurrence of E.coli 0157 : H7 in raw meat may not be attributed to antagonistic effects of bacteria from the natural background flora.

Colitis hemorrágica por escherichia coli enterohemorrágica O157 H:7: comentario en relación a dos casos clínicos / Haemorrhagic colitis caused by escherichia coli H7-O157: a review of 2 clinical cases

Escherichia coli enterohemorrágica O157 H:7 es una infección emergente en nuestro país. Dos casos graves en nuestra unidad permiten actualizar aspectos poco conocidos. A diferencia de países desarrollados (edad media 15 años), en nuestro país afecta a niños pequeños (media 1,5 años) indicando probablemente transmisión doméstica desde el adulto, que no enferma por inmunidad. La colitis puede ser grave y requerir colectomía cuyas indicaciones no son precisas. No está comprobado que los antibióticos aumenten la incidencia de SHU pero se sugiere evitar su uso temprano. No todos los laboratorios clínicos buscan este germen aun cuando la técnica es fácil. El tratamiento debe incluir una observación cuidadosa buscando las complicaciones como síndrome hemolítico urémico y un manejo adecuado de contactos. La prevención se basa en buen lavado de utensilios de cocina en contacto con carne cruda, de las manos antes de tomar o alimentar niños, y la ingestión de carne de vacuno y cerdo bien cocida, en especial si es molida. Proposiciones: el médico debe buscar la etiología, y las autoridades difundir medidas de prevención e instaurar notificación obligatoria

Detección de citotoxinas de escherichia coli enterohemorrágica en productos cárnicos chilenos e importados / Detection of shiga-like toxin producing escherichia coli in chilean and imported meat products

Escherichia coli enterohemorrágica (ECEH) está catalogada como un patógeno emergente asociado al consumo de carnes contaminadas. Con el fin de establecer la importancia de los alimentos cárnicos chilenos e importados de venta libre en Santiago de Chile en la transmisión de infecciones por ECEH, se determinó la presencia de citotoxina stx1 y stx2 en dichos alimentos. Se analizaron 213 muestras cárnicas (157 chilenas y 56 importadas) por una prueba de inmunoensayo enzimático Premier, EHEC (Meridian Diagnostics Inc, Cincinnati, U.S.A.). Del total analizado, 9 (4,2 por ciento) muestras que correspondieron a 5 de carne de vacuno chilena, 2 de hamburguesas chilenas y 2 de carne de vacuno paraguaya, presentaron valores positivos a la presencia de citotoxina(s). De acuerdo a estos resultados, es necesario mantener el control microbiológico de ECEH en estos alimentos, con el fin de prevenir la aparición de brotes de intoxicación alimentaria en el país

Ocorrência de Escherichia coli O157: H7 em alimentos / Occurrence de Escherichia coli O157: H7 em alimentos

Escherichia coli O157:H7 foi reconhecida como um importante patógeno de origem alimentar no início dos anos 90, quando ocorreram vários surtos, principalmente nos Estados Unidos, envolvendo casos fatais, pelo consumo de produtos cárneos mal cozidos. E. coli O157:H7 provoca doenças graves, incluindo a colite hemorrágica e falhas renais (síndrome urêmica hemolítica). Vários outros, têm sido aplicados à análise rápida em alimentos. Alguns aspectos sobre o organismo, a doença, os alimentos envolvidos säo apresentados e os métodos de detecçäo säo discutidos neste trabalho de revisäo

Impacto del síndrome hemolítico urémico en las distintas áreas de salud de la Región Metropolitana / Impact of the uremic hemolytic syndrome in different health areas of the Región Metropolitana

El síndrome hemolítico urémico (SHU) constituye la causa más frecuente de insuficiencia renal aguda en lactantes y preescolares conocida en el mundo. En Chile, el diagnóstico de SHU ha tenido un aumento significatico en los últimos 10 años. A nivel internacional, el principal agente involucrado en la patogenia del SHU, es la Escherichia coli enterohemorrágica (ECEH, situación que también la hemos comprobado en nuestro país. Para conocer la magnitud del problema, como primer acercamiento, analizamos en el presente trabajo la tasa de incidencia anual de los casos más severos de SHU en la Región Metropolitana (RM), considerando a pacientes residentes en Santiago, que fueron atendidos en diferentes áreas de salud entre el 1 de enero de 1992 y el 31 de diciembre de 1994. En el período de estudio se registraron 61 casos de SHU en niños bajo 5 años de edad en la RM, lo que corresponde a una tasa de incidencia, de 3,26 por 100.000 niños de este grupo etario. El 82 porciente de los casos correspondió a niños entre 4 y 24 meses. Se observaron diferencias en las tasas de incidencia en las distintas áreas de salud, con un rango entre 7,3 y 0,86 por 100.000. En el área de salud Oriente se registró la tasa más elevada de casos de SHU y que fue significativamente mayor (p=<0,01) que en las restantes