Stx1 and Stx2 subtyping and antimicrobial resistance in Shiga toxin-producing Escherichia coli (STEC) isolates from cattle and sheep feces in the Southeastern region of the State of Goiás, Brazil / Subtipagem de Stx1 e Stx2 e resistência antimicrobiana em isolados de Escherichia coli produtoras de toxina Shiga (STEC) de fezes de bovinos e ovinos na região sudeste de Goiás, Brasil

The present study was aimed at subtyping of Stx1 and Stx2 genes and characterization of antimicrobial resistance in 106 Shiga toxin-producing Escherichia coli (STEC) strains isolated from cattle and sheep feces. PCR was used to determine the subtypes, and the disk-diffusion method was used to evaluate the antimicrobial resistance. Ten antibiotics from five different classes were tested. Among the isolates of bovine origin, two subtypes of Stx1 (Stx1a and Stx1c), and four subtypes of Stx2 (Stx2a, Stx2b, Stx2c, and Stx2d) were identified. In isolates of sheep origin, two subtypes of Stx1 (Stx1a and Stx1c), and four subtypes of Stx2 (Stx2a, Stx2b, Stx2c, and Stx2 g) were identified. The results obtained suggest the presence of high diversity in Stx1 and Stx2 genes. Further, 96.6% (57/59) of bovine fecal strains and 89.4% (42/47) of sheep fecal strains showed resistance to at least one tested antibiotic. In both animal species, most strains were multidrug-resistant (MDR) (67.8% in cattle and 59.6% in sheep), with no significant difference between host animals. Adult animals were eight times more likely to have STEC with greater pathogenic potential. STEC with the highest pathogenic potential were three times more likely to be multidrug-resistant than STEC with the lowest pathogenic potential. The data reported in this study suggests the occurrence of strains with high potential pathogenicity in the region studied. Therefore, the ruminants of this region are carriers of strains that can cause infections in humans.(AU)

O presente estudo teve como objetivo subtipar os genes Stx1 e Stx2 e caracterizar a resistência antimicrobiana em 106 isolados de Escherichia coli produtoras de toxinas Shiga (STEC) isoladas de fezes de bovinos e ovinos. A PCR foi utilizada para determinar os subtipos e o método de difusão em disco foi utilizado para avaliar a resistência antimicrobiana. Dez antibióticos de cinco classes diferentes foram testados. Entre os isolados de origem bovina, foram identificados dois subtipos de Stx1 (Stx1a e Stx1c) e quatro subtipos de Stx2 (Stx2a, Stx2b, Stx2c e Stx2d). Nos isolados de origem ovina, foram identificados dois subtipos de Stx1 (Stx1a e Stx1c) e quatro subtipos de Stx2 (Stx2a, Stx2b, Stx2c e Stx2g). Os resultados obtidos sugerem a presença de alta variabilidade nos genes Stx1 e Stx2. Além disso, 96,6% (57/59) dos isolados fecais de bovinos e 89,4% (42/47) dos isolados de ovinos mostraram resistência a pelo menos um antibiótico testado. Em ambas as espécies animais, a maioria das cepas foi multirresistente (MDR) (67,8% em bovinos e 59,6% em ovinos), sem diferença significativa entre as espécies animais do reservatório. Os animais adultos tiveram oito vezes mais chances de apresentar STEC com maior potencial patogênico. STEC com o maior potencial patogênico teve três vezes mais chances de ser multirresistente do que o STEC com o menor potencial patogênico. Os dados relatados neste estudo sugerem a ocorrência de cepas com alto potencial de patogenicidade na região estudada. Portanto, os ruminantes dessa região são hospedeiros de isolados que podem causar infecções em humanos.(AU)

Síndrome hemolítico urémico asociado a Shigatoxina: ¿Cómo prevenirlo? / Shiga-toxin associated hemolytic uremic syndrome: how to prevent it?

Resumen: El síndrome hemolítico urémico (SHU) asociado a infección intestinal por bacterias productoras de Shigatoxina, que afecta principalmente a población infantil, puede causar morbilidad aguda grave, secuelas crónicas en varios órganos, y la muerte prematura en algunos de ellos. Dado su carácter zoonótico, adecuadas medidas de manejo agropecuario y correcta higiene de lo que consumimos es indispensable a la hora de prevenir la infección. Actualmente, una vez gatillado el SHU el manejo es médico y, principalmente, de soporte. En los últimos años diversas estrategias terapéuticas se han ido desarrollando para evitar que esta enfermedad ocurra, o, al menos, que pueda ser atenuada en sus consecuencias de morbi-mortalidad. El presente artículo describe acciones específicas a diferentes niveles de prevención de esta patología.

Abstract Hemolytic uremic syndrome (HUS) associated with intestinal infection by Shiga toxin-producing bacteria, which mainly affects children, can cause severe acute morbidity, chronic sequelae in seve ral organs, and premature death in some of them. Given its zoonotic nature, adequate measures of agricultural management and proper hygiene of what we consume are essential to prevent infection. Once the HUS is triggered, medical management is currently mainly supportive. In recent years, va rious therapeutic strategies have been developed to prevent this disease from occurring or, at least, to mitigate its morbidity and mortality consequences. This article describes specific actions at different levels of prevention of this pathology.

Prevalence and molecular characterization of Shiga toxin-producing Escherichia coli isolates from human and sheep in Al-Madinah Al-Munawarah / Prevalencia y caracterización molecular de cepas de Escherichia coli productoras de toxina Shiga en seres humanos y ovejas de Al-Medina Al-Munawarah

Shiga toxin-producing Escherichia coli (STEC) strains have emerged as important foodborne pathogens of global public health concern, causing life-threatening diseases. Sheep and their products have been documented as important reservoirs for STECs, especially E. coli O157. The aim of this study was to investigate STECs from diarrheal human and sheep in Al-Madinah Al-Munawarah, Saudi Arabia. Fecal samples were collected between June and August, 2015 from diarrheal humans (n = 134) and sheep (n = 87). Presumptive E. coli human-and sheep-isolated strains were identified for their serotypes, the associated virulence genes (Shiga toxin [stx1 , stx2 ], haemolysin [ehxA] and intimin [eae]) by polymerase chain reaction and their susceptibility to antibiotics. Pulsed-field gel electrophoresis (PFGE) was used to demonstrate the genetic relatedness between Serotype O157:H7 human- and sheep-isolated strains. Forty eight (48/221; 21.7%) STECs were recovered from both human and sheep, their serotypes were as follows: O157:H7, O26:H11, O157:HNM, O26:HNM, O128:H2, O48:HNM, O111:HNM and OUT:HUT. Various virulence profiles and multiple antibiotic resistance were observed among the isolates. Twenty eight O157:H7 serotypes (17 human isolates and 11 sheep isolates) were identified in 13 PFGE pulsotypes, where human and sheep isolates were highly related. PFGE banding profiles together with serotypes and genotypes afford proof that human and sheep can be colonized and infected with similar E. coli O157:H7 strains. Our findings highlight the importance of epidemiological and microbiological surveillance of STECs; as well as the development of control measures to decrease risks associated with zoonotic O157:H7.

Las cepas de Escherichia coli (E. coli) productoras de toxina Shiga (STEC, del inglés Shiga toxin-producing E. coli) han surgido como importantes agentes patógenos de origen alimentario que son motivo de preocupación para la salud pública mundial, ya que provocan enfermedades potencialmente mortales. Se ha confirmado que las ovejas y sus productos son reservorios importantes para la STEC, especialmente E. coli O157. El objetivo de este estudio fue investigar STEC procedentes de deposiciones diarreicas humanas y ovinas en Al-Medina Al-Munawarah (Arabia Saudí). Se recogieron muestras fecales entre junio y agosto de 2015 de deposiciones diarreicas humanas (n = 134) y ovinas (n = 87). Se identificaron las presuntas cepas de E. coli humanas y ovinas por sus serotipos, los genes de virulencia asociados (toxina Shiga [stx1, stx2], hemolisina [ehxA] e intimina [eae]) por reacción en cadena de la polimerasa y la susceptibilidad a los antibióticos. Se utilizó la electroforesis en gel de campo pulsado (EGCP) para demostrar el parentesco genético entre el serotipo O157:H7 de las cepas humanas y el de las ovinas. Se aislaron 48 STEC (48/221; 21,7%) tanto humanas como ovinas y sus serotipos fueron los siguientes: O157:H7, O26:H11, O157:HNM, O26:HNM, O128:H2, O48:HNM, O111:HNM y OUT:HUT. Entre las cepas se observaron varios perfiles de virulencia y resistencia a múltiples antibióticos entre los aislamientos. Se identificaron 28 serotipos O157:H7 (17 cepas humanas y 11 cepas ovinas) en 13 pulsotipos de la EGCP, en los que las cepas humanas y ovinas estaban sumamente vinculadas. Los perfiles de bandeos de la EGCP, junto con los serotipos y genotipos, ofrecen una prueba de que seres humanos y ovejas pueden ser colonizados e infectados por cepas similares de E. coli O157:H7. Nuestros resultados destacan la importancia de la vigilancia epidemiológica y microbiológica de STEC, así como del desarrollo de medidas de control para reducir los riesgos asociados con la O157:H7 zoonótica.

Avaliação da capacidade de formar biofilme de Escherichia coli produtoras de shiga toxina / Biofilm-forming ability of shiga toxin-producing Escherichia coli / Evalución de la capacidad de formar biopelícula de Escherichia coli productoras de toxina shiga

O objetivo deste trabalho foi avaliar a formação de biofilme por cepas de Escherichia coli produtoras de shiga toxina (STEC) previamente isoladas de fezes de bovinos de corte e de leite no sul do Rio Grande de Sul, Brasil. 165 cepas foram cultivadas nas cavidades de placas de microtitulação, lavadas, retirado o sobrenadante e coradas. Após, a absorbância medida em cada cavidade foi comparada com controles negativos e positivos. Nenhuma das cepas de STEC isoladas de fezes de bovinos do sul do Brasil analisadas neste estudo apresentou capacidade de formar biofilme.

This study evaluated the biofilm-forming ability of shiga toxin-producing Escherichia coli (STEC) strains previously isolated from beef and darry cattle in Rio Grande do Sul, Brazil. 165 strains were grown in wells of microtiter plates, washed, the supernatant removed and stained. After, the absorbance in each well compared with negative and positive controls. None of the STEC strains isolated from feces of cattle in Southern Brazil analyzed in this study showed the ability to form biofilm.

El objetivo de este estudio fue evaluar la formación de biopelícula por cepas de Escherichia coli productoras de toxina Shiga (STEC), previamente aisladas de heces de ganado de carne y de leche, en el sur de Rio Grande do Sul, Brasil. 165 cepas han sido cultivadas en las cavidades de placas de microtitulación, lavadas, retirado el sobrenadante y coloradas. Después, la absorbencia medida en cada cavidad fue comparada con controles positivos y negativos. Ninguna de las cepas STEC aisladas de heces de ganado, en el sur de Brasil, analizadas en este estudio, demostró la capacidad de formar biopelí-cula.

Analysis of etiological surveillance results of Shigella spp between 2009 and 2010 in Henan province / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the etiologic characteristics of bacillary dysentery found in Henan province, between year 2009 and 2010.</p><p><b>METHODS</b>In order to explore the distribution of bacterial types, drug susceptibility and the virulence gene carrier situation, 482 strains of Shigella isolated in Henan province between 2009 and 2010 were pathogen-detected and analyzed by serotype screening, anti microbial sensitivity test and PCR methods.</p><p><b>RESULTS</b>The 482 isolated strains were confirmed to be Shigella by both morphological and biochemical tests. The Shigella strains were divided into 13 serotypes in 2 groups, namely Shigella flexneri (B group) accounting for 72.0% (347/482) and Shigella sonnei (D group), accounting for 28.0% (135/482). The detection rate of Serotype F2a, as the dominant type of Shigella flexneri, decreased from 43.4% (106/245) in 2009 to 33.8% (80/237) in 2010; while the detection rate of Shigella sonnei increased from 13.1% (32/245) to 43.5% (103/237) in the same period. The results of microbial sensitivity tests carried out in year 2009 and 2010, both showed that over 98% of the 185 studied strains were resistant to ampicillin (AMP), trimethoprim-pyrimidine (TMP), tetracycline (TE), streptomycin (S) and nalidixic acid (NA).182 strains were recruited in the virulence factors detection, 67.6% (123/182) of which carried Shigella Enterotoxin 1B (set1B), Shigella Enterotoxin 2 (set2), invasive plasmid antigen H (ipaH) or invasion-related virulence factors (ial) and 24.2% (44/182) of which carried 3 virulence factors mentioned above.</p><p><b>CONCLUSION</b>The prevalent serotypes of Shigella in Henan province have changed in recent years. The isolated strains showed high resistance to common antibacterial drugs and generally carried virulence factors.</p>

Avaliação da interação de Escherichia coli enterohemorrágica (EHEC) pertencente ao sorotipo O157: H7 isoladas de bovinos assintomáticos e de doença humana com células enterocíticas humanas (linhagem Caco-2) / Evaluation of interaction of Enterohaemorrhagic (EHEC) 0157: H7 isolated from asymptomatic cattle and human disease with human enterocitic cells

Reconhecida como agente de doença humana em 1982, E.coli enterohemorrágica (EHEC) pode causar diarréia sanguinolenta, colite hemorrágica e síndrome hemolítica urêmica (SHU). EHEC constitui um subgrupo especialmente virulento das E.coli produtoras de toxina de Shiga (Stx). O fator crítico da sua virulência é a toxina Shiga, capaz de interromper a síntese proteica da célula eucariótica. São conhecidos dois subgrupos de Stx, Stx1 e Stx2. Stx1 possui duas variantes Stx1c e Stx1d. Stx2 possui muitas variantes. Estudos epidemiológicos sugerem que cepas com os perfis toxigênicos Stx2 ou Stx2/Stx2c seriam mais frequentemente associadas a pacientes com SHU. Além da expressão de Stx, EHEC do sorotipo O157:H7 colonizam a mucosa intestinal induzindo a formação de lesões denominadas ‘attaching/effacing’ (A/E). Para a produção da lesão A/E, é necessária a presença de uma ilha de patogenicidade cromossômica denominada LEE, composta por cinco operons, LEE 1 a LEE5. Em LEE 5 são codificadas a adesina intimina e o seu receptor Tir, o qual é translocado por um sistema de secreção tipo III (SSTT) e em LEE 4 são codificadas as proteínas secretadas EspA,B e D. Em EHEC O157:H7 são descritos muitos fatores de virulência, codificados em ilhas de patogenicidade, no cromossomo e no megaplasmídio pO157. Bovinos são o principal reservatório deste patógeno e alimentos de origem bovina e produtos contaminados com fezes de bovinos são causadores de surtos epidêmicos. Em nosso país EHEC O157:H7 é isolada do reservatório animal mas é muito rara a sua ocorrência em doença humana. Notamos que nas cepas bovinas predomina Stx2c, enquanto nas cepas humanas predomina o perfil toxigenico Stx2/Stx2c...

Recognized in 1982 as a human pathogen, enterohemorrhagic Escherichia coli (EHEC) causes bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). EHEC belonging to serotype O157:H7 are mostly important in North America, United Kingdom and Japan. Shiga toxin (Stx) is the critical factor of STEC. Stx is capable to interrupt the protein synthesis of the eukaryotic cell. Two subgroups of Stx are known, Stx1 and Stx2. Two variants of Stx1 are known (Stx1c and Stx1d), but several Stx2 variants have been described. Epidemiological studies suggest that STEC/EHEC strains carrying the toxigenic profiles Stx2 or Stx2/Stx2c are more frequently associated to HUS. Besides the expression of Stx, EHEC O157:H7 colonize the intestinal mucosa inducing the formation of characteristic histopathological lesions denominated “attaching/effacing” (A/E). To the production of A/E lesions, it is necessary the presence of a pathogenicity island called LEE (locus of enterocyte effacement), composed by five operons, LEE 1 to LEE5. An outer membrane adhesin (intimin) and its receptor Tir, which is translocated by a type three secretion sytem (TTSS), are both codified in LEE5 while the secreted proteins EspA, B and D, that constitute part of the SSTT, are codified in LEE4. Cattle are the main reservoir of this pathogen and foods of bovine origin and products contamined with bovine feces are common causes of epidemic outbreaks. In Brazil, EHEC O157:H7 can be isolated from the animal reservoir . Stx2c prevails among the bovine strains, while the toxigenic profiles Stx2 or Stx2/Stx2c are found among the human strains...

Identification & characterization of Shiga toxin-producing Escherichia coli isolates from patients with diarrhoea in Iran.

Background & objectives: Verotoxigenic Escherichia coli are important serotypes of enterohaemorrhagic E. coli (EHEC) subgroup that cause attaching and effacing lesions in enterocytes by producing verotoxins or shiga-like toxins resulting in haemorrhagic colitis (HC) and haemolytic uremic syndrome (HUS). The aim of this study was to detect these serotypes specially E. coli O157:H7 in stool samples of patients with diarrhoea and identification of virulence genes (STX1, STX2, Hly and EAE) in Shahrekord-Iran area using PCR technique. Methods: Two hundred diarrhoeal stool samples of patients were collected through 2007-2008. Microbiological and biochemical examinations were done to detect the E. coli. Serological tests carried out to identify the O157 or O157:H7 serotypes. Results: Of the 58 E. coli isolates, 16 (27.6%) were detected as STX1 carrying E. coli, four (6.9%) carrying STX2, eight (13.8%) carrying both STX1 and STX2, and 12 (20.7%) were Hly carrying E. coli, but none of the isolates contained EAE gene. None of the isolates were E. coli O157 or O157:H7 serotypes. Interpretation & conclusions: Our results revealed that verotoxigenic E. coli isolates other than O157 serotype were involved in causing diarrhoea in Shahrekord-Iran.

Aislamiento de Escherichia coli O145: NM en casos de síndrome urémico hemolítico / Escherichia coli 0145-. NM isolated from hemolytic uremic syndrome cases

En Argentina se notifican más de 500 nuevos casos de síndrome urémico hemolítico (SUH) anuales. El objetivo del trabajo fue investigar epidemiológicamente casos de SUH y contactos de los que se aislaron cepas de STEC O145:NM que pertenecían a un mismo cluster. Para detectar STEC se realizó PCR-múltiple para amplificar genes de toxinas Shiga 1 y 2, y otros marcadores de virulencia como eae y ehxA. Se subtipificó STEC por separación por electroforesis de campos pulsados (XbaI-PFGE). Entre enero y febrero de 2006, en tres casos de SUH y un contacto familiar conviviente se identificó STEC O145:NM. Genotípicamente se caracterizaron como productores de stx2, eae+ y ehxA+. Todas las cepas presentaron el mismo patrón por XbaI-PFGE (AREXSX0 1.0207) y por B/nI-PFGE (AREXSA26.0018). Estas cepas pertenecieron a un mismo cluster, diseminado en distintos barrios de la ciudad de Mar del Plata. Los datos de la investigación epidemiológica fueron incompletos para establecer un nexo entre los casos. Sin embargo, no se descarta la posibilidad de ocurrencia de un brote difuso. Se destaca la importancia que tiene el sistema de vigilancia de laboratorio en tiempo real mediante PFGE como mecanismo de alerta que sirve para afianzar los resultados con los datos de epidemiología.

More than 500 new cases of hemolytic uremic syndrome (HUS) are annually reported in Argentina. The aim of this work was to carry out epidemiological studies on cases of HUS and their household contacts that were isolated from STEC O145 strains: NM belonging to the same cluster. In order to detect STEC, Multiplex PCR was performed to amplify Shiga toxin 1 and 2 genes and other virulence markers like eae and ehxA. STEC was subtypified by means of separation by pulsed field electrophoresis (PFGE-XbaI). Between January and February 2006, STEC O145:NM strains were identified in three cases of HUS and one household contact. Genotypically, they were characterized as producing stx2, eae+ and ehxA +. All strains showed the same pattern by PFGE-XbaI (AREXSX01.0207) and BlnI-PFGE (AREXSA26.0018). These strains belonged to the same cluster, scattered in different areas of the city of Mar del Plata. Data from epidemiological research were not enough to establish a link between the cases. However, the possibility of occurrence of a diffuse outbreak. is not ruled out The importance of a laboratory surveillance system in real time by PFGE is stressed, as a warning mechanism that serves to strengthen the results with epidemiologic data.

A Case of Verotoxin-producing Escherichia coli O157:H7 with Hemorrhagic Colitis in an Infant, Diagnosed by Multiplex PCR / 대한임상미생물학회지

Enterohemorrhagic Escherichia coli (EHEC) is an important cause of bloody diarrhea in children, but is considered to be rare in infants. Herein, a case of infant hemorrhagic colitis of verotoxin-producing E. coli O157:H7 diagnosed by multiplex PCR is reported. A nine-month-old boy was admitted to our hospital with bloody diarrhea for the previous two days. Multiplex PCR using Seeplex(R) Diarrhea ACE Detection Kit (Seegene, Seoul, Korea) was directly applied to the stool specimens. Amplified bands specific for verotoxin, O157, and H7 indicated the presence of O157:H7 EHEC. The stool specimens were inoculated on sorbitol-MacConkey agar (SMA) and tryptic soy broth containing mitomycin C (TSB-M). Colorless colonies on sorbitol-MacConkey agar were O157-positive. TSB-M enrichment cultures of the stool specimen and the isolates were positive for verotoxin according to an enzyme immunoassay (EIA). The prepared ingredients of baby foods for the patient including ground meat, chopped carrot, chopped cabbage, and white rice porridge showed no EHEC on TSB-M and SMA. The patient's parents and three-year-old sister did not recently have any gastrointestinal symptoms. Cefdinir was administered for one day and was ceased after diagnosis of EHEC colitis. The stool culture and verotoxin assay were negative on the second day of hospitalization. Application of multiplex PCR and verotoxin EIA directly to diarrheal stool warrants the rapid diagnosis and appropriate treatment of EHEC colitis.

Studies on Shiga-toxins [STX1 and STX2] produced by escherichia coli isolated from diarrheal cases in Assiut university children hospital

Shiga toxin producing E. coli. [STEC] are emerging pathogens capable of producing sporadic and epidemic diarrhea that may be complicated by haemorrhagic colitis and life threatening hemolytic uremic syndrome [HUS]. The goals of the present study is testing stool specimens for Shiga toxins [Stx1 and Stx2] and detection of the prevalence of the Shiga toxin producing E. coli [STEC] among the diarrheal cases collected in Assiut University Children Hospital. For these purposes, stool specimens from 150 inpatients and 150 outpatients with diarrhea, watery diarrhea or bloody diarrhea and from 40 infants and children with no gastrointestinal illness as control were collected from Assiut University Children Hospital. Escherichia coli was detected in 30 [20%], 64 [42.67%] and 12 [30%] of the inpatients, outpatients and control group respectively. The detection of the Shiga toxins [verotoxins] was done by phenotypic method [Vero cell cytotoxicity assay], immunological method [EIA using RIDA screen kit] and finally by genotypic method [multiplex PCR]. During our study, multiplex PCR [as gold standerd] showed that 4 [13.33%] and 17[26.56%] of E. coli isolated from the inpatients and outpatients respectively were STEC. Non of the E. coli isolateded from control group were STEC. Seven [33.3%] of STEC isolates carried Shiga toxin 1 [Stx1] genes and 14 [66.7%] of STEC isolates carried Shiga toxin 2 [Stx2] genes

Síndrome hemolítico urémico asociado a infección por E. coli productor de toxina de shiga / Shiga-toxin-producing Escherichia coli and haemolytic uraemic syndrome

E.coli productora de Toxina Shiga (STEC), también conocida como E.coli entero- hemorrágica (EHEC), provoca un amplio espectro de manifestaciones clínicas, ya sea en brote o en forma esporádica, que incluyen dolor abdominal, fiebre leve o ausente, con o sin vómitos, diarreas (sanguinolenta o no), y complicaciones extraintestinales como: síndrome hemolítico urémico (SHU) que se observa hasta en un 5-6 por ciento de niños infectados, y púrpura trombocitopénico (7 por ciento de adultos). EI principal factor de virulencia es la producción de una familia de moléculas denominada STX (Shiga toxin), de las cuales STX 1 y 2 son las más frecuentes y característica distintiva de estos E.coli. EI principal serogrupo involucrado en Chile es O157:H7 pero también se han aislado 026, 055, 02, 0117 y 06 (generalmente clasificadas como E. coli serogrupo clásico, no enterohemorrágico). Es fundamental para el clínico conocer la epidemiología, sintomatología y los exámenes que permitan un diagnóstico rápido para manejo terapéutico adecuado, y así evitar las complicaciones enunciadas anteriormente.

Shiga toxin producing E.coli (STEC), also known as enterohemorragic E.coli (EHEC), are responsible for a wide variety of clinical manifestations, both epidemic and sporadic. These include abdominal pain, no fever to mild fever, with or without vomits, diarrhea (bloody or not) and extraintestinal complications, such as haemolytic uremic syndrome in about 5 to 6 percent of children, and trombocitopenic purpura in 1 percent adults. The main virulence factor involved is the production of STX (Shiga toxin). In Chile there is marked prevalence of E.coli serogroup 0157 :H7 in these cases, although it has been associated also to E.coli 026, 055,02,0117 and 06, considered as classic serogroup (not enterohemorragic). It is of outmost importance for clinicians to be aware of symptoms and signs of this disease, as well as diagnostic methods that allow a prompt and adequate treatment, in order to avoid complications.

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

All blood, No stool: enterohemorrhagic Escherichia coli O157:H7 infection

Enterohemorrhagic Escherichia coli serotype O157:H7 is a pathotype of diarrheagenic E. coli that produces one or more Shiga toxins, forms a characteristic histopathology described as attaching and effacing lesions, and possesses the large virulence plasmid pO157. The bacterium is recognized worldwide, especially in developed countries, as an emerging food-borne bacterial pathogen, which causes disease in humans and in some animals. Healthy cattle are the principal and natural reservoir of E. coli O157:H7, and most disease outbreaks are, therefore, due to consumption of fecally contaminated bovine foods or dairy products. In this review, we provide a general overview of E. coli O157:H7 infection, especially focusing on the bacterial characteristics rather than on the host responses during infection.

A Case of Escherichia coli O157 Hemorrhagic Colitis / 대한임상미생물학회지

Escherichia coli O157 is an important serotype of enterohemorrhagic E. coli that causes hemorrhagic colitis worldwide. Outbreaks of E. coli O157 have been assocoated with contaminated food like meat, raw milk, and water, but recently vegetables and fruits have accounted for a growing number of recognized outbreaks. We isolated verotoxin producing E. coli O157 from the stool of a 3 year-old female with bloody diarrhea and abdominal pain. The child had been eating salad with vegetables and fruits frequently.

Escherichia coli produtora de toxina shiga (STEC): principais fatores de virulência e dados epidemiológicos / Shiga toxin-producing Escherichia coli (STEC): principal virulence factors and epidemiology

Escherichia coli produtora de toxina Shiga (STEC) é um importante patógeno veiculado por alimentos, principalmente produtos derivados de carne bovina e está associado a quadros de diarréias leves a severas e sanguinolentas. Em alguns indivíduos, a infecção por STEC pode progredir para a síndrome hemolítico-urêmica (HUS), seqüela caracterizada pela falência renal e a púrpura trombocitopênica trombótica (TTP), com possível envolvimento do sistema nervoso central. O gado bovino, geralmente saudável, é o principal reservatório de STEC, embora estas cepas também tenham sido isoladas de outros animais domésticos: ovelhas, cabras, cães, gatos e suínos. A principal característica de virulência, a produção de toxinas Shiga, não é suficiente para causar doenças e outros fatores são considerados relevantes, como a produção de nterohemolisina e de adesinas fimbriais e afimbriais. Embora as doenças humanas associadas a STEC sejam pouco descritas no Brasil, podemos observar uma significativa ocorrência destas cepas nos rebanhos bovinos, bem como a correlação entre sorotipos encontrados nestes animais e em pacientes humanos.

Shiga toxin producing Escherichia coli is an important food borne pathogen, mainly beef products, andis associated to mild and severe bloody diarrhea. In some individuals, STEC infection can progress tohemolytic-uremic syndrome (HUS), a sequela characterized by renal failure, and thrombotic thrombocytopenic purpura (TTP), with possible central nervous system involvement. Cattle, usually healthy, is the principal reservoir of STEC, although these strains have also been isolated from other domestic animals: sheep, goats, dogs, cats and pigs. The principal virulence feature, the production of Shiga toxins, is not enough to cause diseases, and other factors are considered important, as enterohemolysin and fimbrial and afimbrial adhesions production. Although human diseases associated to STEC have not been frequently reported in Brazil, their presence is frequent in cattle, as well as the correlation between serotypes found in these animals and human patients.

Patient and sample-related factors that effect the success of in vitro isolation of Orientia tsutsugamushi.

Orientia tsutsugamushi is the causative agent of scrub typhus infection, a major cause of human disease in rural areas of Southeast Asia. Twenty-six blood samples collected from patients with serologically proven scrub typhus during a six month period were sent to Bangkok (535 km from the clinical site) by road at ambient temperature (average daily temperature range: 27.1-29.1 degrees C) for attempted in vitro isolation in Vero cells. O. tsutsugamushi was isolated from 12 samples (sensitivity 46.7%) with the time to isolation ranging from 16 to 37 days [median 27 days, inter-quartile range (IQR) 22.5-33.5 days]. Patient factors such as days of fever and O. tsutsugamushi IgM antibody titer, transport factors such as transit time, and isolate genotype (Karp and Gilliam/Kawasaki) were assessed to determine their influence on the outcome of in vitro isolation. None of the factors significantly influenced the isolation outcome. This study demonstrates that O. tsutsugamushi can often be isolated in vitro from the blood of scrub typhus patients when transported at ambient tropical temperatures for many days.

Papel de la Toxina Shiga en el sindrome urémico hemolítico / Role of the Shiga toxin in the hemolytic uremic syndrome

In the last years, infection associated with Shiga toxin-producing Escherichia coli (STEC) and subsequent Hemolitic-Uremic Syndrome (HUS) became relevant as a public health since it was considered as one of the most important emergent patogen present in the food contaminated by cattle feces. STEC infection may be asymptomatic or begins with a watery diarrhea that may or may not progress to bloody diarrhea (hemorrhagic colitis) and HUS. In Argentina, HUS is the most common pediatric cause of acute renal insufficiency and the second cause of chronic renal failure. Up to now, STEC infection lacks of known effective treatment strategies that diminish risk of progression to HUS. The mechanisms by which Shiga toxin (Stx) induce HUS may help to find strategies to prevent or ameliorate HUS. In this article, recent progress that has contributed to understanding the disease pathogenesis of STEC is reviewed. New strategies to prevent further uptake of Shiga from the gut, either during the diarrheal phase or once HUS has developed are discussed.

Epidemiologia del síndrome urémco hemolítico en Argentina: diagnóstico del agente etiológico, reservorios y vías de transmissión / The epidemiology of hemolytic uremic syndrome in Argentina. Diagnosis of the etiologic agent, reservoirs and routes of transmission

Shiga toxin-producing Escherichia coli (STEC) cause sporadic cases and outbreaks of nonbloody and bloody diarrhea, and hemolytic uremic syndrome (HUS). E. coil O157:H7 is the most prevalent STEC serotype. However, other serotypes (O26:H11; O103:H2; O111:NM; O121:H19; O145:NM, among others) can cause a similar disease spectrum. Shiga toxins (Stx1, Stx2, and their variants), intimin, and enterohemolysin are the main virulence factors. Three different diagnostic criteria are used to determine the frequency of STEC infection: 1) isolation and characterization of STEC strains; 2) detection of specifically neutralizable free fecal Stx; and 3) Serological tests to detect Stx-antibodies. The surveillance of the STEC strains is performed using subtyping techniques: a) genotyping of Stx and eae by PCR-RFLP; b) phage typing of E. coil O157 strains; and c) pulsed-field gel electrophoresis. STEC O157 and non-O157 strains are recovered from clinic, animal, food and environmental samples, and E. coli O157:H7, a Stx2 and Stx2c producer, harboring eae and ehxA genes, is the most common serotype. During a prospective case-control study conducted to evaluate risk factors for sporadic STEC infection in Mendoza Province and Buenos Aires City and its surroundings during 2001-2002, exposures associated with risk included eating undercooked beef, contact with a child < 5 years with diarrhea and living in or visiting a place with farm animals. Both washing hands after handling raw beef, and eating fruits and vegetables were frequently protective. Strategies of prevention and control are necessary to decrease the incidence of STEC infections in Argentina.

Escherichia coli produtora de toxina Shiga (STEC): marcadores de virulência e análise clonal / Shiga toxin-producing Escherichia coli(STEC): virulence markers and clonal analysis

Foi estudada uma coleção de 48 cepas de Escheríchía cali produtoras de toxina Shiga (STEC), a maioria de origem humana, e 30 cepas de E. cali não STEC de origem humana, portadoras da seqüência eae e pertencentes aos mesmos sorogrupos de STEC, isoladas no período entre 1976-03. Foram analisadas as características fenotípicas, os fatores de virulência e a diversidade genética. A maioria das cepas STEC originou de estudos realizados em dois períodos distintos: um estudo retrospectivo incluindo o período 1976-99 e um estudo prospectivo desenvolvido no período 2000-03. Excetuando duas cepas isoladas do mesmo paciente durante o estudo prospectivo, todas as cepas de origem humana eram de infecções esporádicas e não relacionadas. Entre os diferentes sorotipos de STEC identificados, a maioria pertencia aos sorotipos 0111:H-, 0111:H8, 026:H11 e 0157:H7. Observou-se, no entanto, uma variação em relação a ocorrência dos sorotipos STEC não-0157 no período estudado. Enquanto os sorotipos 0111 :H8 (H-) e 026:H11 predominaram entre aquelas isoladas no período 1976-99, no período 2000-03 foi identificada apenas uma cepa STEC 0111:H-. A ausência de fermentação da ramnose e dulcitol estava mais associada às cepas STEC e não STEC pertencentes ao sorogrupo 026, enquanto que as cepas STEC do sorogrupo 0111 se distinguiram por não descarboxilar a lisina. A maioria das cepas STEC foi sensível a todos os antimicrobianos testados; porém múltiplas marcas de resistência foram observadas, principalmente, em algumas cepas do sorogrupo 0111. Todas as cepas STEC 0157:H7 eram portadoras do gene stx2. Cepas pertencentes aos sorotipos 093:H19 e 077:H18, pertenciam ao genótipo stx1 stx2, enquanto que os demais sorotipos STEC carreavam apenas a seqüência stx 1. A seqüência eae foi identificada em todas as cepas STEC, exceto entre aquelas pertencentes aos sorotipos 093:H19, 077:H18 e 055:H19 e observou-se uma estreita relação entre os tipos de intimina, sorotipos e categoria diarreogênica. A presença da seqüência ehxA foi variável segundo os sorotipos. Com exceção do sorogrupo 026, as cepas STEC e não STEC do mesmo sorogrupo pertenciam a distintos grupos clonais determinado pela técnica de eletroforese em campo pulsado. Observou-se que cepas STEC com distintas características fenotípicas e genotípicas, estavam presentes em nosso meio desde a década de 70 e as características moleculares apontaram para uma provável ocorrência de um surto de infecção O157:H7.