First report of the prevalence of Shiga toxinproducing Escherichia coli in ground beef in Quindío, Colombia

Introduction. Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen associated with clinical cases of diarrhea in humans. Its main virulence factors are the Shiga toxins (Stx1 and Stx2). Cattle are the main reservoir of STEC, and many outbreaks in humans have been related to the consumption of undercooked ground beef contaminated with this pathogen. Objective. To determine the prevalence of STEC in ground beef commercialized in all the butcher shops of a township in the department of Quindío and to characterize the virulence genes of the strains found. Materials and methods. Thirty ground beef samples were taken in three different times; stx genes and other STEC virulence factors (eae, ehxA, saa) were detected by multiplex PCR. Results. The overall prevalence of STEC was 33.33 % (10/30 positive samples). We isolated eight non-O157 (LEE-negative) strains with four different genetic profiles: stx 2 / stx 2-ehxA-saa / stx 1-stx 2-ehxA-saa / stx 1-saa. Conclusion. This is the first report on the prevalence of STEC in ground beef in a township in the department of Quindío.

Introducción. Escherichia coli productora de toxina Shiga (STEC) es un agente patógeno de origen alimentario asociado a casos clínicos de diarrea en humanos; sus principales factores de virulencia son las toxinas Shiga (Stx1 y Stx2). El principal reservorio de STEC es el ganado bovino y muchos brotes en humanos se han relacionado con el consumo de carne mal cocida contaminada con este agente patógeno. Objetivo. El objetivo de este trabajo fue determinar la prevalencia de STEC en carne molida comercializada en todas las carnicerías de un municipio del departamento del Quindío y caracterizar los genes de virulencia de las cepas encontradas. Materiales y métodos. Se tomaron 30 muestras de carne molida en tres momentos diferentes; se detectaron los genes stx y otros factores de virulencia de STEC (eae, ehxA, saa) mediante PCR Multiplex. Resultados. Los resultados mostraron una prevalencia global de STEC del 33,33 % (10/30 muestras positivas). En total se aislaron ocho cepas STEC no-O157 (LEE-negativas) con cuatro perfiles genéticos diferentes: stx 2 / stx 2-ehxA-saa / stx 1-stx 2-ehxA-saa / stx 1-saa. Conclusión. Este es el primer reporte que muestra la prevalencia de STEC en carne molida en un municipio del departamento del Quindío.

Research Advances on the Pathogenesis and Treatment of Hemolytic Uremic Syndrome --Review / 中国实验血液学杂志

Hemolytic uremic syndrome (HUS) is clinically rare, with high mortality and case fatality rates. In recent years, the research on HUS has been intensified and the pathophysiological mechanism has been continuously improved. At present, the main mechanism of pathogenesis is the excessive activation of complement alternative pathways mediated by complement-related gene mutations or the existence of antibodies. The treatment methods and strategies are also constantly updated, mainly including complement-blocking drugs such as Eculizumab, Lavalizumab, and Ravulizumab. In this review, the new developments in the pathogenesis and treatment of HUS is summarized, and provide references for the clinical treatment of HUS.

Hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli in a renal transplant recipient case report / Síndrome hemolítico-urêmica causada por Escherichia coli produtora de toxina Shiga em um relato de caso de receptor de transplante renal

Abstract Thrombotic microangiopathies are disorders characterized by nonimmune microangiopathic hemolytic anemia, thrombocytopenia, and multi-systemic failure. They are classified as thrombotic thrombocytopenic purpura, atypical hemolytic-uremic syndrome, and typical hemolytic uremic syndrome. The latter is associated with intestinal infections by Shiga toxin-producing bacteria. Typical hemolytic uremic syndrome in adults is an extremely rare condition, characterized by high morbidity and mortality. It has been seldom described in solid organ transplant recipients. Here is presented the case of a kidney transplant recipient who had typical hemolytic uremic syndrome with multisystem commitment, refractory to management and with a fatal outcome.

Resumo Microangiopatias trombóticas são distúrbios caracterizados por anemia hemolítica microangiopática não imune, trombocitopenia e insuficiência multissistêmica. Elas são classificadas como púrpura trombocitopênica trombótica, síndrome hemolítico-urêmica atípica e síndrome urêmica hemolítica típica. Essa última está associada a infecções intestinais por bactérias produtoras da toxina Shiga. A síndrome hemolítica urêmica típica em adultos é uma condição extremamente rara, caracterizada por alta morbimortalidade. Esta é raramente descrita em receptores de transplantes de órgãos sólidos. Apresentamos aqui o caso de um receptor de transplante renal que apresentava síndrome hemolítico-urêmica típica com comprometimento multissistêmico, refratário ao tratamento, e com desfecho fatal.

Síndrome hemolítico urémico asociado a toxina Shiga con hipocomplementemia en edad atípica. Caso clínico

The Shiga toxin associated (Stx) hemolytic uremic syndrome (HUS) is an important cause of acute renal failure (ARF) and the most common cause of thrombotic microangiopathy (TMA) in pediatrics. Primary atypical HUS (aHUS) is a rare disease due to a genetic defect in the alternative complement pathway. Both diseases may share clinical and laboratory elements, making differential diagnosis difficult, such as the presence of diarrhea in aHUS or complement alterations in HUS-Stx. The treatment and prognosis of both diseases is completely different. We report a 15-year-old male with severe HUS. After a self-limited diarrheal syndrome, he had a severe TMA and ARF, requiring renal replacement therapy. An extensive etiological study was carried out, ruling out the main causes of TMA. Alterations in complement factors were observed. Finally, the diagnosis of HUS-Stx was established. The patient evolved favorably with recovery of renal function.

Aislamiento de Escherichia coli productora de toxina Shiga (STEC) en heces de ganado y detección de factores de virulencia asociados con su patogénesis / Isolation of Shiga toxin-producing Escherichia coli (STEC) in cattle stool and detection of virulence factors associated with its pathogenesis

Resumen Objetivo: Aislar STEC en las heces del ganado bovino en el municipio de Ulloa, Valle del Cauca y detectar factores de virulencia asociados con la patogénesis. Materiales y métodos: Se tomaron 21 muestras provenientes de bovinos, las cuales fueron tomadas directamente del recto del animal mediante hisopos. Las muestras se procesaron hasta obtener colonias puras a las cuales se les evaluó la presencia de los genes stx1, stx2, eae, saa y hlyA mediante PCR y posteriormente, se evaluó el efecto citotóxico de las muestras positivas sobre células Vero (ATCC-CCL-81.4). Resultados: De las 21 muestras de heces de bovinos,12 presentaron bacterias con uno o ambos genes stx. Se obtuvieron 106 aislamientos totales de STEC y se observaron diferencias en cuanto a la presencia y ausencia de los genes de virulencia evaluados en los aislamientos de cada bovino, obteniendo cinco combinaciones de genes. 48 aislamientos presentaron únicamente el gen stx2 y 58 presentaron tanto el gen stx1 como el gen stx2; de los 106 aislamientos, se detectaron 44 con el gen hlyA y 57 con el gen saa. Conclusiones: Todos los sobrenadantes de STEC analizados mostraron actividad citotóxica sobre las células Vero, mientras que en ausencia de STEC las células formaron monocapa después de 48 h de incubación. Este trabajo es el primer reporte en Colombia que aporta información sobre la presencia de STEC en el ganado bovino, la presencia de factores de virulencia y el potencial efecto citotóxico que poseen estas cepas nativas.

Abstract Objective: To isolate STEC in stool samples from cattle in Ulloa, Valle del Cauca, and to detect virulence factors associated with its pathogenesis. Materials and methods: We took 21 samples from cattle, which were taken directly from the rectum of the animal using swabs. The samples were processed until obtaining pure colonies and evaluated for the presence of the stx1, stx2, eae, saa and hlyA genes by PCR. Afterward, the cytotoxic effect of positive samples were evaluated on Vero cells (ATCC-CCL- 81.4). Results: We observed that from the 21 stools samples, 12 presented bacteria with one or both stx genes. A total of 106 isolates of STEC were obtained and differences among each other were observed regarding the presence and absence of the virulence genes, obtaining five combinations of genes. We found that 48 isolates presented only stx2 gene and 58 presented both the stx1 and stx2 gene. Regarding the other virulence genes, the hlyA gene was detected in 44 isolates and the saa gene was detected in 57 isolates. Conclusions: All the STEC supernatants showed cytotoxic activity on Vero cells, while in its absence the cells formed monolayer after 48 h of incubation. This work is the first report in Colombia that provides information about the presence of STEC in stool cattle, virulence genes and its potential cytotoxic effect in native strains.

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)

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

ABSTRACT: 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.

RESUMO: 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.

Molecular characteristics of Escherichia coli strains producing Shiga toxin 2e subtype from different sources / 中华微生物学和免疫学杂志

Objective:To understand the molecular characteristics of Escherichia coli producing Shiga toxin 2e subtype isolated from different sources in China. Methods:Three human-derived, 13 animal-derived and eight food-derived stx2e-positive Escherichia coli strains which were isolated during 2012 to 2018 were analyzed by antimicrobial susceptibility testing and whole genome sequencing. The stx subtype, serotype, multi-locus sequence type, virulence genes and antimicrobial resistance genes of each strain were determined by whole genome sequences. The phylogenetic relationship and genetic composition of Shiga-toxin prophage were explored. Results:Twenty-four stx2e-STEC strains were typed into 19 O∶H serotypes and 19 sequence types (STs). Each strain carried at least one kind of antimicrobial resistance gene and 19 out of 24 strains were resistant to at least one kind of antimicrobials. Three human-derived strains were heterogenous in serotypes and STs, but there were several animal and food-derived strains shared the same serotype or ST with human strains and showed close relationship in the phylogenetic analysis. The sequences of stx2e among all strains were highly conserved (similarity >99.7%), but there were significant differences in the size and the gene composition of Shiga toxin prophage genome. Conclusions:This is report about the characteristics of rare human-derived Stx2e-STEC strains in China. Comparing human isolates with animal-and food-derived strains, it indicates that Stx2e-STEC strains are highly genetic diversity and have the potential to infect humans.

Síndrome hemolítico urémico en una mujer adulta mayor: reporte de caso y revisión de la literatura / Hemolytic uremic syndrome in an older adult woman: case report and literature review

El síndrome hemolítico urémico (SHU) típico en adultos es una patología infrecuente. En la literatura se encuentran pocos reportes, y se ha documentado principalmente en la población pediátrica. Esta entidad se caracteriza por ser una microangiopatía trombótica (MAT) que compromete de manera característica los riñones. Es causada usualmente por la infección por Escherichia coli productora de toxina Shiga (STEC), específicamente el serotipo O157:H7. En Colombia no existen casos reportados sobre esta condición en adultos, lo cual llama la atención, pero puede deberse en parte a las dificultades en su diagnóstico, al no tenerse fácil acceso a algunas de las pruebas que orientan hacia esta enfermedad y confirman el diagnóstico. Se reporta el caso de una mujer adulta mayor colombiana, quien consultó por deposiciones diarreicas y hematoquecia, con el posterior desarrollo de trombocitopenia severa, lesión renal aguda, y evidencia de equinocitos y esquistocitos en extendido de sangre periférica, lo que llevó a sospechar una MAT. Se le solicitó FilmArray® gastrointestinal, el cual fue positivo para STEC, confirmando así el diagnóstico de un SHU típico. Se presenta también una breve revisión del tema de una entidad que requiere un diagnóstico temprano y certero que permita brindar un tratamiento eficaz y oportuno

The classic or typical hemolytic uremic syndrome (HUS) in adults is a rare disease. Few reports are found in the literature, and it has mainly been documented in the pediatric population. This condition is a form of thrombotic microangiopathy (TMA), which characteristically compromises the kidneys. It is mainly caused by infection with Shiga toxin-producing Escherichia coli (STEC), specifically the O157:H7 serotype. In Colombia there are no reports on this condition in adults, and may be due in part to difficulties in its diagnosis, as there is not easy access to some of the tests that guide towards this condition and confirm the diagnosis. The case of an elderly Colombian woman is reported, who presented diarrhea and hematochezia, and subsequently developed severe thrombocytopenia and acute kidney injury, with evidence of echinocytes and schistocytes in peripheral blood smears, which led to suspect TMA. A gastrointestinal FilmArray™ was ordered, which was positive for STEC, thus confirming the diagnosis of a typical HUS. A brief literature review is also presented, which covers general concepts of a condition that requires an early and accurate diagnosis in order to provide an effective and timely treatment

Caracterización molecular de aislamientos de Escherichia coli productores de toxina Shiga obtenidos en 2 establecimientos ganaderos del Paraguay Caracterización molecular de aislamientos de STEC de ganado bovino paraguayo / Molecular characterization of Shiga toxin producing Escherichia coli isolated from 2 livestock establishments of Paraguay

Resumen Escherichia coli productora de toxina Shiga (STEC) es un patógeno de importancia alimentaria en los humanos, el bovino es su principal reservorio. El objetivo de este estudio fue determinar la portación de STEC en bovinos del Paraguay y analizar el perfil de virulencia y los serotipos de los aislados reunidos. Se estudiaron 197 muestras de hisopado rectal de bovinos y un promedio de 5 a 50 colonias por bovino positivo a genes stx 1 /stx 2. Se amplificaron por PCR los genes stx 1, stx 2, saa, ehxA y eae. El 84,8% de los bovinos resultaron portadores de STEC. Los perfiles de virulencia predominantes fueron stx 2 y stx 2 /saa/ehxA. La serotipificación se realizó por reacciones de aglutinación en 60 aislamientos seleccionados, se encontró un aislamiento del serogrupo O103, capaz de producir infecciones en humanos. Este trabajo muestra los primeros datos de portación de STEC de ganado bovino paraguayo y señala la necesidad de efectuar otros estudios con mayor cobertura territorial, para lograr una visión completa de este fenómeno.

Abstract Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen in humans, with cattle being the main reservoir. The objective of this study was to determine the carrying of STEC in Paraguayan bovines and to analyze the virulence profile and serotypes of these isolates. A total of 197 samples of bovine fecal samples and an average of 5 to 50 colonies from stx 1 /stx 2 positive samples were studied. The stx 1 , stx 2 , saa, ehxA and eae genes were amplified by PCR. 84.8% of the cattle were carriers of STEC. The predominant virulence profiles were stx 2 and stx 2 /saa/ehxA. The serotyping was performed by agglutination reactions for 60 selected isolates, resulting in isolation of serogroup O103, which could produce infections in humans. This work shows the first data of STEC carriers in Paraguayan cattle, and indicates the need for other studies with greater territorial coverage for a complete vision of this phenomenon.

Infecciones por Escherichia coli productora de toxina Shiga O121: H19 en pacientes atendidos en Mar del Plata / Infections caused by Escherichia coli producing Shiga O121: H19 toxin in patients treated in Mar del Plata

Escherichia coli productora de toxina Shiga (STEC) O157:H7 es el serotipo más frecuentemente identificado como agente causal de colitis hemorrágica y síndrome urémico hemolítico (SUH), aunque se han descripto más de 100 serotipos con potencial patogénico similar. El objetivo del trabajo fue describir casos de enfermedad humana asociados a la infección por STEC O121:H19, atendidos en la ciudad de Mar del Plata y establecer la relación genética de los aislamientos mediante técnicas de epidemiología molecular. Se observó un amplio espectro en la severidad clínica de los ocho casos estudiados: dos fueron asintomáticos (contactos de SUH), un paciente tuvo diarrea sanguinolenta, y cinco presentaron SUH. Uno de los pacientes con SUH falleció. Las cepas O121:H19 portadoras del genotipo stx2a/eae/ehxA fueron sensibles a los antibióticos ensayados y presentaron por electroforesis en gel de campo pulsado (Xbal-PFGE) distintos patrones de macrorrestricción, con similitud del 84,25%. El patrón AREXKX01.0072, detectado en un SUH y en su contacto, es nuevo en la Base de Datos Nacional de STEC no-O157 de la Argentina. La utilización de métodos estandarizados de detección y tipificación de STEC permite a los laboratorios de referencia monitorear la frecuencia temporal y la distribución geográfica de las cepas circulantes para la prevención y control de estos patógenos asociados a enfermedad humana.

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the most frequent serotype identified as causative agent of sporadic cases and outbreaks of diarrhea with or without blood, hemorrhagic colitis and hemolytic uremic syndrome (HUS), although more than 100 serotypes have been described of similar pathogenic potential. The aim of the study was to describe cases of human disease associated with STEC O121:H19 infections, assisted in Mar del Plata City, and to establish the genetic relationship of the isolates by molecular epidemiology techniques. A wide spectrum was observed in the clinical severity of the eight cases studied: two were asymptomatic (contacts of HUS), one patient had bloody diarrhea, and five cases presented HUS. One HUS case died. All STEC O121:H19 strains carried the stx2a/eae/ehxA genotype, were sensitive to all antibiotics tested and showed different macrorestriction patterns by pulsed-field gel electrophoresis (Xbal-PFGE), with 84.25% similarity. The pattern AREXKX01.0072, detected in a HUS case and in his contact, is new in the Argentine National Database of non-O157 STEC. The use of standardized methods for detection and typing of STEC allows reference laboratories to monitor the temporal frequency and geographical distribution of circulating strains for the prevention and control of these pathogens associated with human diseases.

Escherichia coli produtora de toxina Shiga (STEC) O157:H7 é o sorotipo mais frequentemente identificado como o agente causador de colite hemorrágica e síndrome hemolítica urêmica (SHU), embora tenham sido descritas mais de 100 sorotipos com potencial patogênico semelhantes. O objectivo foi o de descrever os casos de doença humana associadas com a infecção por STEC O121:H19, assistido, na cidade de Mar del Plata e estabelecer relação genética de isolados utilizando epidemiologia molecular. Um amplo espectro foi observado na severidade clínica dos oito casos estudados, dois eram assintomáticos (contacto SHU), uma paciente teve diarreia com sangue, e cinco tiveram SHU. Um caso de SHU faleceu. As cepas O121:H19 portaram o genótipo stx2a/eae/ehxA, foram sensíveis aos antibióticos testados e apresentaram, por eletroforese em gel de campo pulsado (Xbal-PFGE), diferentes padrões de macrorestrição, com similaridade de 84,25%. O padrão AREXKX01.0072 detectado em SHU e em seu contato, é novo para a Base de Dados Nacional de STEC não-O157 na Argentina. O uso de métodos padrão de detecção e tipagem de STEC permite os laboratórios de referência monitorar frequência temporal e distribuição geográfica de estirpes circulantes para a prevenção e controlo destes agentes patogénicos associados com a doença humana.

Immunological detection assays for recombinant Shiga toxin & Shigella dysenteriae

Background & objectives: Shiga toxin (Stx) is produced by Shigella dysenteriae, a Gram-negative, facultative anaerobic bacillus that causes shigellosis, haemolytic uraemic syndrome (HUS) and Reiter's syndrome. The detection methods for shiga toxin needs to be rapid, accurate, reliable and must be extensively evaluated under field conditions. The aim of this study was to develop rapid, sensitive and specific detection method for Stx. Methods: Mice and rabbits were immunized with purified recombinant Shiga toxin B (rStxB). Using these antibodies dot ELISA, sandwich ELISA and flow through assay were developed. Results: The high-titre antibodies specifically reacted with purified rStxB. Dot-ELISA, sandwich ELISA and flow-through assay were developed and standardized that could detect StxB with limit of detection (LOD) of 9.75, 9.7 ng/ml and 0.46 ?g/cassette, respectively. Interpretation & conclusions: The rStxB was used to produce antibodies to avoid handling of pathogen. The Flow through assay 'developed was specific, rapid and field amenable.

Primer reporte de escherichia coli productora de toxina shiga no O157 que codifica el gen de la enterohemolisina en carne cruda en colombia / First report of Shiga toxin-producing escherichia coli non-O157 that encodes the enterohemolysin gene in raw beef in colombia

Dentro de los patotipos de Escherichia coli, el grupo STEC puede producir en el ser humano desde diarrea hemorrágica hasta insuficiencia renal aguda e incluso la muerte; el ganado bovino es el principal reservorio de este agente patógeno y por ende la ingestión de alimentos derivados de estos animales de abasto son una fuente muy importante de infección para el hombre. El objetivo principal de este estudio fue determinar la prevalencia de STEC en muestras de carne cruda comercializada en Pamplona-Colombia y en cepas obtenidas a partir de las muestras. Se analizaron cien muestras de carne cruda aplicando la técnica de Reacción en Cadena de la Polimerasa para la detección de los siguientes genes en muestras y en cepas STEC: stx1, stx2, eae y hlyA. Adicionalmente, se estableció el patrón de resistencia-susceptibilidad antibiótica de cepas STEC aisladas empleando métodos regulados. En el 39% de las muestras fue posible detectar el gen stx2; en el 38%, de ellas, se detectaron los genes stx1 y stx2. Además, se aislaron cepas STEC en el 13% de las muestras analizadas, 85% de ellas portaban el gen hlyA. No se detectó la presencia del gen eae o del serogrupo O157. Las cepas aisladas demostraron resistencia frente a algunos antibióticos de primera y segunda generación. En conclusión, se detectó la presencia de genes que codifican factores de virulencia en las muestras de carne analizadas que representan un riesgo potencial para la salud de los consumidores. Este es el primer reporte de STEC no O157 que codifica el gen de la enterohemolisina en alimentos en Colombia(AU)

Within the Escherichia coli patotypes, the STEC group can produce in humans from hemorrhagic diarrhea to acute renal failure and even death; cattle are the main reservoir of this pathogen and therefore the ingestion of food derived from these stock animals are a very important source of infection for man. The main objective of this study was to determine the prevalence of STEC in raw meat samples marketed in Pamplona-Colombia and in strains obtained from those samples. One hundred raw meat samples were analyzed using the Polymerase Chain Reaction technique for the detection of the following genes in samples and in STEC strains: stx1, stx2, eae and hlyA. In addition, STEC strains were isolated in 13% of the analyzed samples, 85% of them carried the hlyA gene. The presence of the eae gene or serogroup O157 was not detected. The isolated strains demonstrated resistance against some first and second generation antibiotics. In conclusion, the presence of genes encoding virulence factors in the meat samples analyzed, that represent a potential health risk factor to consumers, was confirmed. This is the first report of STEC non-O157 that encodes the enterohemolysin gene in foods in Colombia(AU)

Molecular epidemiology of sequence type 33 of Shiga toxin-producing Escherichia coli O91:H14 isolates from human patients and retail meats in Korea

Sequence type (ST) 33 of Shiga toxin-producing Escherichia coli (STEC) strain O91:H14 has been proposed as a potential domestic clone of STEC in Korea because of its high prevalence among human patients with mild diarrhea or asymptomatic carriers. Herein, the clonal diversity of 17 STEC O91:H14 isolates of ST33 during 2003 to 2014 was analyzed by pulsed-field gel electrophoresis, including 14 isolates from human patients and 3 from retail meats. Their virulence characteristics, acid resistance, and antimicrobial susceptibility were also determined. Our results showed that all isolates were clustered mainly into three different pulsotypes and were likely low pathogenic without antimicrobial resistance.

Advance in Shiga toxin / 中华微生物学和免疫学杂志

Shiga toxin (Stx), which can be divided into Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2), is an important virulence factor of Shigella spp. and certain strains of Escherichia coli. Stx, enco-ded by λ-like phage, blocks protein synthesis through removal of an adenine residue from the 28S rRNA. Stx can also induce apoptosis through multiple pathways. Humans may suffer from diarrhea, hemorrhagic colitis ( HC) and hemolytic uremic syndrome ( HUS) and even death when infected with Shiga toxin-producing bac-teria. At present, there is no specific treatment for diseases caused by Stx. In recent years, the application of Stx in cancer therapy and imaging has aroused great interest. This review provided a brief overview of Stx in its nomenclature, typing, structure, genetics, pathogenesis and application perspectives.

Isolated abducens nerve palsy treated by immunoadsorption in a patient with diarrhea-associated hemolytic uremic syndrome / Parálisis ocular aislada del sexto par craneal tratada con inmunoadsorción en un paciente con síndrome urémico hemolítico asociado a diarrea

Shiga toxin-producing Escherichia coli (STEC) that causes a prodromal hemorrhagic enteritis is the main cause of hemolytic uremic syndrome (HUS) particularly in pediatric patients. It is characterized by acute kidney injury with microangiopathic hemolytic anemia and thrombocytopenia. The kidney and brain are the two major target organs, and neurological involvement is the most frequent cause of mortality. The time delay between bloody diarrhea and neurological symptoms ranges from few days to a month. Neurological disorders include disturbances in cognitive functions, focal neurological signs, epileptic seizures, myoclonus and neuropsychiatric symptoms. Cerebral magnetic resonance imaging reveals various patterns of hyperintensities distributed through cerebral matter or may be totally normal even the patient has severe neurological involvement. Electroencephalography usually show generalized or focal slowing of the background activity, spikes or sharp waves despite being normal in around 20% of patients. We present here an adult male patient referred to our center with requirement of hemodialysis due to diarrhea-associated HUS complicated by acute kidney injury. Later during the course of plasma exchange therapy the patient developed an isolated abducens nerve palsy. Complete renal recovery was achieved by plasma exchange therapy but abducens palsy remedied rescue introduction of immunoglobulin G (IgG) depletion by immunoadsorption

Escherichia coli, productor de toxina Shiga (STEC), que causa una enteritis hemorrágica en fase prodrómica, es la principal causa del síndrome urémico hemolítico (SUH), particularmente, en pacientes pediátricos. Se caracteriza por una lesión renal aguda con anemia hemolítica microangiopática y trombocitopenia. El riñón y el cerebro son los dos órganos principales a los que ataca, y la afectación neurológica es la causa más frecuente de mortalidad. El tiempo que transcurre entre la aparición de diarrea sanguinolenta y los síntomas neurológicos varía entre pocos días y un mes. Los trastornos neurológicos incluyen alteraciones en las funciones cognitivas, signos neurológicos focales, ataques epilépticos, mioclonías y síntomas neuropsiquiátricos. La resonancia magnética de cerebro revela varios patrones de hiperintensidades distribuidas a través de la materia cerebral o puede ser totalmente normal incluso si el paciente tiene un compromiso neurológico severo. El electroencefalograma generalmente muestra una disminución generalizada o focal de la actividad de fondo, picos u ondas agudas, a pesar de ser normal en alrededor del 20% de los pacientes. Presentamos un paciente adulto de sexo masculino, derivado a nuestro centro para ser tratado con hemodiálisis debido a SUH asociado a diarrea, complicado por insuficiencia renal aguda. Luego, durante el transcurso de la terapia de intercambio de plasma, el paciente desarrolló una parálisis ocular aislada del sexto par craneal. Se logró una recuperación renal completa por medio de la terapia de intercambio plasmático; no obstante, la parálisis del nervio motor ocular externo remedió la disminución de la inmunoglobulina G (IgG) mediante el tratamiento de rescate de inmunoadsorción

Development and evaluation of loop-mediated isothermal amplification assay for the rapid detection of Escherichia coli and its microbial toxin / 中国医师杂志

Objective To establish and optimize a loop-mediated isothermal amplification (LAMP) method for the rapid detection of Escherichia coli and its microbial toxin.Methods The LAMP reaction system and reaction conditions were determined by optimizing LAMP reaction,and the optimized LAMP system was used for the detection.Results Primers targeting shiga toxin (stx) gene and O157 antigen gene rfbe were designed.The established and optimized LAMP amplification system contained 1.2 mmol/L dNTPs,10 mmol/L MgSO4,0.4 mol/L betaine,1 μl 10 × Bst DNA polymerase Buffer,8 U Bst DNA polymerase fragment,2 μl DNA template,and the ratio of inner-primer (FIP and BIP) and outerprimer (F3 and B3) were 8∶ 1.Time and temperature for LAMP was 60 min,60 ℃.The sensitivity was 103 times higher than polymerase chain reaction (PCR),reached 5 × 101 CFU/ml.When LAMP was applied to 19 reference strains,102 EHEC strains,the specification was 100％ while identification rate of rfbe,stx1 and stx2 gene reached 100％,95.2％,92.9％.Conclusions The LAMP method showed a promising prospect for the rapid detection of common nosocomial pathogens microbial toxin.

Molecular characteristics of human-derived non-O157 Shiga toxin-producing Escherichia coli strains isolated in five regions of China / 中华微生物学和免疫学杂志

Objective To understand the molecular characteristics of human-derived non-O157 Shiga toxin-producing Escherichia coil (STEC) strains circulating in five regions of China.Methods Twenty-seven non-O157 STEC strains isolated in five geographic regions were investigated by serotyping, stx1/stx2 subtyping and PCR screening for adhesion and other virulence genes.A multilocus sequence typing (MLST) scheme provided by E.coil MLST database were performed to amplify and sequence seven housekeeping genes (adk, icd, fumC, rgyrB, purA, mdh and recA) in those strains.Results Twenty-seven non-O157 STEC strains were typed into 16 O∶H serotypes.Among those strains, 11 harbored stx1a, 12 harbored stx1c, two harbored stx2e and the other three strains respectively harbored stx1a+stx2b, stx2d and stx2g.Positive rates of eae, efa1, saa, paa, toxB, astA and ehxA genes were 18.5%, 18.5%, 29.6%, 22.2%, 11.1%, 11.1% and 25.9%, respectively.The 27 strains were typed into 16 different sequence types (STs) based upon MLST.Conclusion Human-derived non-O157 STEC strains circulating in five regions of China are heterogeneous in their serotypes, stx1/stx2 subtypes and virulence gene profiles.

Serotype identification and antibiotic susceptibility of Shiga toxin-producing Escherichia coli in the Weishan area in Shandong Province, China / 中华预防医学杂志

Objective@#To determine the serotypes and drug resistance profiles of Shiga toxin-producing Escherichia coli (STEC) in animal stools from the Weishan area in Shandong Province, China. To provide the basis for further study.@*Methods@#Five hundred animal stool samples (from pigs, cattle, sheep, dogs and birds) were collected from the Weishan area and STEC strains were isolated from these samples. Strains were serotyped by a serum agglutination test, and their drug resistance profiles were determined through antimicrobial sensitivity experiments. In this study, PCR was used to detect tetracycline resistance genes (tetA, tetB, tetC, tetD) and beta-lactam resistance genes (blaSHV-1, blaCTX-M, blaTEM).@*Results@#Sixteen strains of STEC were isolated from animal stool samples. Thirteen strains were isolated from pig stool samples, two from bovine stool samples and one from a sheep stool sample. Two of the strains were identified as E. coli O157:H7, and other 14 strains were non-O157 STEC of different serotypes. Antimicrobial sensitivity experiments showed that 15 of the strains were multidrug resistant. The rates of resistance were as follows: nalidixic acid (12/16 strains), sulfisoxazole (11/16), trimethoprim and sulphame-thoxazole (11/16), doxycycline (9/16), azithromycin (9/16), tetracycline (9/16), chloramphenicol (8/16) and streptomycin (8/16). Therefore, nalidixic acid showed the highest rate of resistance among the strains, followed by trimethoprim and sulphame-thoxazole, and sulfisoxazole. Resistance to cefepime or imipenem was not detected. In total, three types of drug resistance genes (tetA, tetB and tetC) were detected among the 16 strains.@*Conclusion@#The results showed that STEC strains isolated from animals in the Weishan area were of a range of serotypes. The 16 strains of STEC isolated from animal stools in this area were resistant to a number of antibiotics, with many strains displaying multidrug resistance.

Flooding adds pathogenic Escherichia coli strains to the water sources in southern Khyber Pakhtunkhwa, Pakistan.

Purpose: Seasonal rains in Pakistan result in heavy floods across the country, whereby faecal contaminants will be added to the water bodies and cause numerous food‑borne outbreaks. The present study was aimed to determine the prevalence of diarrheagenic Escherichia coli (DEC) strains in the water sources. Materials and Methods: Two hundred water samples collected during (2011–2012) were processed for the isolation of E. coli (EC) strains. EC strains were further analysed for antibiotic susceptibility patterns, and pathogroups‑specific virulence factors stx1, stx2, stx2c, eae, tir, hlyA, bfpA, estA and eltA were detected using multiplex polymerase chain reaction. Results: Thirty‑three percent of the water samples were contaminated with EC pathotypes. Fifty percent (33/66) of the DEC pathotypes were identified as enterotoxigenic EC (ETEC). Seventy‑two percent (13/18) of the enteropathogenic EC (EPEC) strains were identified as typical EPEC and 28% (5/18) as atypical EPEC. Eleven percent (7/66) of the Shiga toxin EC (STEC) isolates carried a combination of stx1 and stx2 genes. Summer was found as a peak season with 47% (31/66) for EC pathogroups’ activities. Eighty‑nine percent of the strains showed resistance against tetracycline. Conclusion: ETEC and EPEC are the primary causes of water contamination in southern regions of Khyber Pakhtunkhwa province, Pakistan. Firm adherence to the prescribed drugs can decrease trends in antibiotic resistance.