[Prevalence of Shiga toxin-producing genes in Escherichia coli isolated from patients with urinary tract infections in Khorramabad]

Background and Objectives: Shiga toxins [verotoxin] is one of the most important bacterial toxin produced by the Escherichia coli [O157: H7 and nonO157: H7], and is responsible for various diseases in humans and animals. Hemolytic uremic syndrome [HUS] is serious human diseases that occur because of these toxins. There is no comprehensive information in this regard, here will studied the prevalence of these genes among the E- coli isolated from urine samples in Khorramabad

Material and Method: The study is based on 146 Escherichia coli isolates of Patients with symptoms of urinary tract infection referred to clinical laboratories in Khorramabad during 90-1389. We used we identified the isolates by biochemical tests .The Multiplex PCR Multiplex PCR method were used to presence of genes

Results: A total of 117 [13/80%] of the women and 29 [86/19] of the men and none of them carried both stx1and stx2

Conclusion: Shiga toxin-producing E. coli isn't responsible for urinary tract infection in KhorramabadAlthough the frequency of these genes in urine samples is low, but evaluation of the other human and animal samples in different parts of the country is essential

Caracterização molecular de amostras de Escherichia coli carreadoras dos genes stx isoladas de bovinos nos estados de Rondônia e do Rio de Janeiro / Molecular characterization of Escherichia coli carrier of stx genes isolated from cattle in the states of Rondônia and Rio de Janeiro

Escherichia coli produtora da toxina Shiga (STEC) é agente de diarreia esporádica e de epidemias, podendo ocasionar quadros clínicos graves em seres humanos. A habilidade de STEC em causar doenças severas em seres humanos está relacionada com a sua capacidade de secretar as toxinas Stx1, Stx2 e/ou variantes toxigênicas. Outro fator de virulência de STEC é a intimina, codificada pelo gene eae e associada com aderência íntima, inicialização das vias de transdução de sinais e formação da lesão intestinal íntima. Algumas STEC também produzem enterohemolisina, codificada pelo gene ehxA, que tem sido associada com doença severa em seres humanos. Bovinos constituem seu principal reservatório assumindo papel relevante na infecção dos seres humanos. Características de manejo do animal sugerem conferir fatores de risco para a excreção desses patógenos. O objetivo desse estudo foi investigar a prevalência e as características biogenéticas de Escherichia coli carreadora dos genes stx (STEC), isoladas de amostras fecais de bovinos, com e sem diarréia, de regiões agropecuárias localizadas nos estados do Rio de Janeiro e Rondônia. Para atingir a presente proposta, 301 isolados de E. coli provenientes de ambas as regiões, foram submetidos a análises moleculares baseadas em ensaios de amplificação visando o diagnóstico de E. coli carreadora do gene stx, seu potencial de patogenicidade e diversidade genética. (...)

A análise do genoma total empregando ensaios de amplificação randômica do DNA polimórfico revelou uma elevada diversidade genética entre as amostras de E. coli carreadoras do gene stx sugerindo constituir uma população bacteriana de origem não-clonal. Nossos resultados nos levam a concluir que a maior prevalência de STEC em Rondônia, possivelmente reflete as condições mais precárias de suas propriedades rurais. O isolamento de STEC de bovinos clinicamente sadios reforça o reconhecido papel desses animais como reservatórios assintomáticos. Nossos resultados contribuíram para o esclarecimento sobre a epidemiologia das STEC em especial, no estado de Rondônia, onde as informações sobre a circulação deste patógeno ainda são limitadas. Esses achados salientam a necessidade de manter uma vigilância epidemiológica ativa, em especial no que diz respeito a estudos sobre reservatórios e atributos de virulência bacteriana.

Caracterização de Escherichia coli produtoras de toxina de Shiga (STEC) isoladas na produção de bovinos de corte e nas respectivas carcaças dos animais abatidos / Characterization of Shiga toxin-producing Escherichia coli (STEC) isolated in feedlot beef cattle production and their carcasses

Escherichia coli produtoras de toxina de Shiga (STEC) são considerados importantes patógenos de origem alimentar que apresentam o trato intestinal de ruminantes domésticos, principalmente bovinos, seu reservatório natural. Esses microrganismos estão associados com doenças severas em humanos, tais como colite hemorrágica (CH) e síndrome urêmica hemolítica (SHU). Este trabalho teve como objetivos avaliar a ocorrência de STEC em diferentes fontes, ambientais ou não, da criação e abate de bovinos confinados. Além disso, detectar a presença dos genes stx1, stx2, ehxA e eaeA; identificar cepas O157:H7 através da pesquisa do gene uidA; evidenciar a capacidade de produção de Stx e de Eh; identificar variantes de stx e de eaeA; e determinar os sorotipos a diversidade genética das cepas de STEC. A avaliação da presença dos genes (stx1, stx2, ehxA e eaeA) e da produção de Eh foi utilizada como triagem para a seleção de cepas possivelmente patogênicas, sendo que do total de 628 isolados avaliados, foram selecionadas 47 cepas STEC típicas e outras 12 consideradas como atípicas. Das STEC típicas 80,9% foram isolados provenientes de amostras de fezes, enquanto 19,1% foram de amostras de carcaças. Seis cepas isoladas de fezes e 1 de carcaça foram sorotipificadas como 0157:H7, todas positivas para a presença do gene uidA. Além do sorogrupo 0157, nenhum outro, dentre os principais causadores de surtos e casos esporádicos de CH e SHU, foi detectado...

[Detection of E.coli strains containing shiga toxin [stx1/2] gene in diarrheal specimens from children less than 5 years old by PCR technique and study of the patterns of antibiotic resistance]

Shiga toxin- producing Escherichia coli [STEC] is an emerging bacterial pathogen in developing countries that causes several diseases such as diarrhea, hemorrhagic colitis [HC] and hemolytic uremic syndrome [HUS], particularly in children. Aim of the research was detection of STEC in diarrheal specimens from under 5 year olds and study of the patterns of antibiotic resistance of these strains. In the study, 300 fecal samples were collected from children with diarrhea referring to Ali Asghar Hospital. E.coli species were isolated by standard bacteriological and biochemical tests. Presence of shiga toxin genes [stx 1/2] was investigated by PCR technique [Qiagen]. Antibiogram test for strains containing the toxin gene was performed using 16 different antibiotic discs [MAST] by disc diffusion agar [Kirby- Bauer] method. From 39 E.coli isolates, 9[23.1%] strains were detected by PCR to contain stx 1/2 gene. One strain was resistant to all 16 antibiotics. All the STEC strains were sensitive to meropenem [MRP], imipenem [IMI], gentamycin [GEN] and nitrofurantoin [NI]. 4[44.44%] strains showed multi-drug resistant pattern. All these 4 strains were resistant to cotrimoxazole [SxT]. Also, 6[66.66%] strains were resistant to at least one antibiotic. In Iran, shiga toxin-producing Escherichia coli [STEC] may be a commonly bacterial pathogen causing diarrhea, particularly in children. Therefore, we should use new techniques for investigation of these strains. Increase in number of emerging and new strains that could be resistant to classic antibiotics such as cortimoxazole may be foreseen. It is suggested that antibiotics prescription programs in treatment of diarrhea causing E.coli strains be updated

Molecular characterization of shiga like toxin-producing Escherichia coli (STEC) isolates from pigs oedema.

BACKGROUND & OBJECTIVE: An oedema outbreak occurred in a Guwahati pig farm. Escherichia coli isolates from different necropsy samples collected from the dead piglets with oedema were characterized to confirm the virulence. METHODS: Haemolytic E. coli isolates recovered from liver, lung and intestine of pigs with oedema were examined for presence of genes encoding pathogroups such as enteropathogenic Escherichia coli (EPEC), (eae/bfpA), enteroaggregative Escherichia coli (EAggEC), (eagg), enterotoxigive Escherichia coil (ETEC), (elt/est) and shiga like toxin producing Escherichia coli (STEC), (stx1/ stx2) by PCR and molecular typing by randomly amplified polymorphic DNA-PCR (RAPD-PCR). RESULTS: The three haemolytic E. coli recovered from diseased pigs were STEC because of presence of the stx2 and eae genes. Analysis by RAPD-PCR indicated that two of the three isolates were genetically related. INTERPRETATION & CONCLUSION: The isolation of STEC isolates from pigs with oedema was shown. Although the three isolates were untypable, presence of eae and stx2 genes clearly indicated these as prime cause of pig oedema disease. Further, demonstration of STEC in pigs becomes a public health concern, as pigs are potential reservoir of such agents, which may cause human illness.

Análisis in silico de la capacidad de dos técnicas de PCR para la detección del gen stx / In silico analysis of the capability of two polimerase chain reaction techniques for stx gene detection.

Escherichia coli productor de toxina Shiga es un patógeno emergente cuyo principal factor de virulencia son las toxinas Shiga (Stx), codificadas por los genes stx. Estas toxinas se clasifican en 6 tipos (1, 2, 2c, 2d, 2e y 2f) que agrupan a 22 variantes. En Argentina se validaron dos técnicas de PCR para la detección de los genes stx, PCR-MK y PCR múltiple. Los objetivos del trabajo fueron analizar mediante el uso de herramientas bioinformáticas la capacidad de dichas técnicas para detectar las variantes del gen stx y demostrar experimentalmente la amplificación de 8 variantes stx. Se recopilaron 25 secuencias nucleotídicas de la base de datos GenBank correspondientes a 21 variantes de stx. Se utilizó el programa BLAST 2 sequences para analizar la complementariedad de las bases nucleotídicas entre las secuencias de las variantes y las secuencias de los cebadores utilizados en las PCR estudiadas. La técnica de PCR-MK permite detectar los tipos stx1, stx2, stx2c, stx2d y stx2f, aunque no permite detectar el tipo stx2e y tres variantes del tipo stx2c. La PCR múltiple permite detectar los tipos stx1, stx2, stx2c, stx2d, pero no los tipos stx2e y stx2f. Se demostró experimentalmente que ambas técnicas de PCR son apropiadas para la detección de las variantes que están asociadas a enfermedad grave en el hombre.

Shiga toxin-producing Escherichia coli is an emergent pathogen, being the Shiga toxin (Stx) the main virulence factor. These toxins are classified into 6 types (1, 2, 2c, 2d, 2e and 2f) and 22 variants. In Argentina, two PCR for stx gene detection, PCR-MK and multiplex-PCR, were validated. The aim of this work was to analyze, by using bioinformatic tools, the stx variants that could be amplified by these PCRs, and to experimentally show the amplification of 8 stx variants. Twentyfive nucleotide sequences were collected from GenBank corresponding to 21 stx variants. The BLAST 2 sequences program was used to analyze the complementarities between the nucleotide sequence of the variants and the primers corresponding to the PCR studied. PCR-MK could detect types stx1, stx2, stx2c, stx2d and stx2f, but not type stx2e and three type stx2c variants. On the other hand, the multiplex-PCR could detect types stx1, stx2, stx2c, stx2d, but not stx2e and stx2f types. It was experimentally determined that both PCRs can detect those variants that cause severe disease in humans.

Verotoxic Escherichia coli (STEC) from beef and its products.

In the present investigation, out of 27 (24.10%) strains of Escherichia coli isolated from 112 beef samples comprising raw meat (45), kabab (36) and kofta (31), 9 (33.33%) belonging to 7 different serotypes were verotoxic as tested by vero cell cytotoxic assay. Serotype O145 was the predominant STEC in raw meat. Interestingly, one STEC-O157 strain was also detected. All the STEC strains were positive for Stx genes by polymerase chain reaction showing stx2 (77.78%) to be most predominant followed by stx1 (22.22%). Phenotypic enterohaemolysin production on washed sheep blood agar supplemented with CaCl2 revealed 6 (66.67%) STEC strains to be positive. Presence of STEC in cooked beef products, viz., kabab and kofta appeared to be a matter of concern and potential threat to public health.

Determinación de factores de virulencia asociados a Escherichia Coli Enterohemorrágica en cepas peruanas aisladas entre 1999-2001 / Determination of virulence factors related to Escherichia Coli enterohemorragic Peruvian strain isolated between 1999-2001

En el presente estudio se intentó detectar la presencia del gen de toxina en cepas locales de Escherichia Coli serológicamente relacionados a la catergoria enterohemorrágica, caracterizando además un aislamiento reportado como serotipo 0157:H7 procedente de la ciudad de Tacna (cepa Tacna 410), mediante la reacción en cadena de la polimerasa (PCR) y secuenciamiento. Los resultados confirmaron la presencia del gen de la toxina shiga sólo en la cepa Tacna 410, obteniéndose una identidad del 100 por ciento entre la secuencia nucleótida del gen de la copa Tacna 410 y secuencias reportadas de la toxna shiga de tipo II en el Genebank. Asimismo, se detectó en la cepa Tacna 410 propiedades hemolíticas y el gen eae asociado al fenómeno de attaching and effacing, características de una típica cepa de ECEH.

We tried to detect the Shiga gene in local Escherichia Coli strains serologically related the enterohemorragic category. At the same time, using polymerase chain reaction (PCR) and sequencing, we characterized a strain confirmed as E. Coli 0157:H7 serotype, which was isolated in Tacna (a city in southern Peru) (Tacna 410 strain). Our results confirmed the presence of the Shiga toxin gene only in E. coli strain Tacna 410, and we found 100 percentage identify between the sequence from the amplified gene and reference sequence for type II Shiga toxin in the gene bank. We also detected in the Tacna 410 strain hemolytic properties and the eae gene, which is associated to attaching and effacing lesions, typical features of EHEC, strains.