RESUMO
En mayo de 2002 se aisló por primera vez en Uruguay Escherichia coli O157:H7, productora de toxina shiga a partir del coproductivo de una niña de 16 meses procedente de Melo, con diagnóstico de síndrome urémico hemolítico. La cepa, productora de toxinas shiga tipo 2 y tipo 2 variante humana a, era genéticamente distinta de las cepas circulantes en Argentina.
Assuntos
Humanos , Feminino , Criança , Escherichia coli O157 , Escherichia coli , Infecções por Escherichia coli , Síndrome Hemolítico-UrêmicaRESUMO
En mayo de 2002 se aisló por primera vez en Uruguay Escherichia coli O157:H7, productora de toxina shiga a partir del coproductivo de una niña de 16 meses procedente de Melo, con diagnóstico de síndrome urémico hemolítico. La cepa, productora de toxinas shiga tipo 2 y tipo 2 variante humana a, era genéticamente distinta de las cepas circulantes en Argentina. (AU)
Assuntos
Humanos , Feminino , Criança , Síndrome Hemolítico-Urêmica , Infecções por Escherichia coli/complicações , Escherichia coli/isolamento & purificação , Escherichia coli O157/isolamento & purificaçãoRESUMO
Four hundred and twenty-two calves were examined for intestinal carriage of Shiga toxin-producing Escherichia coli O157:H7 using conventional plating. Two (0.5%) E. coli O157 were recovered. They were compared with 96 Argentine strains of different origin by pulsed-field gel electrophoresis, phage typing and PCR-RFLP of stx2 genes. One strain isolated from a calf, was closely related with 18 strains of clinical origin.
Assuntos
Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli O157/isolamento & purificação , Toxinas Shiga/biossíntese , Animais , Argentina/epidemiologia , Tipagem de Bacteriófagos/veterinária , Bovinos , Doenças dos Bovinos/epidemiologia , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado/veterinária , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Fezes/microbiologia , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Fragmento de Restrição , PrevalênciaRESUMO
Different experimental approaches were evaluated for their ability to detect stx genes by PCR and identify Shiga toxin-producing Escherichia coli (STEC) in bovine fecal samples. One hundred and sixty fecal samples from steers in Argentina were processed by protocols that involved: (1) enrichment of fecal samples and DNA extraction using a commercially available kit (Protocol A); (2) plating on selective media after enrichment of the fecal sample followed by heat-lysis DNA extraction from the confluent growth zone (Protocol B); (3) analysis of individual colonies isolated from direct fecal culture on MacConkey agar and sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (Protocol C), used as Gold Standard. PCR performed on bacteria from the confluent growth zone (Protocol B) proved to be the most sensitive methodology. In addition, enrichment for greater than 6h, enhanced sensitivity. Among eight STEC isolates, four were O8:H19 and four were stx2/eae-negative. An STEC isolate was characterized as O26:H11 with a stx1/eae/EHEC-hlyA genotype, often associated with human disease. Finally, no STEC O157 strains were isolated using these methods.
Assuntos
Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli/metabolismo , Reação em Cadeia da Polimerase/veterinária , Toxina Shiga I/biossíntese , Toxina Shiga II/biossíntese , Animais , Argentina , Bovinos , DNA Bacteriano/química , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/microbiologia , Fezes/microbiologia , Masculino , Antígenos O/sangue , Reação em Cadeia da Polimerase/métodos , Sensibilidade e Especificidade , Toxina Shiga I/genética , Toxina Shiga II/genética , VirulênciaRESUMO
Between February and May 2000, 279 meat samples were collected from 136 retail stores in Gualeguaychú City, Argentina. Samples were assayed for Escherichia coli O157:H7 by selective enrichment in modified EC broth containing novobiocin, followed by immunomagnetic separation (IMS) and plating onto both sorbitol MacConkey agar supplemented with cefixime and potassium tellurite and a chromogenic medium. Eleven E. coli O157:H7 isolates were detected in 6 (3.8%) of 160 ground beef samples, in 4 (4.8%) of 83 fresh sausages, and in 1 (3.3%) of 30 dry sausages. E. coli O157:H7 was not isolated from five hamburger patties or one barbecue-type fresh sausage assayed. The isolates were tested for virulence-related genes. Ten additional Shiga toxin-producing E. coli (STEC) O157:H7 isolates of food origin, recovered from different locations in Argentina, were included for comparison purposes. All 21 isolates harbored both eae and EHEC-hlyA genes, and 12 (57.1%) encoded stx2/stx2vh-a. The isolates were of phage types 87 (seven strains), 14 (four strains), 4 (three strains), and 26 (one strain). Six strains were nontypable by phage typing. Pulsed-field gel electrophoresis (PFGE) revealed 19 XbaI-PFGE profiles. Fifteen (71%) strains were grouped in four clusters, which shared more than 80% of DNA restriction fragments. The enrichment culture method with IMS was a sensitive procedure to detect E. coli O157:H7 strains in retail meats. Some of the isolates from different stores presented a high clonal relatedness, as determined by XhaI-PFGE and phage typing, and harbored the virulence factors associated with human illness.
Assuntos
Escherichia coli O157/isolamento & purificação , Carne/microbiologia , Argentina , Tipagem de Bacteriófagos/métodos , Eletroforese em Gel de Campo Pulsado , Escherichia coli O157/classificação , Escherichia coli O157/genética , Separação Imunomagnética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Toxinas Shiga/genética , VirulênciaRESUMO
We report a case of a nine-year old boy with vomiting, abdominal pain and fever, who underwent surgery with a diagnosis of appendicitis in Mendoza and from whom a Shiga toxin-producing Escherichia coli (STEC) O127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Laboratory findings included: hematocrit, 35%; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildly hydrated child, without fever but with distended and painful abdomen. The patient was again submitted to surgery with a diagnosis of intestinal occlusion. Bleeding and multiple adhesions in jejunum and ileum were found. The patient still had tense and painful abdomen and presented two bowel movements with blood; hematocrit fell to 29% and blood urea nitrogen rose to 0.32 g/L. STEC O127:H21 eae(-)/Stx2/Stx2vh-b(+)/E-Hly(+) was isolated from a stool sample. He was discharged after 10 days of hospitalization and no long-term complications such as HUS or TTP were observed. This is the first report, to our knowledge, on the isolation of E. coli O127:H21, carrying the virulence factors that characterize STEC strains, associated to an enterohemorrhagic colitis case. This serotype was previously characterized as a non-classic enteropathogenic E. coli (EPEC). STEC infections can mimic infectious or noninfectious pathologies. Therefore an important aspect of clinical management is making the diagnosis using different criteria thereby avoiding misdiagnoses which have occasionally led to invasive diagnostic and therapeutic procedures or the inappropriate use of antibiotics.
Assuntos
Toxinas Bacterianas/biossíntese , Infecções por Escherichia coli/complicações , Escherichia coli , Hemorragia Gastrointestinal/microbiologia , Obstrução Intestinal/microbiologia , Abdome/microbiologia , Criança , Enterocolite/microbiologia , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Infecções por Escherichia coli/diagnóstico , Humanos , Masculino , Toxinas ShigaRESUMO
Shiga toxin-producing Escherichia coli (STEC) colonize the lower segments of the human gastrointestinal tract, causing gastrointestinal and systemic diseases. In this study, the effects of Shiga toxin 2 (Stx2) on fluid absorption and ion transport in the human colon were examined. Net water movement (Jw) and short-circuit current (Isc) were simultaneously measured across the colonic mucosa incubated with crude or purified Stx2. Stx2 significantly inhibited the absorptive J(w) with no effect on the basal I(sc) after 60 min of exposure. These effects may be due to the inhibition of a nonelectrogenic transport system present in the surface colonic villus cells. Morphological studies of the colonic mucosa treated with crude or purified Stx2 demonstrated a selective damage in the absorptive villus epithelial cells. These findings suggest that Stx2 inhibits water absorption across the human colon by acting on a specific cell population: the mature, differentiated absorptive villus epithelium.
Assuntos
Toxinas Bacterianas/farmacologia , Colo/efeitos dos fármacos , Colo/metabolismo , Enterotoxinas/farmacologia , Escherichia coli , Transporte de Íons/efeitos dos fármacos , Água/metabolismo , Colo/patologia , Humanos , Técnicas In Vitro , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Toxinas ShigaRESUMO
We report a case of a nine-year old boy with vomiting, abdominal pain and fever, who underwent surgery with a diagnosis of appendicitis in Mendoza and from whom a Shiga toxin-producing Escherichia coli (STEC) O127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Laboratory findings included: hematocrit, 35
; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildly hydrated child, without fever but with distended and painful abdomen. The patient was again submitted to surgery with a diagnosis of intestinal occlusion. Bleeding and multiple adhesions in jejunum and ileum were found. The patient still had tense and painful abdomen and presented two bowel movements with blood; hematocrit fell to 29
and blood urea nitrogen rose to 0.32 g/L. STEC O127:H21 eae(-)/Stx2/Stx2vh-b(+)/E-Hly(+) was isolated from a stool sample. He was discharged after 10 days of hospitalization and no long-term complications such as HUS or TTP were observed. This is the first report, to our knowledge, on the isolation of E. coli O127:H21, carrying the virulence factors that characterize STEC strains, associated to an enterohemorrhagic colitis case. This serotype was previously characterized as a non-classic enteropathogenic E. coli (EPEC). STEC infections can mimic infectious or noninfectious pathologies. Therefore an important aspect of clinical management is making the diagnosis using different criteria thereby avoiding misdiagnoses which have occasionally led to invasive diagnostic and therapeutic procedures or the inappropriate use of antibiotics.
RESUMO
Shiga toxin-producing Escherichia coli (STEC) has been associated with pathogenesis of hemolytic uremic syndrome (HUS) worldwide. The aim of the present study was to characterize the HUS cases reported in Mendoza and to determine their association with STEC infection. From July 1994 through June 1996 thirty-six patients with HUS were admitted to Hospital Pediátrico "Dr. HJ Notti" (Mean age 22.8 +/- 14.9 months, 44% females). The children developed HUS following an acute diarrheal illness in 94.4% of the cases. Bloody diarrhea was observed in 83.3% of them. Antimicrobial therapy had been administered to 69.4% of the patients. Most of the patients were well-nourished (88.9%), belong to middle-low socioeconomical condition (91.7%), from urban areas (72.2%) and they were mostly assisted during summer and the beginning of autumn. The acute stage of the disease occurred with presentation of pallor (100%), edema (25%), anuria (38.9%), oliguria (41.7%), hemolytic anemia (97.2%), thrombocytopenia (86.1%) and neurological involvement (41.7%). Twenty-five of them presented the full clinical syndrome. Peritoneal dialysis were performed in 50% and packed blood cell transfusion in 88.9%. The mean days of hospitalization was 15.1 +/- 9.2 [range 1-32]. A 91.7% of the patients recovered renal function, two developed chronic renal failure and one died. Cumulative evidence of STEC infection was found in 19 (86.4%) of 22 HUS patients. STEC O157:H7, biotype C was found in 8 (36.4%). The prevalent Stx type was Stx2 in STEC, free fecal Stx (STMF) and Stx-neutralizing antibodies (a-Stx). In Mendoza, as in the rest of Argentina E. coli O157:H7, biotype C, Stx2 producer is the most frequently detected pathogen in HUS cases.
Assuntos
Toxinas Bacterianas , Infecções por Escherichia coli/complicações , Escherichia coli , Síndrome Hemolítico-Urêmica/microbiologia , Argentina , Criança , Pré-Escolar , Feminino , Síndrome Hemolítico-Urêmica/tratamento farmacológico , Síndrome Hemolítico-Urêmica/epidemiologia , Humanos , Lactente , Masculino , Estado Nutricional , Fatores SocioeconômicosRESUMO
El objetivo de este trabajo fue estudiar la cinetica de produccion de los distintos tipos de toxinas Shiga (Stx1; Stx2c) asociadas a Escherichia coli, en cepas de referencia y aisladas de pacientes con Sindrome Uremico Hemolitico (SUH). Las cepas fueron cultivadas en caldo Penassay e incubadas a 37§ con agitacion (200 rpm), tomandose muestras a distintos tiempos (1,5; 3; 9 y 24 horas) para determinar el crecimiento bacteriano y la citotoxicidad libre y asociada a celulas. Para Stx1, a las 3 horas de incubacion, la relacion entre la concentracion intracelular y la extracelular (ic/ec), estuvo comprendida entre 32 y 200 veces. A las 24 horas, ambas concentraciones se igualaron o (ec) resulto 2 veces mayor, dependiendo de la cepa estudiada. Sin embargo, tanto la actividad citotoxica libre como la asociada a celulas presentaron titulos muy bajos. Esto indico una perdida de actividad durante la fase estacionaria que podria deberse al cese de la sintesis de Stx1 o la accion de enzimas proteoliticas. Para Stx2, a las 3 horas (ic) fue igual o 2 veces superior a (ec), a las 34 horas (ec) fue 16 a 32 veces superior a (ic). Para Stx2c, (ec) aumento logaritmicamente con un rendimiento maximo a las 5 horas, permaneciendo luego constante hasta las 24 horas. En ese tiempo (ic) fue dos veces superior a (ec). El estudio de la cinetica de produccion de Stx por cepas de E. coli aisladas de pacientes con SUH demostro que correspondian al tipo Stx2. Estos resultados fueron confirmados por ensayos de citotoxicidad especifica en celulas Vero y por hibridacion con sondas geneticas. El tipo de Stx es considerado uno de los mayores factores de riesgo en la evolucion a SUH en pacientes infectados con E. coli enterohemorragicos. Por lo tanto, la disminucion de la citotoxicidad de Stx1, durante la fase estacionaria de crecimiento, podria explicar la mayor frecuencia de accion entre SUH y cepas de E. coli productoras de Stx2 en distintos paises, incluyendo Argentina
Assuntos
Citotoxicidade Imunológica , Citotoxinas/biossíntese , Enterotoxinas/biossíntese , Escherichia coli , Cinética , Síndrome Hemolítico-Urêmica/imunologiaRESUMO
El objetivo de este trabajo fue estudiar la cinetica de produccion de los distintos tipos de toxinas Shiga (Stx1; Stx2c) asociadas a Escherichia coli, en cepas de referencia y aisladas de pacientes con Sindrome Uremico Hemolitico (SUH). Las cepas fueron cultivadas en caldo Penassay e incubadas a 37º con agitacion (200 rpm), tomandose muestras a distintos tiempos (1,5; 3; 9 y 24 horas) para determinar el crecimiento bacteriano y la citotoxicidad libre y asociada a celulas. Para Stx1, a las 3 horas de incubacion, la relacion entre la concentracion int
Assuntos
Citotoxinas/biossíntese , Escherichia coli , Cinética , Síndrome Hemolítico-Urêmica/imunologia , Enterotoxinas/biossíntese , Citotoxicidade ImunológicaRESUMO
We studied the differential kinetic patterns for Shiga toxin (Stx) production (i.e. Stx1, Stx2 and Stx2c) in different reference Escherichia coli strains and in those isolated from hemolytic uremic syndrome (HUS) patients. These results were correlated with those obtained by specific cytotoxic activity assays on Vero cells and hybridization tests with DNA probes for Stx1 and Stx2. Strains cultured in Penassay broth were sampled at 1.5; 3; 5; 9 and 24 hours to determine bacterial growth and its association with cell-bound and free cytotoxicity. Stx1 showed an intracellular/extracellular concentration ratio (ic/ec) between 32 and 200 times after 3 h-growth. At 24 h both Stx1 concentrations were equal or, in some strains, the ec resulted 2-fold higher that the ic. The ic-Stx1 was equal or just 2-fold higher that ec after 3 h-growth. However, at 24 h the released toxin level was 16 to 32 times higher that cell-bound toxin. The ec-Stx2c increased logarithmically, with maximal yields at 5 h, remaining constant up to 24 h. At that time ic-toxin was 2-fold higher than the released one. When the same experiments were performed on strains isolated from HUS patients they showed that the kinetic patterns obtained corresponded to Stx2. These results were confirmed by hybridization assays. In this study we have shown that Stx1 production decreases dramatically during stationary phase while Stx2 is detected at high level at that time. This could explain the higher frequency of association of Stx2-producing E. coli strains and HUS in some countries, including Argentina.