RESUMO
Between July 1999 and December 2000, the prevalence of Shiga toxin-producing Escherichia coli (STEC) was established in 200 Argentine healthy young beef steers (14-16 months old) grown under local production systems with a feed grain period of 3-4 months, and the STEC strains isolated were examined in regard to their phenotypic and genotypic characteristics. Stool samples (n = 70) and rectal swabs (n = 130) were taken at the slaughterhouse level. By polymerase chain reaction (PCR), Shiga toxin (stx) gene sequences were detected in 69% of the samples. Eighty-six STEC strains were isolated from 39% of the animals. Serogroups identified, in order of frequency, were: O8 (16 strains), O113 (14), O103 (5), O91 (4), O171 (3), O174 (3), O25 (2), O112 (2), O145 (2), O2, O11, O104, O121, O128, O143, O146, O157. The most frequent serotype isolated was O8:H19 (12.9%). A total of 17 serotypes, including E. coli O157:H7 found in one animal (0.5%), have been previously associated with hemolytic uremic syndrome (HUS), bloody and non-bloody diarrhea in different countries, including Argentina. The prevalent genotype isolated was stx2 (51 of 86, 59.3%). Subtyping of stx2 variants showed the prevalence of stx2vh-b (25.6%) and stx2vh-a types (24.4%), and revealed the presence of an atypical stx2-v. Only 7.0% of STEC strains carried eae, and 33.7% harbored EHEC-hlyA gene. The full virulent genotype (stx/eae/EHEC-hlyA) was found to be present in 4 of the 86 (4.7%) STEC strains isolated. This research indicates that young steers from the main beef-producing area of Argentina are an important reservoir of STEC strains; however, its importance as agents of human diseases in our country has still to be established.
Assuntos
Doenças dos Bovinos/microbiologia , Reservatórios de Doenças/veterinária , Infecções por Escherichia coli/veterinária , Escherichia coli/patogenicidade , Toxina Shiga/biossíntese , Matadouros , Animais , Argentina/epidemiologia , Bovinos , Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Fezes/microbiologia , Masculino , Antígenos O/genética , Reação em Cadeia da Polimerase/métodos , Prevalência , Reto/microbiologia , Sorotipagem , Toxina Shiga/genética , VirulênciaRESUMO
Shiga toxin (Stx)-producing Escherichia coli (STEC) strains isolated from animals and food in Argentina (n=44) and Brazil (n=20) were examined and compared in regard to their phenotypic and genotypic characteristics to evaluate their pathogenic potential. The clonal relatedness of STEC O157 isolates (n=22) was established by phage typing (PT) and pulsed-field gel electrophoresis (PFGE). All O157 strains studied carried eae and enterohemorrhagic E. coli (EHEC)-hly sequences. In Argentina, these strains occurred both in cattle and meat, and 50% of them carried stx2/stx2vh-a genes, whereas in Brazil the O157 strains were isolated from animals, and most harbored the stx2vh-a sequence. At least 13 different O:H serotypes were identified among the non-O157 strains studied, with serotype O113:H21 being found in both countries. All but one non-O157 strains did not carry eae gene, but EHEC-hlyA gene was found in 85.7% of them, and the stx2 genotype was also more prevalent in Argentina than in Brazil (P<0.01), where stx1 alone or in association was most common (68.8%). One STEC strain isolated from a calf in Brazil harbored the new variant referred to as stx2-NV206. PFGE analysis showed that STEC O157 strains were grouped in four clusters. One Brazilian strain was considered possibly related (> or =80%) to Argentinean strains of cluster I. Differences in the pathogenic potential, especially in regard to serotypes and stx genotypes, were observed among the STEC strains recovered from animals and food in both countries.
Assuntos
Infecções por Escherichia coli/veterinária , Escherichia coli O157/genética , Microbiologia de Alimentos , Toxinas Shiga/genética , Adesinas Bacterianas/química , Adesinas Bacterianas/genética , Animais , Argentina , Brasil , Proteínas de Transporte/química , Proteínas de Transporte/genética , Bovinos , DNA Bacteriano/química , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado/veterinária , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/isolamento & purificação , Escherichia coli O157/metabolismo , Escherichia coli O157/patogenicidade , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Feminino , Proteínas Hemolisinas/química , Proteínas Hemolisinas/genética , Masculino , Carne/microbiologia , Hibridização de Ácido Nucleico , Filogenia , Análise de Sequência de DNA , Toxinas Shiga/químicaRESUMO
Between 9 October and 12 November 1996, an outbreak of bloody diarrhea occurred in the neonatal nursery ward of the Policlínico Neuquén, in Neuquén, a city in the southwestern region of Argentina. Seven patients of the intermediate care unit were affected. Isolates of Escherichia coli O18ac:H31 that were non-lactose and -sorbitol fermenting were recovered from outbreak cases. Although the strains were negative for a number of virulence factors typically found in diarrheagenic groups of E. coli, all isolates from the present neonatal outbreak possessed the enterohemolysin gene, ehl1. All isolates showed resistance to the antibiotics ampicillin and chloramphenicol. These isolates showed a low adherence property in HeLa cells without any recognizable pattern. In order to evaluate the outbreak dissemination in the neonatology ward, a prevalence study was conducted on 13 November. Stool specimens were obtained from 16 neonates hospitalized in the sector and from 33 medical staff members. E. coli isolates with identical biochemical characteristics of the outbreak strain were recovered from 11 of 16 inpatients and from 4 of 33 staff members during the prevalence study. A total of 15 E. coli strains recovered both from the outbreak and the prevalence study were processed by random amplified polymorphic DNA (RAPD)-PCR and pulsed-field gel electrophoresis (PFGE). By RAPD-PCR 14 of 15 strains showed patterns with 85 to 100% similarity, and by PFGE these strains were identical, each showing a unique pattern with 15 bands between 40 and 400 kb. One strain isolated from a nurse during the prevalence study presented a pattern not related to the others, and this was characterized as E. coli O81:HNM resistant to ampicillin only and negative for all the virulence factors studied. This outbreak occurred despite strict regulations in place to prevent cross-infection in the hospital. Postoutbreak prevalence studies were performed weekly thereafter without detecting new cases.
Assuntos
Diarreia/epidemiologia , Surtos de Doenças , Infecções por Escherichia coli/epidemiologia , Escherichia coli/classificação , Proteínas Hemolisinas/genética , Recém-Nascido Prematuro , Berçários Hospitalares , Animais , Argentina/epidemiologia , Diarreia/microbiologia , Eletroforese em Gel de Campo Pulsado , Escherichia coli/genética , Escherichia coli/patogenicidade , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli , Feminino , Proteínas Hemolisinas/metabolismo , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Prevalência , Técnica de Amplificação ao Acaso de DNA Polimórfico , SorotipagemRESUMO
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 Mendonza and from whom a Shiga toxin-producing Escherichia coli (STEC) 0127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Loboratory findings included: hematocrit, 35 per cent; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildy 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 per cent and blood urea nitrogen rose to 0.32 g/L. STEC 0127: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 knoweledge, on the isolation of E.coli 0127: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 managements 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
Humanos , Masculino , Criança , Toxinas Bacterianas/biossíntese , Infecções por Escherichia coli/complicações , Escherichia coli/isolamento & purificação , Hemorragia Gastrointestinal/microbiologia , Obstrução Intestinal/microbiologia , Abdome/microbiologia , Enterocolite/microbiologia , Infecções por Escherichia coli/diagnóstico , Escherichia coli/patogenicidadeRESUMO
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 Mendonza and from whom a Shiga toxin-producing Escherichia coli (STEC) 0127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Loboratory findings included: hematocrit, 35 per cent; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildy 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 per cent and blood urea nitrogen rose to 0.32 g/L. STEC 0127: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 knoweledge, on the isolation of E.coli 0127: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 managements 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. (AU)
Assuntos
Humanos , Masculino , Criança , Toxinas Bacterianas/biossíntese , Infecções por Escherichia coli/complicações , Hemorragia Gastrointestinal/microbiologia , Obstrução Intestinal/microbiologia , Escherichia coli/isolamento & purificação , Enterocolite/microbiologia , Abdome/microbiologia , Escherichia coli/patogenicidade , Infecções por Escherichia coli/diagnósticoRESUMO
Escherichia coli productor de toxina Shiga (STEC) ha sido asociado con la etiopatogenia del síndrome urémico hemolítico (SUH). El objetivo fue caracterizar los casos de SUH observados en Mendoza y determinar su asociación con la infección por STEC. Entre el 1º de Julio de 1994 y el 30 de Junio de 1996 ingresaron al Hospital Pediátrico "Dr. HJ Notti", 36 pacientes con diagnóstico de SUH. La edad promedio fue de 22.8 meses, con un 44 por ciento en el sexo femenino. La enfermedad se estableció después de un período prodrómico de 4.5 días, el 94.4 por ciento de los pacientes presentó diarrea siendo sanguinolenta en el 83.3 por ciento de los casos. El 69.4 por ciento recibió antibioticoterapia antes de su ingreso. Los casos se presentaron fundamentalmente en niños eutróficos (88.9 por ciento), de condición socioeconómica media-baja (91.7 por ciento) de origem urbano (72.2 por ciento), durante el verano y principios de otoño. En el período de estado los pacientes presentaron palidez (100 por ciento), edema (25 por ciento), anuria (38.9 por ciento), oliguria (41.7 por ciento), anemia hemolítica (97.2 por ciento), trombocitopenia (86.1 por ciento) y compromiso neurológico (41.7 por ciento). Veinticinco pacientes presentaron formas completas de SUH. El 50 por ciento de los pacientes fue dializado y el 88.9 por ciento requirió transfusión de sedimento globular. El promedio de días de internación fue de 15.1. El 91.7 por ciento de los pacientes recuperó la función renal, dos pacientes evolucionaron a insuficiencia renal crónica y uno falleció. Evidencias acumulativas de infección por STEC se encontraron en 19 (86.4 por ciento) de 22 pacientes, STEC del serotipo 0157:H7, biotipo C fue detectado en 8 casos (36.4 por ciento). Stx2 fue la citotoxina prevalente en STEC, en materia fecal (STMF) y anticuerpos a-Stx.
Assuntos
Humanos , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Toxinas Bacterianas , Escherichia coli , Infecções por Escherichia coli/complicações , Síndrome Hemolítico-Urêmica/microbiologia , Argentina , Síndrome Hemolítico-Urêmica/tratamento farmacológico , Síndrome Hemolítico-Urêmica/epidemiologia , Estado Nutricional , Fatores SocioeconômicosRESUMO
Escherichia coli productor de toxina Shiga (STEC) ha sido asociado con la etiopatogenia del síndrome urémico hemolítico (SUH). El objetivo fue caracterizar los casos de SUH observados en Mendoza y determinar su asociación con la infección por STEC. Entre el 1º de Julio de 1994 y el 30 de Junio de 1996 ingresaron al Hospital Pediátrico "Dr. HJ Notti", 36 pacientes con diagnóstico de SUH. La edad promedio fue de 22.8 meses, con un 44 por ciento en el sexo femenino. La enfermedad se estableció después de un perío