RESUMEN
A real-time multiplex PCR assay was designed to amplify the virulence genes eae, pEAF, aatA, daaC, elt, est, ipaH, stx(1), and stx(2) for the detection of all diarrheagenic Escherichia coli pathotypes. This assay proved to be more sensitive and rapid than a conventional multiplex PCR for diarrheagenic E. coli isolates from children with diarrhea.
Asunto(s)
Técnicas Bacteriológicas/métodos , Escherichia coli/clasificación , Escherichia coli/aislamiento & purificación , Reacción en Cadena de la Polimerasa Multiplex/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Niño , Diarrea/diagnóstico , Diarrea/microbiología , Escherichia coli/genética , Infecciones por Escherichia coli/diagnóstico , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/genética , Genotipo , Humanos , Técnicas de Diagnóstico Molecular/métodos , Sensibilidad y Especificidad , Temperatura de Transición , Factores de Virulencia/genéticaRESUMEN
In a prospective study between February 2003 and June 2004, stool specimens of children less than 2 years of age with diarrhoea (n=218) and without diarrhoea (n=86), living in Vitória, Espírito Santo, Brazil, were examined for the presence of diarrhoeagenic Escherichia coli. E. coli isolates were tested by colony blot hybridization with specific DNA probes designed to detect EPEC, ETEC, EIEC, EAEC, DAEC and EHEC/STEC. Diarrhoeagenic E. coli strains were detected as the sole pathogen in stools of 92 (30.3 %) children, including 72 (33.0 %) with diarrhoea and 20 (23.2 %) without diarrhoea. DAEC was the most frequent pathotype and was found significantly more often from patients (18.3 %) than from controls (8.1 %) (P<0.05), particularly among children more than 1 year of age (P=0.01). Atypical EPEC and EAEC isolates were isolated from both patients (5.5 % and 4.6 %, respectively) and controls (6.9 % and 6.9 %, respectively). ETEC was more frequently isolated from patients (3.2 %) than controls (1.2 %). Typical EPEC (0.9 %) and EIEC (0.4 %) isolates were detected only in children with diarrhoea. In conclusion, our data suggest that DAEC should be considered potential pathogens in the region of Brazil studied.