Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea. Three adhesins (Tia, TibA, EtpA), an iron acquisition system (Irp1, Irp2, and FyuA), a GTPase (LeoA), and an autotransporter (EatA) are ETEC virulence-related proteins that, in contrast to the classical virulence factors (enterotoxins and fimbrial colonization factors) have not heretofore been targets in characterizing isolates from epidemiological studies. Here, we determined the occurrence of these nonclassical virulence genes in 103 ETEC isolates from Chilean children with diarrhea and described their association with O serogroups and classical virulence determinants. Because tia, leoA, irp2, and fyuA are harbored by pathogenicity islands inserted into the selC and asnT tRNA genes (tDNAs), we analyzed the regions flanking these loci. Ten additional tDNAs were also screened to identify hot spots for genetic insertions. Associations between the most frequent serogroups and classical colonization factor (CF)-toxin profiles included O6/LT-STh/CS1-CS3-CS21 (i.e., O6 serogroup, heat-labile [LT] and human heat-stable [STh] enterotoxins, and CFs CS1, -3 and -21), O6/LT-STh/CS2-CS3-CS21, and O104-O127/STh/ CFAI-CS21. The eatA and etpA genes were detected in more than 70% of the collection, including diverse serogroups and virulence profiles. Sixteen percent of the ETEC strains were negative for classical and nonclassical adhesins, suggesting the presence of unknown determinants of adhesion. The leuX, thrW, and asnT tDNAs were disrupted in more than 65% of strains, suggesting they are hot spots for the insertion of mobile elements. Sequences similar to integrase genes were identified next to the thrW, asnT, pheV, and selC tDNAs. We propose that the eatA and etpA genes should be included in characterizations of ETEC isolates in future epidemiological studies to determine their prevalence in other geographical regions. Sequencing of tDNAassociated genetic insertions might identify new ETEC virulence determinants.Enterotoxigenic Escherichia coli (ETEC) causes nearly 400 million diarrhea episodes every year in children younger than 5 years of age and is responsible for approximately 50% of all traveler's diarrhea episodes (35). ETEC colonizes the smallbowel epithelium, producing heat-labile (LT) and/or heat-stable (ST) enterotoxins (7) that cause secretion of water and electrolytes. Toxin variants LT-I and STh are produced only by strains that infect humans. LT-II and STp are expressed by strains that infect mostly piglets, although they occasionally also infect humans (20).Other classical ETEC virulence determinants are the colonization factors (CFs), also referred to as coli surface antigens (20), adhesins that direct colonization of the small bowel epithelium. Currently, 22 different putative ETEC CFs have been identified, designated CS followed by a number depending on their order of discovery, with the exception of CFAI, which maintains its original denomination (10, 31). The most prevalent CFs associated with the occurrence of diarrhea worldwi...

Introducción: El tamizaje de los Trastornos del Espectro Autista (TEA) mediante el Modified Checklist for Autism in Toddlers - Revised with Follow Up (M-CHAT-R/F) aumenta la detección precoz, posibilitando intervenciones tempranas y mejorando el pronóstico. Este instrumento es parte del algoritmo de manejo ante la sospecha de TEA en diversas guías clínicas. El objetivo fue realizar la validación concurrente, discriminante y el análisis de confiabilidad del M-CHAT-R/F en una población chilena.Pacientes y Método: Esta es la segunda etapa de la adaptación transcultural, de diseño transversal. Se aplicó M-CHAT-R/F a una muestra de 20 niños con sospecha de TEA y 100 niños de control sano seleccionados al azar, de 16-30 meses de edad. Se aplicó Autism Diagnostic Observation Schedule (ADOS-2), considerado como referencia, a los 20 pacientes de la muestra clínica, a 20 niños de la muestra de control sano y a aquellos casos de la muestra de control sano con M-CHAT-R/F positivo. Se calculó alfa de Cronbach, análisis de correlación de M-CHAT-R/F y ADOS-2 y sensibilidad y especificidad.Resultados: En el grupo de control sano, M-CHAT-R/F resultó alterado en 2 pacientes, siendo uno positivo y otro negativo para TEA con ADOS-2. En muestra clínica el M-CHAT-R/F fue positivo en todos, con test de ADOS-2 negativo en 3 casos. La confiabilidad Alfa del M-CHATR/F fue =0,889, la sensibilidad y especificidad discriminante de 100 y 98% y la concurrente 100% y 87,5% respectivamente.Conclusión: M-CHAT-R/F en su versión chilena resultó fiable, sensible y específico de manera similar al original, lo cual abre la posibilidad de su utilización en población clínica y para investigación. La validación es un proceso continuo que se debe profundizar.

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