Detección y caracterización de Escherichia coli productor de toxina Shiga en niños atendidos en un hospital pediátrico interzonal de la ciudad de La Plata

Abstract

Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen that can cause watery diarrhea, bloody diarrhea (BD), and hemolytic uremic syndrome (HUS). The objective of this study was to determine the phenotypic and genotypic profiles of STEC strains isolated from children with BD and HUS treated at a pediatric hospital in the city of La Plata in the period 2006-2012, and to establish the clonal relationship of O157:H7 isolates by pulsed field electrophoresis. The percentage of positive samples was 4.9% and 39.2% in patients with BD and HUS, respectively. Seventy-seven STEC strains from 10 different serotypes were isolated, with 100% colony recovery, O157:H7 being the most frequent (71.4%) serotype, followed by O145:NM (15.6%). An average of 98.2% of O157:H7 isolates belonged to biotype C and were sensitive to all the antibiotics tested. All of them (100%) carried genotype stx, eae, fliC, ehxA, iha, efa, toxB, lpfA1-3 and lpfA2-2. When the clonal relationship of the O157:H7 strains was studied, a total of 42 patterns with at least 88% similarity were identified, and 6 clusters with identical profiles were established. The eae-negative isolates belonged to serotypes O59:H19, O102:H6, O174:NM and O174:H21. The strains O59:H19 and O174:H21 were positive for the aggR gene. This study shows that STEC of different serotypes and genotypes circulate in the city of La Plata and surroundings. Despite the genetic diversity observed between the O157:H7 isolates, some were indistinguishable by the subtyping techniques used.

Surveillance of Shiga toxin-producingEscherichia coliassociated bloody diarrhea in Argentina

“…All STEC isolated were Stx2a-producing strains in combination with other stx subtypes and belonged to O157:H7 (3) and ONT:H2 (1) serotypes. These results are in agreement with previous studies, in which E. coli O157:H7 harboring the stx2a/stx2c genes was prevalent among diarrhea and HUS pediatric patients in Argentina (19,30,31). Recently, with the stx2a genotype as compared to the stx1a/stx2a genotype, two of the most common genotypes in USA and Japan (34,35,36).…”

Potential Zoonotic Pathovars of Diarrheagenic Escherichia coli Detected in Lambs for Human Consumption from Tierra del Fuego, Argentina

“…With regard to serotypes O102:H6, O81:H21, and O81:HNT, the first one was isolated in Argentina from a patient with mild and bloody diarrhea [ 40 ] and STEC O81:HNT was previously described in Tasmania isolated from raw pork [ 41 ], and from cattle in Australia (O81:H21) [ 42 ].…”

Perfiles genéticos bacterianos y análisis de brotes de las Enfermedades Transmitidas por Alimentos empleando Electroforesis de Campo Pulsado como herramienta para la vigilancia epidemiológica molecular

“…En referencia a las cepas de E. coli O157 y no O157 analizadas por esta técnica, es importante destacar la baja prevalencia de estos patógenos entéricos en nuestro país (23) y otros países como lo destaca Reyes et al 2013 (22) con un 0.8% y 2.6% para O157 y no O157 respectivamente. Hemos detectado gran diversidad genética; lo que también lo destacan Kalender et al 2016 (15) y Oderis et al 2018 (16) .…”

“…Kalender et al 2016 (15) , realizó la caracterización de Escherichia coli O157:H7 de cepas aisladas de heces de res por varios métodos moleculares incluyendo PFGE, destacó la diversidad genética de las cepas en estudio con varios patrones únicos y clusters detectados. Oderis et al 2018 (16) , caracterizó cepas de Escherichia coli productor de toxina shiga de muestras pediátricas detectando patrones con al menos un 88% de similitud y varios clusters que agruparon cepas con perfiles idénticos. El objetivo de estudio fue presentar la base de datos de perfiles genéticos bacterianos y analizar brotes de enfermedades transmitidas por alimentos empleando Electroforesis de Campo Pulsado.…”