Occurrence and genetic characterization of Shiga toxin-producing Escherichia coli on bovine and pork carcasses and the environment from transport trucks.

Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens causing severe diseases. The ability of STEC to produce disease is associated with Shiga toxin (Stx) production. We investigated the occurrence of STEC on bovine and pork carcasses and walls of trucks where they were transported, and we characterized virulence genes and serotypes of STEC strains. We compared the whole genomic sequencing of a STEC O157:H7 strain isolated from a bovine carcass in this work and a STEC O157:H7 strain isolated from a child with HUS, both isolated in 2019. We studied the relationship between these isolates and others collected in the database. The results show a 40% of STEC and two different serogroups were identified (O130 and O157). STEC O157:H7 were isolated from bovine carcasses and harbored stx2, eae, ehxA, katP, espP, stcE, ECSP_0242/1773/2687/2870/2872/3286/3620 and were classified as lineage I/II. In STEC non-O157 isolates, three isolates were isolated from bovine carcasses and harbored the serogroup O130 and one strain isolated from pork carcasses was O-non-typeable. All STEC non-O157 harbored sxt1 gene. The analysis from the whole genome showed that both STEC O157:H7 strains belonged to the hypervirulent clade 8, ST11, phylogroup E, carried the allele tir 255 T > A T, and they were not clonal. The analysis of information allows us to conclude that the STEC strains circulate in pork and bovine carcasses arriving in transport. This situation represents a risk for the consumers and the need to implement an integrated STEC control in the food chain.

[Surveillance of the dengue vector at its distribution limit. A collaborative experience between the scientific, municipal and citizen ambits]. / Vigilancia del vector del dengue en el límite de su distribución. Una experiencia colaborativa entre los ámbitos científico, municipal y ciudadano.

INTRODUCTION: In Argentina, during the last decade a southward expansion of the mosquito Aedes aegypti has been observed, accompanied by an expansion in the dengue transmission. The objective of this study was to assess the establishment of the dengue mosquito vector in a locality next to its distribution limits by a collaborative work among scientific, municipal and citizen ambits. METHODS: A vector surveillance system through ovitraps was implemented, and it was complemented by pictures and mosquitoes captured by citizens, and by the active search of breeding sites in different urban spaces of Tandil City, Argentina. RESULTS: The establishment of Aedes aegypti population in the city was demonstrated, both by ovitraps and citizen science contributions. This information made it possible to begin to make the problem visible among municipal authorities and citizens. DISCUSSION: Dengue is an invisible disease in localities in which the mosquito vector has been spreading during the last decade. The information produced by the entomological surveillance is the necessary basis to addresssocial communication to produce behavioral changes in the responsible authorities as well as in the families.

Introducción: En Argentina, durante la última década se ha observado una expansión hacia el sur del mosquito Aedes aegypti, acompañada por la expansión en la transmisión del dengue. El objetivo de este estudio fue evaluar el establecimiento de Ae. aegypti en una localidad cercana al límite de su distribución mediante un trabajo colaborativo entre los ámbitos científico, municipal, y ciudadano. Métodos: Se implementó un sistema de vigilancia del vector mediante ovitrampas, el cual se complementó con fotografías y ejemplares aportados por los ciudadanos, y con búsqueda activa de criaderos del mosquito en distintos espacios urbanos de la ciudad de Tandil, Argentina. Resultados: Se demostró el establecimiento de una población de Ae. aegypti en el municipio, tanto por medio de las ovitrampas como por los aportes del conocimiento y participación de la comunidad: la ciencia ciudadana. La información obtenida permitió comenzar a visibilizar la problemática entre los funcionarios municipales y la ciudadanía. Discusión: El dengue es una enfermedad aún invisible en localidades donde se ha estado expandiendo el mosquito vector durante la última década. La participación pública y la información producida con la vigilancia entomológica es la base necesaria para abordar la comunicación social a fin de producir cambios de conducta en las autoridades responsables y en las familias.