Dissemination of a phage-encoded virulence factor in a pandemic S. Typhimurium

Abstract

Salmonella Typhimurium is the second most common cause of foodborne salmonellosis. Phage-mediated horizontal gene transfer contributes to the virulence of S. Typhimurium. An example of a phage-encoded virulence gene is sopE, a T3SS effector, found rarely in Typhimurium and associated with epidemics. The current pandemic and multi-drug resistant monophasic variant of S. Typhimurium (S. 4,[5],12:i:-) acquired sopE in multiple events following the lysogeny of a previously undescribed bacteriophage, mTmV. The current study aimed to further investigate the association of the virulence gene with S. 4,[5],12:i:- and assess its epidemiological impact. To this end, a large collection of clinical S. Typhimurium isolates from the UK have been analysed for the sopE gene and mTmV presence using a phylogenomic approach. While a large proportion of S. 4,[5],12:i:- (41 %) carried the sopE gene, few isolates outside the epidemic clade harboured it. Notably, the mTmV bacteriophage was identified only in S. 4,[5],12:i:-, although laboratory experiments demonstrated that the phage host range is not restricted to it. Nonetheless, we identified the phage in other S. enterica serovars circulating in the same ecological niche of S. 4,[5],12:i:-. In addition, a genomic characterisation of mTmV was performed revealing an unexpected level of phage variation. Finally, we identified a novel phage-like element harbouring the gene. The study revealed the large dissemination and selection of the virulence gene in the current epidemic, which is mobilised by multiple and distinct mobile genetic elements.

Sobrevida de Pacientes Pediátricos con Cardiopatía Congénita operados en Hospital María, Especialidades Pediátricas en 2017

“…Además, se estima que sin ningún tipo de intervención médica el 14% de los pacientes no sobrevive al primer mes de vida y el 30% al primer año. La tendencia actual es la realización de cirugía precoz y correctora, o paliativa realizadas antes del 1 año de vida para mejorar la morbimortalidad (4,5). Honduras por su parte cuenta con publicaciones que indican una incidencia de CC de 2.66 por cada 1000 nacidos vivos en el año 2006 en pacientes atendidos en el Instituto Hondureño de Seguridad Social (6).…”