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1.
Environ Microbiol ; 20(11): 4079-4090, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30450829

RESUMEN

Contaminated water is a major risk factor associated with the transmission of Salmonella enterica serovar Typhi (S. Typhi), the aetiological agent of human typhoid. However, little is known about how this pathogen adapts to living in the aqueous environment. We used transcriptome analysis (RNA-seq) and transposon mutagenesis (TraDIS) to characterize these adaptive changes and identify multiple genes that contribute to survival. Over half of the genes in the S. Typhi genome altered expression level within the first 24 h following transfer from broth culture to water, although relatively few did so in the first 30 min. Genes linked to central metabolism, stress associated with arrested proton motive force and respiratory chain factors changed expression levels. Additionally, motility and chemotaxis genes increased expression, consistent with a scavenging lifestyle. The viaB-associated gene tviC encoding a glcNAc epimerase that is required for Vi polysaccharide biosynthesis was, along with several other genes, shown to contribute to survival in water. Thus, we define regulatory adaptation operating in S. Typhi that facilitates survival in water.


Asunto(s)
Agua Dulce/microbiología , Viabilidad Microbiana , Salmonella typhi/crecimiento & desarrollo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Humanos , Mutagénesis , Plásmidos/genética , Plásmidos/metabolismo , Polisacáridos Bacterianos/biosíntesis , Salmonella typhi/genética , Salmonella typhi/metabolismo , Fiebre Tifoidea/microbiología
2.
PLoS Negl Trop Dis ; 10(2): e0004446, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26867150

RESUMEN

Salmonella enterica serovar Weltevreden (S. Weltevreden) is an emerging cause of diarrheal and invasive disease in humans residing in tropical regions. Despite the regional and international emergence of this Salmonella serovar, relatively little is known about its genetic diversity, genomics or virulence potential in model systems. Here we used whole genome sequencing and bioinformatics analyses to define the phylogenetic structure of a diverse global selection of S. Weltevreden. Phylogenetic analysis of more than 100 isolates demonstrated that the population of S. Weltevreden can be segregated into two main phylogenetic clusters, one associated predominantly with continental Southeast Asia and the other more internationally dispersed. Subcluster analysis suggested the local evolution of S. Weltevreden within specific geographical regions. Four of the isolates were sequenced using long read sequencing to produce high quality reference genomes. Phenotypic analysis in Hep-2 cells and in a murine infection model indicated that S. Weltevreden were significantly attenuated in these models compared to the classical S. Typhimurium reference strain SL1344. Our work outlines novel insights into this important emerging pathogen and provides a baseline understanding for future research studies.


Asunto(s)
Diarrea/microbiología , Filogenia , Infecciones por Salmonella/microbiología , Salmonella enterica/clasificación , Salmonella enterica/aislamiento & purificación , Animales , Asia Sudoriental/epidemiología , Proteínas Bacterianas/genética , Diarrea/epidemiología , Variación Genética , Humanos , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Fenotipo , Infecciones por Salmonella/epidemiología , Salmonella enterica/genética
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