Molecular and Phenotypic Analysis of the CS54 Island ofSalmonella entericaSerotype Typhimurium: Identification of Intestinal Colonization and Persistence Determinants

Abstract

The shdA gene is carried on a 25-kb genetic island at centisome 54 (CS54 island) of the Salmonella enterica serotype Typhimurium chromosome. In addition to shdA, the CS54 island of Salmonella serotype Typhimurium strain LT2 contains four open reading frames designated ratA, ratB, sivI, and sivH. DNA hybridization analysis revealed that the CS54 island is comprised of two regions with distinct phylogenetic distribution within the genus Salmonella. Homologues of shdA and ratB were detected only in serotypes of Salmonella enterica subsp. I. In contrast, sequences hybridizing with ratA, sivI, and sivH were present in S. enterica subsp. II and S. bongori in addition to S. enterica subsp. I. Deletion of the ratA and sivI genes did not alter the ability of Salmonella serotype Typhimurium to colonize the organs of mice. Insertional inactivation of the sivH gene resulted in defective colonization of the Peyer's patches of the terminal ileum but normal colonization of the cecum, mesenteric lymph nodes, and spleen. Deletion of the shdA gene resulted in decreased colonization of the cecum and Peyer's patches of the terminal ileum and colonization to a lesser degree in the mesenteric lymph nodes and spleen 5 days post-oral inoculation of mice. A strain containing a deletion in the ratB gene exhibited a defect for the colonization of the cecum but not of the Peyer's patches, mesenteric lymph nodes, and spleen. The shdA and ratB deletion strains exhibited a shedding defect in mice, whereas the sivH deletion strain was shed at numbers similar to the wild type. These data suggest that colonization of the murine cecum is required for efficient fecal shedding in mice.

Detection of virulence-associated genes in Salmonella Enteritidis isolates from chicken in South of Brazil

“…All of these isolates of S. Enteritidis were sivH gene positive. Although there are few studies on the frequency of this gene in populations of Salmonella spp., our results are similar to previous works (Kingsley et al 2003). Many of these effectors proteins were shown to play an important role in Salmonella virulence.…”

“…'s outer proteins (Sops) contribute to the invasion by these bacteria through the generation of membrane deformations (Hardt et al 1998) and the rearrangement of the cytoskeleton of the host cells (Galán & Zhou 2000). The sivH gene encodes an outer membrane protein associated with intestinal colonization (Kingsley et al 2003). Other important Salmonella spp.…”

Strain-resolved community genomic analysis of gut microbial colonization in a premature infant

“…30_2 and C. koseri. In Salmonella Typhimurium, RatB (and ShdA, see below) are associated with cecal colonization and fecal shedding, and the gene encoding this protein exhibits strain-associated sequence variation in the form of variable-number direct repeats (33). If RatA were associated with similar phenotypes, then sequence variation between the two strains could explain differences in nichepartitioning and fecal abundance.…”

Type V Protein Secretion Pathway: the Autotransporter Story

“…Characterization of this mutant revealed that the insertion was present in a gene termed shdA and that the locus carrying shdA was inserted in the xseA-yfgK region relative to the E. coli K-12 chromosome (249). Sequencing of this region and flanking DNA revealed a pathogenicity island (PAI) of 25 kb, recently designated the CS54 island, which contained several genes including shdA, ratA, ratB, sivI, and sivH (247). In silico analyses of shdA demonstrated that the protein encoded by this gene possesses all the features of an autotransporter protein and has homology to AIDA-I, TibA, and another S. enterica autotransporter protein termed MisL (see below) (249).…”