The Type VI Secretion System Encoded in SPI-6 Plays a Role in Gastrointestinal Colonization and Systemic Spread of Salmonella enterica serovar Typhimurium in the Chicken
Yang, Hee Jeong
Blondel, Carlos J.
Santiviago Cid, Carlos
Andrews Polymenis, Helene L.
Cita de ítem
PLoS ONE 8(5): e63917
Artículo de publicación ISI
The role of the Salmonella Pathogenicity Islands (SPIs) in pathogenesis of Salmonella enterica Typhimurium infection in the
chicken is poorly studied, while many studies have been completed in murine models. The Type VI Secretion System (T6SS)
is a recently described protein secretion system in Gram-negative bacteria. The genus Salmonella contains five
phylogenetically distinct T6SS encoded in differentially distributed genomic islands. S. Typhimurium harbors a T6SS
encoded in SPI-6 (T6SSSPI-6), which contributes to the ability of Salmonella to colonize mice. On the other hand, serotype
Gallinarum harbors a T6SS encoded in SPI-19 (T6SSSPI-19) that is required for colonization of chicks. In this work, we
investigated the role of T6SSSPI-6 in infection of chicks by S. Typhimurium. Oral infection of White Leghorn chicks showed
that a DT6SSSPI-6 mutant had reduced colonization of the gut and internal organs, compared with the wild-type strain.
Transfer of the intact T6SSSPI-6 gene cluster into the T6SS mutant restored bacterial colonization. In addition, our results
showed that transfer of T6SSSPI-19 from S. Gallinarum to the DT6SSSPI-6 mutant of S. Typhimurium not only complemented
the colonization defect but also resulted in a transient increase in the colonization of the cecum and ileum of chicks at days
1 and 3 post-infection. Our data indicates that T6SSSPI-6 contributes to chicken colonization and suggests that both T6SSSPI-6
and T6SSSPI-19 perform similar functions in vivo despite belonging to different phylogenetic families.