In-Vitro Adhesion and Invasion Properties of Salmonella Typhimurium Competing with Bacteriophage in Epithelial Cells and Chicken Macrophages

Abstract

This study was designed to assess the role of bacteriophage P22 in the adhesion, invasion, intracellular survival of, and cellular immune response to Salmonella Typhimurium in intestinal epithelial INT-407 and chicken macrophage-like HD11 cells. The ability of S. Typhimurium to adhere, invade, and survive to INT-407 and HD11cells was evaluated under Salmonella infection alone (control), phage treatment followed by Salmonella infection (PS), Salmonella infection followed by phage treatment (SP), and a combination treatment with Salmonella and phage (S+P). The number of S. Typhimurium associated on INT-407 cells was reduced from 4.2 to 2.7 log cfu/cm 2 by phage treatment (SP). The number of intracellular S. Typhimurium within INT-407 cells was significantly reduced to below the detection limit (0.7 log cfu/cm 2 ) compared with the control (3.4 log cfu/cm 2 ). S. Typhimurium remained inside HD11 cells at 49% and 17% levels in the absence and presence of phages, respectively, at 24 h post-infection (hpi). The expression levels of IFN-g, IL-10, IL-1b, IL-6, IL-8, iNOS, and IL-12 increased in HD11 cells regardless the absence and presence of phages, while those of IL-16, TLR2-1, TLR3, and TLR7 were decreased at 0 and 24 hpi. This study sheds new light on our understanding of the role of phages in Salmonella adhesion, invasion, survival, and cellular immune responses.

Deletion of the lon gene augments expression of Salmonella Pathogenicity Island (SPI)-1 and metal ion uptake genes leading to the accumulation of bactericidal hydroxyl radicals and host pro-inflammatory cytokine-mediated rapid intracellular clearance

“…During the infection process, Salmonella will make contact with the host cell by attaching to the host cell through their receptors, and the level of adhesion and invasion are the very first virulence determinants for successful infection. 25,26 The adhesion and invasion studies conducted on non-phagocytic HeLa, HepG2 and Caco-2 cells revealed the lon deletion significantly increased (approximately 2-fold increase) both adhesion and invasion into the host cell. This was confirmed by CFU counting and by fluorescence microscopy.…”

Salmonella Bacteriophage Diversity According to Most Prevalent Salmonella Serovars in Layer and Broiler Poultry Farms from Eastern Spain

“…In addition, the vaccination programme is stricter in the Valencia region where, since 2008, it is mandatory to vaccinate not only against S. Enteritidis, but also against S. Typhimurium [19]. Live vaccination in poultry maintains the Salmonella vaccine strain in birds, as well as the house environment [34][35][36], and could encourage phage presence in the field. In this context, the latest data recovered from official checks in the Valencia region showed that 100% of S. Enteritidis strains isolated from rearing layers were S. Enteritidis vaccine strains (unpublished data).…”

Characterizing Phage-Host Interactions in a Simplified Human Intestinal Barrier Model

“…We were also able to examine the viability of the eukaryotic cells and the integrity of the epithelial barrier in the presence and absence of phage. A number of recent studies have used in vitro cell culture models to test the behavior of phage in the gut and their activity against intestinal pathogens [ 60 , 61 ]. To date, most have used single cell monolayers without a mucus layer [ 60 , 61 ].…”

“…A number of recent studies have used in vitro cell culture models to test the behavior of phage in the gut and their activity against intestinal pathogens [ 60 , 61 ]. To date, most have used single cell monolayers without a mucus layer [ 60 , 61 ]. More complex models using co-cultures have been utilized for the interaction of the phage with the epithelial layer.…”