Typhimurium, while chemotaxis genes were dispensable [11]. However, subsequent studies, with other strains have not been able to confirm the flagella phenotype [8, 12]. Flagella but not fimbriae and not motility were found to be essential for S. Enteritidis infections in chicken [13], and lack of flagella causes a disadvantage in the early stage of oral infection of rats and in cell culture invasion [14, 15]. Salmonella serovars have very different epidemiology and life style, just as they display obvious differences with regard to motility and chemotaxis. The commonly studied S. Typhimurium infects numerous hosts and displays phase variation of its flagella

antigens. The host-specific and host-adapted LY3039478 serovars, on the other hand, infect a single or few hosts, and do not rely on extra-animal survival to any great extend [16]. It may be that motility and chemotaxis play a different role during host pathogen interaction in different serovars, depending on their lifestyle. The current understanding of the importance of flagella and chemotaxis genes in Salmonella host pathogen interaction is derived from studies of S. Typhimurium and S. Enteritidis, and results based on these serovars are taken as general for the genus.

Since the lifestyle differs markedly between ubiquitous serovars and the host-specific/host-adapted ones, we hypothesized that this may be a wrong assumption. In order to investigate Thiazovivin this, we characterized the importance of chemotaxis and flagella genes for host pathogen interaction of the host-adapted serovar S. Dublin compared to the well-characterized serovar S. Typhimurium. Results Interaction with epithelial cells Salmonella normally infects through the faecal oral route. Several studies have reported that flagella are important for the intestinal phase of infection, mostly based on studies

of the initial contact between RG7112 concentration cultured cells and flagella and motility mutants [8, 17]. In this study we compared the adhesion and invasion of a wild type strain of S. Dublin to the smooth swimming cheA mutant, the tumbling cheB mutant and a mutant without flagella (fliC mutant). The corresponding mutants of S. Typhimurium Fossariinae were used as reference points. The results are shown in Table 1. The S. Dublin flagella mutant (fliC) was significantly reduced in adhesion and invasion, the constitutively tumbling cheB mutant was reduced in invasion, while the constitutively smooth swimming (cheA mutation) only showed a slight, non-significant reduction of adhesion and invasion. As can be seen from the Table 1, the flagella phenotype paralleled that of the flagella-less S. Typhimurium mutant, while cheA-mutation caused significantly reduced invasion and cheB-mutation both reduced adhesion and invasion in this serotype. Table 1 Adhesion and invasion of S. Dublin (SDu) and S.