Adaptation to the chicken intestine in Salmonella Enteritidis PT4 studied by transcriptional analysis.

The transcriptional changes that occurred in Salmonella enterica serovar Enteritidis during colonization of the alimentary tract of newly hatched chickens were studied. A whole genome oligonucleotide microarray was used to compare the expression pattern with that from bacteria cultured in nutrient broth in vitro. Amongst other changes Salmonella Pathogenicity Island (SPI)-1, SPI-2 and SPI-5 genes were up-regulated in vivo suggesting a close association with the mucosa during colonization. Particular attention was paid to genes associated with metabolism of dicarboxylic acids and to responses to high osmolarity. Association between the colonization phenotype and gene mutations indicated that the latter was more important as a contribution to the colonization phenotype.

Dhawi AA ，Elazomi A ，Jones MA ，Lovell MA ，Li H ，Emes RD ，Barrow PA ... -  《-》

Salmonella enterica subspecies enterica serovar Enteritidis Salmonella pathogenicity island 2 type III secretion system: role in intestinal colonization of chickens and systemic spread.

Wisner ALS ，Desin TS ，Koch B ，Lam PS ，Berberov EM ，Mickael CS ，Potter AA ，Köster W ... -  《-》

Microarray-based detection of Salmonella enterica serovar Enteritidis genes involved in chicken reproductive tract colonization.

Salmonella enterica serovar Enteritidis has developed the potential to contaminate table eggs internally, by colonization of the chicken reproductive tract and internalization in the forming egg. The serotype Enteritidis has developed mechanisms to colonize the chicken oviduct more successfully than other serotypes. Until now, the strategies exploited by Salmonella Enteritidis to do so have remained largely unknown. For that reason, a microarray-based transposon library screen was used to identify genes that are essential for the persistence of Salmonella Enteritidis inside primary chicken oviduct gland cells in vitro and inside the reproductive tract in vivo. A total of 81 genes with a potential role in persistence in both the oviduct cells and the oviduct tissue were identified. Major groups of importance include the Salmonella pathogenicity islands 1 and 2, genes involved in stress responses, cell wall, and lipopolysaccharide structure, and the region-of-difference genomic islands 9, 21, and 40.

Raspoet R ，Appia-Ayme C ，Shearer N ，Martel A ，Pasmans F ，Haesebrouck F ，Ducatelle R ，Thompson A ，Van Immerseel F ... -  《-》

Salmonella enterica serovar enteritidis pathogenicity island 1 is not essential for but facilitates rapid systemic spread in chickens.

Desin TS ，Lam PK ，Koch B ，Mickael C ，Berberov E ，Wisner AL ，Townsend HG ，Potter AA ，Köster W ... -  《-》

Salmonella enterica serovar Enteritidis colonization of the chicken caecum requires the HilA regulatory protein.

Invasion of Salmonella into intestinal epithelial cells is believed to be essential for the pathogenesis of Salmonella infections. Invasion is mediated by genes located on the Salmonella pathogenicity Island I (SPI-1), which are needed for assembling a type three secretion system, that mediates injection of bacterial proteins into the cytosol of epithelial cells, resulting in cytoskeletal rearrangements and as a consequence invasion. HilA is the key regulator of the Salmonella Pathogenicity Island I. To assess the role of hilA in colonization of gut and internal organs in poultry, animals were infected with 10(8) CFU of a delta hilA mutant of S. Enteritidis and its parent strain at day of hatch. Very low numbers of delta hilA mutant strain were able to colonize the internal organs shortly after infection, but they were not eliminated from internal organs at 4 weeks post-infection. At that time, the colonization level of the wild type bacteria in internal organs was decreased to the same low level compared with delta hilA mutant strain bacteria. Shedding of the delta hilA mutant strain and colonization of the caeca was seriously decreased relative to the parent strain starting from Day 5 post-infection. At 4 weeks post-infection, the delta hilA mutant strain was more or less eliminated from the chicken gut, while the parent strain was still shed to a high level and colonized the caeca to a high extent (more than 10(7) CFU/g). It is concluded that hilA is involved in long-term shedding and colonization of S. Enteritidis in the chicken caeca.

Bohez L ，Ducatelle R ，Pasmans F ，Botteldoorn N ，Haesebrouck F ，Van Immerseel F ... -  《VETERINARY MICROBIOLOGY》