No description available.

The prevention and control of salmonellae in commercial swine operations are becoming increasingly important. The current approach focuses on identifying sources and/or origins of salmonellae contamination before swine are processed for human consumption. The objective of the current study was to assess strain variability among salmonellae grouped by serotype and to determine common origins of contamination (farm or slaughter plant). Salmonellae were previously collected from swine at slaughter, serotyped by the National Veterinary Services Laboratory and stored at - 70??C. Pulsed-field gel electrophoresis (PFGE) was performed to genotypically characterize serotypic isolates using restriction endonuclease XbaI. Dendrogram comparisons were also used to assess genotypic similarity when multiple genotypes existed. This study found PFGE to be more discriminatory than serotyping indicating that multiple genotypic strains existed among selected serotypes. On the basis of PFGE results alone, origins of contamination could not be determined in this study. It is suggested by the author, that origins of contamination could be further defined pending future research, in which in-depth longitudinal studies are included. When used as an adjunct to conventional typing methods, PFGE may prove to be a substantial subtyping system in epidemiologic investigations to identify point-of-entry contaminants to the food chain.

The prevention and control of salmonellae in commercial swine operations are becoming increasingly important. The current approach focuses on identifying sources and/or origins of salmonellae contamination before swine are processed for human consumption. The objective of the current study was to assess strain variability among salmonellae grouped by serotype and to determine common origins of contamination (farm or slaughter plant). Salmonellae were previously collected from swine at slaughter, serotyped by the National Veterinary Services Laboratory and stored at - 70??C. Pulsed-field gel electrophoresis (PFGE) was performed to genotypically characterize serotypic isolates using restriction endonuclease XbaI. Dendrogram comparisons were also used to assess genotypic similarity when multiple genotypes existed. This study found PFGE to be more discriminatory than serotyping indicating that multiple genotypic strains existed among selected serotypes. On the basis of PFGE results alone, origins of contamination could not be determined in this study. It is suggested by the author, that origins of contamination could be further defined pending future research, in which in-depth longitudinal studies are included. When used as an adjunct to conventional typing methods, PFGE may prove to be a substantial subtyping system in epidemiologic investigations to identify point-of-entry contaminants to the food chain.

The Salmonella enterica subsp. enterica serovar Typhimurium PhoPQ two-component system is activated within the intracellular phagosome environment, where it promotes remodeling of the outer membrane and resistance to innate immune antimicrobial peptides. Maintenance of the PhoPQ-regulated outer membrane barrier requires PbgA, an inner membrane protein with a transmembrane domain essential for growth, and a periplasmic domain required for PhoPQ-activated increases in outer membrane cardiolipin. Here, we report the crystal structure of cardiolipin-bound PbgA, adopting a novel transmembrane fold that features a cardiolipin binding site in close proximity to a long and deep cleft spanning the lipid bilayer. The end of the cleft extends into the periplasmic domain of the protein, which is structurally coupled to the transmembrane domain via a functionally critical C-terminal helix. In conjunction with a conserved putative catalytic dyad situated at the middle of the cleft, our structural and mutational analyses suggest that PbgA is a multifunction membrane protein that mediates cardiolipin transport, a function essential for growth, and perhaps catalysis of an unknown enzymatic reaction. IMPORTANCE Gram-negative bacteria cause many types of infections and have become increasingly resistant to available antibiotic drugs. The outer membrane serves as an important barrier that protects bacteria against antibiotics and other toxic compounds. This outer membrane barrier function is regulated when bacteria are in host environments, and the protein PbgA contributes significantly to this increased barrier function by transporting cardiolipin to the outer membrane. We determined the crystal structure of PbgA in complex with cardiolipin and propose a model for its function. Knowledge of the mechanisms of outer membrane assembly and integrity can greatly contribute to the development of new and effective antibiotics, and this structural information may be useful in this regard.

In Legehennenbeständen wurde die Schutzwirkung von vier Impfprogrammen, die der Zentralverband der Deutschen Geflügelwirtschaft e.V. empfiehlt und einer Impfung nach der Hühner-Salmonellen-Verordnung untersucht. Unterschiede in den Impfschemata konnten unter den gewählten Versuchsbedingungen nicht festgestellt werden. Eine Impfung gegen Salmonellen garantiert keine vollständige Elimination des Erregers, sondern eine Reduktion der Besiedelung der Organe sowie der Ausscheidung und der Eikontamination. Auch eine zusätzliche Impfung mit Inaktivatimpfstoffen erbrachte keinen effektiveren Schutz vor Salmonella Enteritidis und Salmonella Thyphimurium. Die Schutzwirkung einer Impfung ist am besten, wenn die Salmonellen-Exposition gering ist.

In Legehennenbeständen wurde die Schutzwirkung von vier Impfprogrammen, die der Zentralverband der Deutschen Geflügelwirtschaft e.V. empfiehlt und einer Impfung nach der Hühner-Salmonellen-Verordnung untersucht. Unterschiede in den Impfschemata konnten unter den gewählten Versuchsbedingungen nicht festgestellt werden. Eine Impfung gegen Salmonellen garantiert keine vollständige Elimination des Erregers, sondern eine Reduktion der Besiedelung der Organe sowie der Ausscheidung und der Eikontamination. Auch eine zusätzliche Impfung mit Inaktivatimpfstoffen erbrachte keinen effektiveren Schutz vor Salmonella Enteritidis und Salmonella Thyphimurium. Die Schutzwirkung einer Impfung ist am besten, wenn die Salmonellen-Exposition gering ist.