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A lytic bacteriophage, which was previously isolated from sewage and which attaches to the K1 capsular antigen, has been used to prevent septicemia and a meningitis-like infection in chickens caused by a K1+ bacteremic strain of Escherichia coli. Protection was obtained even when administration of the phage was delayed until signs of disease appeared. The(More)
Chickens were inoculated intravenously with 10(5) or 10(6) organisms. Heavy infection of the ovaries occurred and some infection persisted in this organ for several weeks. Most of the ovarian infections were confined to the interstitial tissues and not to the yolk contained in the large follicles. Infections of the ovary did not result from contamination(More)
Acute enteric infections caused by salmonellas remain a major public health burden worldwide. Poultry, particularly chickens, are known to be the main reservoir for this zoonotic pathogen. Although some progress has been made in reducing Salmonella colonization of broiler chickens by using biosecurity and antimicrobials, it still remains a considerable(More)
Oral inoculation of 5-day-old gnotobiotic pigs with Salmonella enterica serovar Typhimurium strain F98 resulted in severe enteritis and invasive disease. Preinoculation 24 h earlier with an avirulent mutant of Salmonella enterica serovar Infantis (1326/28) completely prevented disease for up to 14 days (when the experiment was terminated). S. enterica(More)
BACKGROUND & AIMS How mutations are established and spread through the human stomach is unclear because the clonal structure of gastric mucosal units is unknown. Here we investigate, using mitochondrial DNA (mtDNA) mutations as a marker of clonal expansion, the clonality of the gastric unit and show how mutations expand in normal mucosa and gastric mucosa(More)
Bacteriophages lytic for Salmonella typhimurium were isolated in considerable numbers from chickens experimentally infected with S. typhimurium, and in much lower numbers from the chicken feed. Lytic phages were also regularly isolated from human sewerage systems. One of these was used to inoculate S. typhimurium--infected two day-old chickens orally and(More)
The virulence of Salmonella typhimurium strains for day-old chickens was examined. The mortality following oral inoculation varied from 0 to 100 per cent. Some breeds were more susceptible than others. There was no correlation between oral and parenteral virulence. Pathogenesis studies associated with one of the most virulent strains suggested that, after(More)
From a collection of 2,800 Tn5-TC1 transposon mutants of Salmonella typhimurium F98, 18 that showed reduced intestinal colonization of 3-week-old chicks were identified. The sites of transposon insertion were determined for most of the mutants and included insertions in the lipopolysaccharide biosynthesis genes rfaK, rfaY, rfbK, and rfbB and the genes dksA,(More)
Following oral inoculation of newly-hatched or three-week-old chickens, Salmonella organisms persisted longest in the caeca and they were also present for a shorter time in the crop. S. cholerae-suis, E. coli K12 and Saccharomyces cerevisiae did not colonise the alimentary tract when inoculated orally, but they persisted longer in the caeca than in other(More)
We investigated the attenuating effects of a range of respiratory chain mutations in three Salmonella serovars which might be used in the development of live vaccines. We tested mutations in nuoG, cydA, cyoA, atpB, and atpH in three serovars of Salmonella enterica: Typhimurium, Dublin, and Gallinarum. All three serovars were assessed for attenuation in(More)