The influence of native gut microflora on the colonization and infection of Salmonella gallinarum in chickens.

A native intestinal microflora of chickens that is protective against paratyphoid salmonellae appeared to be partially protective against Salmonella gallinarum and abbreviated the excretion time of S. gallinarum in White Leghorn chicks. Treated birds had a lower incidence of systemic infection measured by liver and spleen culture, and fewer birds developed infection in the intestinal tract. Most of the chickens positive by cloacal swabs excreted S. gallinarum throughout the test period. The low level of protection provided by competitive exclusion suggested that the practice would not prove useful in the practical control of fowl typhoid.