Pathology of experimental <i>Escherichia coli</i> infection in mice: a laboratory animal model for research in Matitis complex

Abstract

Bacterial mastitis frequently causes serious depressions of milk production and in certain cases may result in death in the dairy herd. Experimental bacterial mastitis served as a prelude to studying the actual infection in dairy cows. Cultures of nine serotypes of Escherichia coli isolated from various bacterial infections of animals were introduced into the gland cistern of normal lactating teats of mice. Each sereotype was inoculated in five log doses ranging from 10 to 105 colony-forming units (CFU). Each dose level was inoculated into three mammary glands of each of three mice. Mice were sacrificed after 72hrs and the glands examined bacteriological and histologically. Positive bacteriological and histological results were required for a diagnosis of infection. The infective dose fifty (ID50) for the nine stereotypes ranged from 39 to 12,000 CFU.The nine sereotypes designated as (1) highly virulent (2) moderately virulent and (3) weakly virulent. Histologically, the mastitis produced in mice resembles naturally occurring coliform mastitis in the cow. Global Journal of Mathematical Sciences Vol. 6 (1) 2007: pp. 17-24