Histopathological alterations due to different phylogroups of Escherichia coli isolated from clinical cases of bovine endometritis in rat model

In the present study, E. coli isolates representing four different phylogroups viz. A, B1, D, and F were used in rat model to study their pathogenic potential for the development of endometritis. Animal were classified into four infected groups and one group served as negative control. Isolates representing respective phylogroups were inoculated by intrauterine route in twenty diestrus rats. Histopathological changes noted in all the experimental groups with varying intensity of lesions of endometritis characterized by invasion of neutrophils in endometrial superficial epithelium, stratum compactum, uterine cavity, and microabscess formation. Experimental group 4 (phylogroup D) showed highest mean histopathological score, followed by group 2 (phylogroup A), group 3 (phylogroup B1) and group 5 (phylogroup F). However, no statistical significant difference could be observed between the infected groups. The present study concluded that, different phylogroups of E. coli do not differ significantly to induce the lesions of endometritis in diestrus rats.