Sex differences in susceptibility of ICR mice to oral infection with Corynebacterium kutscheri

Sex difference in susceptibility to oral infection with Corynebacterium (C. ) kutscheri was experimentally studied in ICR mice. Immature (4-week-old) a nd adult (14-week-old) mice were inoculated with two infecting doses of C. kutscheri, and necropsied for bacteriological and serological survey 4 week s after the bacterial infection. No macroscopic lesions at necropsy were de monstrated, except for one adult male given 10(9) bacteria. In immature mic e, C. kutscheri isolated from the oral cavity and cecum with FNC agar, were recovered in only 40.0% of female mice but in 90.0% of male mice given 10( 6) bacteria (p<0.05), and in only 55.6% of female mice but in 80.0% male mi ce given 10(8) bacteria. In adult mice given las bacteria, the organism wer e recovered in only 45.5% of female mice but in 90.9% of male mice (p<0.05) , furthermore, the mean number of organisms in the cecum of male mice harbo ring the organism was significantly higher than that in females (p<0.01). C astration caused an increase in host resistance in adult male mice. These r esults indicated that ICR male mice were more susceptible than females, in terms of bacterial colonization in the cecum and the oral cavity, to oral i nfection with C. kutscheri.