[Differences in susceptibility of mice among various strains to oral infection with Corynebacterium kutscheri]

Differences in susceptibility of female mice among 10 strains to Corynebacterium kutscheri infection were studied pathologically and bacteriologically. Twenty mice of each strain were inoculated orally with 4 x 10(5.0) CFU of the bacteria. The gross lesions were observed in 60.0% of BALB/c-nu/nu mice, 25.0% of CBA/N mice, 10.0% of MPS mice, and 5.0% of A/J and C3H/He mice, while BALB/cCr, C57BL/6Cr, B10.BR/SgSn, ddY and ICR mice showed neither clinical signs nor gross lesions. Six BALB/c-nu/nu, two CBA/N and one MPS mice died within 15 days after inoculation. C. kutscheri was recovered from 95.0% of BALB/c-nu/nu mice, followed by 75.0% of A/J mice, 65.0% of CBA/N mice, 55.0% of MPS and BALB/cCr mice, and 30% of C3H/He mice. On the other hand, from C57BL/6Cr, B10.BR/SgSn and ddY mice, the bacteria were recovered at less than 15.0% of the mice. No bacteria were recovered from ICR mice. C. kutscheri colonized most frequently in the cecum, colon and rectum. Number of mice having agglutinating antibodies were less than 20% and their antibody titers ranged from 1:10 to 1:80. These results indicated that there were differences in susceptibility of mice among the strains to oral infection of C. kutscheri. Namely, BALB/c-nu/nu, A/J, CBA/N, MPS and BALB/cCr mice appeared to be susceptible, and C3H/He mice intermediate, while C57BL/6Cr, B10.BR/SgSn, ddY and ICR resistant. BALB/c-nu/nu mice were most susceptible and exhibited markedly severe disease by the infection.