마우스에서 listeria monocytogenes의 장관정착과 그 결정요인 I. Listeria monocytogenes의 장관정착성

Intestinal Colonization and Its Determinants by Listeria monocytogenes in Mice I. Intestinal Colonization of Listeria monocytogenes

The present study was designed to investigate the intestinal colonization characteristics of Listeria monocytogenes in mouse. Attempted for this purpose were colonization sites with respect to the minimal inoculation dose by oral route and colonization quotient in tested serovars in specific pathogen free (SPF) ICR mice. In mice infected by inoculation orally with 0.2ml of 5.g×10⁻⁷ CFU/ml of L. monocytogenes, the organism was isolated from all of the gastrointestinal tracts as range from 1.20 to 4.73 log CFU /g until 8 hrs after inoculation while it was scarcely isolated from organs except for cecum and colon. Particularly, the cecum was predominant colonizing site for the organism in which bacteria were isolated as highest population 48 hrs after inoculation. In determination of minimal bacterial dose for colonization in cecum, 10⁴ CFU of L. monocytogenes was required to establish colonization. The cecal colonization quotient was determined as from 3.7 to 4.1 in serovars HPB 4b, HPB 1/2a, HPB 1/2b, HPB 1/2c, B1 1, and BS5 4, and there were no significantly differences among serovars. When tested to know the organs for bacterial infection using such parenchymal organs as liver, spleen, heart, brain and uterus, L. monocytogenes was isolated exclusively from liver and spleen in 2 of six mice 2 days after inoculation. The organism was isolated from the same organs of all experimental animal 3 days after inoculation, whereas the numbers of infected mouse were diminished 5 days after inoculation. Some of the experimental mice died after nervous signs peculiar to listeriosis 8 days after inoculation and the organism was isolated from liver, spleen, heart and brain, which is supposed as hematogenous infection after oral inoculation.