[Development of the intratracheal infection model of experimental murine mycobacteriosis: comparison with the intravenous infection model].

An intratracheal infection method of experimental murine mycobacteriosis was developed for an in vivo study of antimycobacterial agents. Two models of intratracheal (IT) and intravenous (i.v.) routes of infection with mycobacteria of the same inoculum dose were compared in terms of the mean survival days of mice or bacterial loads in organs during the course of infection. IT model with either of M. bovis Ravenel, M. tuberculosis Kurono, M. tuberculosis H37Rv or M. intracellular N-256 exhibited a much more distinct lung-specific infection than i.v. model with the same dose of respective mycobacterial strains. The intratracheal infection method presented in this report does not require any special equipment and is a much safer method for the researcher than airborne infection. In this model, following slight anesthetizing of mice, bacillary suspension was injected quantitatively into lungs through the mouth and trachea by using a specially modified needle set with a short fine polyethylene tube. This IT model may be useful not only for the in vivo assessment of anti-mycobacterial agents but also for the comparison of virulence among various mycobacterial strains.