Filtration of M. lepraemurium through Millipore Filter

Abstract

Bacillary suspension of M. lepraemurium was filtered through millipore filter type HA (pore size 0.45μ±0.02μ), type PH (pore size 0.30μ±0.02μ), type GS (pore size 0.22μ±0.02μ) and type VC (pore size 0.10μ±0.008μ) respectively under a pressure of 20mm Hg. Acid-fast bacilli in filtrates were examined microscopically after ultracentrif ugation (20, 000rpm, 45min.), and infectivity of filtrates was also examined by subcutaneous inoculation to mice.
Acid-fast bacilli were observed only in the filtrate through HA filter, and only this filtrate showed infectivity to mice. The other filtrates which were not observed acid-fast bacilli in them developed no murine leproma in mice.
Bacillary concentration of filtrate through HA filter was calculated as about 10⁴/ml by means of bacterial count and infectivity test by 10-fold dilution method.
It was concluded that it is needless to suppose the existance of special filtrable form of M. lepraemurium.