Effect of heat and selected chemical disinfectants upon infectivity of spores of Bacillus piliformis (Tyzzer's disease).

Spores of Bacillus piliformis of rabbit origin were harvested from the yolk sac of previously inoculated hen's eggs and subjected to various heat or chemical disinfectant treatments. Subsequently, spores were tested for infectivity in embryonated eggs inoculated via the yolk sac route, and others were treated with trypsin and then tested in embryonated eggs. The spores were not affected by the heat treatment of 60 degrees C but were rendered noninfective with treatments of 70 degrees C and 80 degrees C. Infectivity was not restored by treatment with trypsin. Infectivity was not lost when spores were treated with a phenolic germicidal detergent, ethanol or either of two quaternary ammonium compounds containing 9% or 17% benzalkonium chloride. A graded effect was observed with formaldehyde solution and an iodophor. Spores were rendered noninfective after treatment with peracetic acid (1.0%) and a wetting agent, sodium alkylarylsulfonate or sodium hypochlorite solution (0.3%) for 5 minutes, and infectivity was not restored by trypsin treatment. The probable means of transmission of Bacillus piliformis was discussed and sodium hypochlorite solution (0.3%) was recommended as a surface disinfectant in animal facilities as an aid to the prevention and control of Tyzzer's disease.