Thermal Death Point: II. Spores of Bacillus Anthracis

Publisher Website
Google Scholar
Abstract
Effective temp. for destruction of spores of B. anthracis in physiologic saline were 105[degree], 100[degree], 95[degree] and 90[degree] C. At 105[degree], the time was 5-10 min., spores of most strains being destroyed in 5 min.; at 100[degree], 5-10 min., most spores being destroyed in 10 min.; at 95[degree], 10-25 min.; and at 90[degree], 15-45 min. Effective temp. for dry spores heated in absence of moisture were 135[degree], 130[degree], 125[degree] and 120[degree] (at 135[degree], 5-10 min.; at 130[degree], 15-20 min.; at 125[degree], 25 min.; and at 120[degree], 40-45 min). Dried spores heated under moist conditions showed no increased resistance, the effective temp. being 100[degree], 95[degree] and 90[degree]. Spores heated in Clark and Lubs'' buffer solutions showed best resistance in all cases at pH 8. Spores suspended in 1% peptone solution showed increased resistance as pH of solution increased. At pH 7, the greatest resistance seemed to be shown at a 1% peptone concentration. Resistance of spores suspended in NaCl solution seemed to decrease with increase in concentration of salt. In Clark and Lub''s buffer solutions, spores of Clostridium tetani showed greatest resistance at pH 7; spores of B. anthracis, at pH 8. In a 1% peptone solution, the best thermal resistance of spores of Cl. tetani occurred at about pH 7; resistance of B. anthracis spores increased as the pH value increased. At pH 7, as the concentration of peptone increased, the thermal death time of spores of Cl. tetani increased; with spores of B. anthracis, the greatest resistance seemed to occur at 1%. With spores of Cl. tetani, greatest resistance occurred at a salt concentration of 2%, while with spores of B. anthracis, the thermal death time seemed to decrease with increase in concentration.

This publication has 0 references indexed in Scilit: