Growth of Actinobacillus mallei in chemically defined media.

Abstract

A simple, chemically defined liquid medium containing phosphate buffer, magnesium and ferrous sulfates, glucose, and tribasic ammonium citrate supported excellent growth of a virulent strain of Actinobacillus mallei. When growth was measured turbidimetrically, a comparison of the rates of growth in media containing different initial concentrations of hydrogen ion (pH 6.3 and 6.6), phosphate buffer (0.05 M and 0.08 M), glucose (0.05 M and 0.10 M), and ammonium citrate (0.01 M and 0.02 M) indicated that the lower concentration of phosphate, glucose, and citrate and pH 6.3 favored early growth. The higher concentration of glucose favored an increase in cell mass during the early stationary phase unaccompanied by a comparable increase in viable cells. The highest viable cell count was attained in a medium containing 0,08 M KH2PO4–K2HPCO4, 0.05 M glucose, 0.02 M ammonium citrate, 0.000005 M Fe++, and 0.001 M Mg++ after 45 hours incubation, during which time the viable cell concentration rose from 1.6 × 107 to 1.5 × 1010/ml.