Effect of nutrition on the respiratory virulence of Listeria monocytogenes.

Friedman, Mischa E. (U. S. Army Chemical Corps, Frederick, Md.) and Donald A. Kautter, Effect of nutrition on the respiratory virulence of Listeria monocytogenes. J. Bacteriol. 83:456-462. 1962.-The respiratory virulence for the mouse and guinea pig of two strains of Listeria monocytogenes grown in a rich nonsynthetic medium may be increased four to ninefold by decreasing the glucose concentration from 1.0 to 0.6% or by including 0.1% l-cysteine in the medium. This effect, not observed in intraperitoneal challenge of mice, is not due to selection of a more virulent population. Cultures demonstrating lowered virulence at 16 hr increase in virulence if incubated beyond 50 hr. The presence of 1.0% fructose or cellobiose results in the same growth and virulence characteristics as when glucose is used; however, cultures in media with 1.0% maltose are of decreased cell yield but increased virulence. Strain A4413 grown in media of low glucose concentration or in the presence of cysteine has greater oxidative activity than when grown in a medium of high glucose content. Other strains of lesser respiratory virulence, when grown in a low concentration of glucose, contain glucose dehydrogenase systems equal in activity with that of strain A4413.