Metabolism of Pathogenic Clostridia in Complex Carbohydrate-Rich Culture Media. ∗

Abstract

One of the characteristics of the pathogenic and many of the non-pathogenic clostridia is their marked ability to digest and further metabolize proteins and protein derivatives during growth in the usual culture media. 1 2 3 4 5 Ammonia, volatile acids, CO₂, and H₂ are produced during the anaerobic breakdown of proteins and amino acids. 1 2 3 4 5 6 7 Carbohydrates are the source of most of the energy in carbohydrate-rich media,† and large quantities may be consumed, due to the formation of neutral compounds, CO₂ and H₂. Dextrose yields ethyl alcohol and formic (CO₂ and H₂), acetic, butyric, and lactic acids. 2 8 9 10 11 In the later stages of the fermentation the commercially important clostridia may yield very large quantities of acetone, and iso-propyl and butyl alcohols. 3 9 12 The same products may be obtained from lactic and pyruvic acids. 13 14 15 Acetic acid may be converted into acetone and butyl alcohol. 12 The presence of acetone and the higher alcohols in cultures of pathogenic clostridia has not been reported. Acrolein is found in cultures of Cl. perfringens (welchii) in glycerol broth. 16 The presence of acrolein in fruit juices and the bitterness of wine have been attributed to the growth of this organism. 17 Acetone may be reduced to iso-propyl alcohol; 18 aldehydes and acids are reduced to alcohols; 2 15 18 19 20 and acetaldehyde may yield acetylmethyl carbinol. 20 The clostridia thus appear to be versatile in their abilities to carry out chemical reactions with a wide variety of substances.

A comparative quantitative study of the metabolism of the pathogenic clostridia under identical conditions of growth has never been made, nor have the principal products of metabolism in the usual liquid media with added dextrose been determined. In the present paper, data from 5 species of pathogenic clostridia are presented.