Metabolism of Pathogenic Bacteria Growing Under Aerobic Conditions in Carbohydrate-rich Culture Media. ∗

Abstract

Summary and Conclusions

Diplococcus pneumoniœ, Eberthella typhosa, and Escherichia coli were grown 24 hours at 37.5°C in meat infusion or meat extract culture medium enriched with 1% of peptone, 0.7 to 1.8% of Na₂HPO₄. 12 H₂O, and 1% of glucose. The pneumococcus was grown under anaerobic as well as highly aerobic conditions. The principal products were lactic acid, formic acid, acetic acid, and ethyl alcohol. The last 3 products appeared in the approximate ratio of 2 to 1 to 1. The reactions representing their formation most likely are: Glucose → hexose diphosphate → 2 triosephosphate → glycerophosphate and phosphoglycerate. Glycerophosphate → C₂H₅OH + HCOOH. Phosphoglycerate → phosphopyruvate → CH₃COOH + HCOOH. These are anaerobic mechanisms. Only a trace of CO₂ was obtained from pneumococci.

Rapidly growing bacteria may metabolize sugar almost entirely by anaerobic mechanisms when grown under relatively aerobic conditions. The same intermediary reactions are probably also utilized by microörganisms when growing in tissues in the course of an infection.