Acidic metabolic products determined directly in clinical specimens of 51 anaerobic and 12 aerobic
infections by quantitative gas-liquid chromatography (GLC) were correlated with the bacteriologic findings. The presence of appreciable amounts of
succinic acid, more than 1 microM per ml, propionic and
isovaleric acid, at concentrations not exceeding 3 microM per ml, was strong evidence for Bacteroides fragilis
infections. When
isobutyric acid was also detected, a B. melaninogenicus
infection could be presumed. However, the presence of other anaerobes or aerobes could not be excluded. The presence of Clostridium spp. could also be presumed by the detection of
butyric acid at a concentration greater than 4 microM per ml and of acetic, propionic and
isobutyric acid at relatively high concentrations. In specimens from aerobic
infections, no other
acid except acetic and
lactic acid could be detected. Our data also show that quantitative GLC is not valid in Peptococcus and Peptostreptococcus spp.
infections except in some cases where Peptococcus alone or together with aerobic organisms are found.