Direct quantitative determination of acidic end products in clinical specimens for presumptive diagnosis of anaerobic infections.

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.