Biosynthesis of Androgen from Cortisol by a Species of Clostridium Recovered From Human Fecal Flora

A hitherto unknown species of Clostridium, provisionally designated strain 19, was isolated from the fecal flora of a healthy human adult. This strain synthesizes a constitutive desmolase that cleaves the side chain of cortisol to form 11β-hydroxy-4-androstene-3,17-dione. The enzymatic conversion is best demonstrated in supplemented peptone broth and in prereduced brain-heart infusion broth. The fecal concentration of strain 19 is 107–108 cells/g. The strain adapts with difficulty to growth on Mueller-Hinton agar and Columbia agar base; colony formation is enhanced by the addition of 5% sheep blood. The organism is sensitive to penicillin G and resistant to tetracycline, chloramphenicol, clindamycin, and erythromycin.