Key reactions for identifying Clostridium septicum are demonstrated in the two quadrant plates in the images to the right. Included in the upper image are reactions for milk (casein) proteolysis (12 o'clock quadrant), glucose fermentation, DNAse hydrolysis, and starch hydrolysis, respectively, reading clockwise.
Milk (casein) hydrolysis and glucose fermentation are key reactions for the identification in the upper plate. These reactions include no proteolysis of milk, fermentation of glucose (yellow-red color along the inoculation streak), positive DNAse (reddish clearing around the streak), and an adverse reaction for starch.
The media in the quadrant plate shown in the lower image include gelatin hydrolysis (2 o'clock quadrant) and fermentation of mannitol, lactose, and rhamnose, respectively, reading clockwise.
Key reactions in the lower plate include hydrolysis of gelatin, fermentation of lactose (yellow pigment), and adverse reactions for mannitol and rhamnose (no pigment).
Most strains of C. perfringens hydrolyze starch and produce proteolysis of milk, the key reactions that distinguish C. septicum (negative). Reactions to the other tests do not distinguish between the two.
