S. P.S Agar 1082 Condalab

SPS Agar (Sulfite Polymyxin Sulfadiazine) is a moderately selective medium that is used to recover Clostridium perfringens from fresh or preserved foods and food ingredients. The medium was modified by Angelotti, to incorporate sulfadiazine and polymyxin B sulphate to the more recent Mossel formula for the recovery of Clostridium perfringens.

Casein peptone provides nitrogen, vitamins, minerals, and amino acids essential for growth and yeast extract is a source of vitamins, particularly of the B-group. Ferric citrate and sodium sulphite are H2S indicators. C. perfringens reduces the sulphite to sulphide which in turn reacts with the iron and forms a black iron sulphide precipitate, seen as black colonies. Polymyxin B sulphate and sulfadiazine are inhibitors to organisms other than Clostridium spp. Bacteriological agar is the solidifying agent.

A few microorganisms other than C. perfringens can also grow on SPS Agar so it is best to perform a Gram stain and look for spores. Many common microorganisms are totally or partially inhibited, but if they develop, they generally do not form black colonies nor spores, nor do they reduce nitrate and are non-motile Gram-positive vegetative bacilli.