Clostridium perfringens. Coloured Scanning Electron Micrograph (SEM) of Clostridium perfringens bacteria, cause of gas gangrene and food poisoning in humans. These rod-shaped bacilli bacteria are Gram-positive. They are commonly found living in soil where they form spores. Clostridium perfringens is the cause of several serious human disorders. The bacteria produces an exotoxin (alpha-toxin) capable of digesting human muscle and other tissues. It is the cause of gas gangrene in infected wounds. This bacteria can also contaminate food sources of meat, causing human blood poisoning and food poisoning. Magnification: x3750 at 6x7cm size.