Clostridium difficile is a species of Gram-positive bacteria of the genus Clostridium that causes diarrhea and other intestinal disease when competing bacteria are wiped out by antibiotics . Clostridium difficile ( from the Greek kloster ( Î Î '' Ï Ï Ï Î Ï ) , spindle , and Latin difficile , difficult ) , also known as `` CDF\/cdf '' , or `` C. diff '' , is a species of Gram-positive bacteria of the genus Clostridium that causes severe diarrhea and other intestinal disease when competing bacteria in the gut flora are wiped out by antibiotics .