In fact, during the 1950's especially, Staphylococcus aureus was blamed for infections now known to have been caused by C. difficile. Diagnosis of C. difficile colitis generally requires isolation of the organism from stool samples although C. difficile is difficult to culture. The presence of other pathogens may be confusing and culture alone may not mean that the organism is releasing toxins. Immunoassays for the toxins should be made to confirm a positive Clostridium difficile toxin titer. Tissue cytotoxic assays are more sensitive than counter electrophoresis for detecting toxins.
Latex agglutination assays for toxins lack specificity often creating false positive results.
All sources agree that endoscopic observation of pseudomembranes in the colon is the means for confirmational diagnosis of pseudomembranous colitis caused by C. difficile. Not all diarrhea following antibiotic treatment is caused by C. difficile. Diarrhea may be a self limited condition that resolves with fluid, electrolyte support and cessation of antibiotic treatment. For mild to moderate episodes of colitis, oral metronifazole is the drug of choice as it is less expensive than oral vancomycin, has anti-anaerobic properties and avoids development of fecal enterococcal resistance to vancomycin that commonly occurs. Lomotil and other antiperistaltic agents should be avoided as they might pool toxic fluid in retained colonic contents and create a worse condition.