Diagnosis of Clostridium difficile infection: the molecular approach.

Diagnosis of Clostridium difficile infection is based on clinical presentation and laboratory tests. Although numerous laboratory methods are now available, the diagnosis of C. difficile infection remains challenging. Nucleic acid amplification tests (NAATs) are the most recent marketed methods. These methods detect genes for toxins A and/or B. They are very sensitive compared with the reference method (toxigenic culture) and are thus very promising, despite their cost. However, a positive NAAT result must be interpreted with caution owing to the possible detection of asymptomatic carriers of toxigenic strains who may have diarrhea for other reasons. The place of NAATs in current diagnostic strategies needs to be better defined, but the rapidity of the result is interesting for early recognition of the disease.