A 
TaqMan / 
MGB probe PCR (
polymerase chain reaction) technology can carry out bacterial 
genus identification on 
clostridium difficile in fecal genomes, simultaneously detect the carrying situation of 
toxin genes, and can judge whether a 
toxin A has deletion. A fecal specimen is not required to be purely cultured, and the strain identification and the 
toxin detection are completed in a 
reaction system. The method has the characteristics of simple operation, good 
repeatability, 
high flux detection specimens, short report time, and the like, and is applicable to the screening of 
pathogenesis of patients with 
diarrhea caused by clinically unexplained causes. The invention solves the technical problems that fecal specimens can be subjected to strain identification and strain toxin carrying situation screening simultaneously without being purely cultured, and 
a DNA (deoxyribonucleic acid) detection method for fecal genomes, which is high in sensibility, is provided. Because traditional anaerobic culture is uneasy to perform, and an 
enzyme immunoassay has methodology defects, according to the invention, the diagnosis rate of 
clostridium difficile associated 
diarrhea is significantly increased. Meanwhile, the invention also can be applied to the monitoring of 
drug used in the process of treating the diseases.