Molecular epidemiology. PCR ribotyping banding patterns for 16 unique C. difficile RTs analyzed in this study (n = 207). The corresponding toxin gene profile is also provided. Origin: CLIN, clinical; VET, veterinary; ENV, environmental; RT, PCR ribotype; QX, novel RT assignment (internal nomenclature). Superscript a indicates the molecular epidemiology for some of these strains is based on previously published works (4, 36).