Total DNA from the target organisms are cut with a restriction enzyme and the fragments are separated by agarose gel electrophoresis. The separated DNA is transferred to a hybridization membrane by Southern blotting and hybridized with labelled probes that are complementary to 16s and23 sRNA genes in E. coli. In this way, bands that harbour the ribosomal RNA genes are highlighted. Typing is based on the number and sizes of bands obtained.

Lane 1 is a molecular size marker (HindIII digested Lambda DNA).

Lanes 2 to 5 shows typing patterns obtained with the strains that are analysed. The strains in lane 3 and 4 show identical patterns.