DNA fingerprinting by infrequent-restriction-site amplification.

Identification of bacterial strains by DNA fingerprinting facilitates epidemiologic studies and improves disease control. For some species of organisms, no typing method is available; for others, typing methods are tedious. We developed a method of amplifying DNA sequences flanking infrequent restriction sites by PCR and used the method to produce strain-specific electrophoretic patterns from crude bacterial lysates. This method of fingerprinting is rapid, sensitive, and widely applicable. Identical enzymes, adaptors, primers, and PCR conditions were used to characterize 32 Mycobacterium avium-M. intracellulare isolates, 4 Pseudomonas aeruginosa isolates, and 4 Staphylococcus aureus isolates.