A 22-mer primer enhances discriminatory power of AP-PCR fingerprinting technique in characterization of leptospires

OBJECTIVES To evaluate the discriminatory power and usefulness of arbitrarily primed-polymerase chain reaction (AP-PCR) characterization of leptospires with M16 primer. METHODS AP-PCR fingerprints of 20 reference strains of Leptospira representing 20 different serovars belonging to seven genospecies (Leptospira interrogans, 11; L. noguchii, 2; L. borgpetersenii, 1; L. santarosai, 2; L. biflexa, 2; L. kirschneri, 1; L. weilii, 1) were generated by employing M16 primer. Fingerprints generated with this primer were compared with those generated with two other commonly used primers PB1, and L10. An attempt was also made to type 20 leptospiral isolates with the M16 primer. RESULTS AND CONCLUSION Fingerprints with M16 primer could not only differentiate between strains of different genospecies, but also between strains of the same genospecies belonging to different serovars. While two commonly used primers (PB1 and L10) failed to discriminate between some of the different serovars belonging to the same genospecies, this primer was able to generate discriminatory fingerprints for all strains tested. All 20 Leptospira isolates, recovered from patients in Andaman Islands, could also be typed by fingerprints generated with the M16 primer. The discriminatory power of M16 primer adds more specificity to the rapidity of this system of characterization and can be used as an excellent tool in epidemiological studies on Leptospira.