Detection of Leptospiraceae by amplification of 16S ribosomal DNA

The polymerase chain reaction (PCR) was developed to detect Leptospiraceae. Primers were used to amplify 1 631 base-pair (bp) 5'-region of 16S rDNA. Representative strains from the species, Leptospira interrogans sensu stricto, L. borgpetersenii, L. noguchii, L. santarosai, L. weilii, L. inadai, L. meyeri and the single member strain of Leptonema were amplified. In contrast, strains representing the saprophytic species. L. biflexa, L. wolbachii and L. parva were not amplified. There was no PCR product from 23 phylogenetically unrelated species of bacteria. As little as 10-1 pg of purified DNA and as few as 10-1 leptospires could be detected using the PCR analysis. Isolates of leptospires from clinical sources gave a positive PCR band, but those from surface waters did not.