OLIGONUCLEOTIDES SPECIFIC FOR PATHOGENIC AND SAPROPHYTIC LEPTOSPIRA OCCURRING IN WATER

Sets of primers specific for both pathogenic (SPL) and saprophytic (SS L) Leptospira were designed from ribosomal 16S genes (I rs) available in databases. They were used as two sets of primer pairs for the PCR a mplification of known pathogenic and saprophytic strains. It was possi ble to identify pathogenic strains by the use of SPL primers and sapro phytic ones by SSL primers. Serovars from L. meyeri, of controversial pathogenicity status, confirmed the heterogeneity of the species repre sentatives in this respect. Serovars ranarum, sofia and perameles were amplified by SPL and not SSL. Conversely, serovar semaranga was ampli fied by SSL and not SPL. In order to use SPL primers for the detection of pathogenic leptospires from a natural water environment, we set up an additional semi-nested PCR by employing a second internal primer w hich succeeded in detecting as few as 5 pathogenic leptospires per ml of water.