First isolation of bacteriophages for a spirochaete: potential genetic tools for Leptospira

Three bacteriophages of the saprophytic aquicole bacterium Leptospira biflexa were isolated from sewage waters from the outskirts of Paris, France. These phages do not infect representative strains of the pathogenic species Leptospira interrogans, and their host range is restricted to serovar patoc of the saprophytic species. The phages were found to be lytic and no lysogenic state could be demonstrated. Electron micrographs showed that the phages were morphologically identical and had polyhedral heads and contractile tails. Their genomes were sensitive to restriction enzymes and consisted of double-stranded DNA. Pulsed-field agarose gel electrophoresis indicated that their genomes were linear: 60 kb for LE1 and 50 kb for LE3 and LE4.