Abstract
Detection of plasmid from leptospires and a comparison of the plasmid profiles between virulent and avirulent strains were performed to investigate whether leptospires contained plasmid(s) associated with virulence. Virulent strains of Leptospira interrogans serovars copenhageni, lai, canicola and pomona, which were virulent for the guinea pig and/or hamster and which showed chemotaxis toward hemoglobin, contained approximately 370 kilobases (kb) plasmid. Avirulent strains of L.interrogans also contained identical plasmid. Similar plasmid profiles in virulent and avirulent strains of L.interrogans were observed. These data showed that no plasmids associated with virulence or chemotaxis were detected. Strains of saprophytic leptospires, L.biflexa and Leptonema illini, did not possess any plasmid.
