Abstract

Understanding the pathogenic status of leptospires, the causative agents of leptospirosis, is important for successful laboratory diagnosis and control programmes of this zoonosis. Leptospires are difficult to differentiate morphologically; therefore, their pathogenic, intermediate or saprophytic status is currently determined based on both phenotypic tests like growth response in medium containing 8-azaguanine and growth at low temperature (13°C), and genotypic methods. The present study reports on the pathogenic versus saprophytic characterization of nine Leptospira isolates from animal hosts (rodents and dogs) and humans, with specific interest on a canine isolate coded “Dog109”, which showed an ambiguous or intermediate status according to conventional (phenotypic) and molecular (genotypic) tests. The results strongly indicate the need of a polyvalent analytical approach for improving the differentiation of the pathogenic status of circulating serovars, particularly of fresh Leptospira isolates with an intermediate or controversial taxonomic position.

Key words: Characterization, isolates, Leptospira, leptospirosis, pathogenic, saprophytic.