Resumo

Leptospirosis is a zoonotic infectious disease which induces abortions, stillborn and weak offspring in cattle and causes serious economic losses worldwide. Serotyping has been used for many years for leptospires classification and still is used in many countries. However, modern technology including genotyping allows doing a better classification of these bacteria. Because of the high genetic variation present in this spirochete, the molecular typing of the prevalent pathogenic strains is important for the determination of surveillance, prevention and control strategies according to the actual epidemiological scenario. The purpose of this study was to molecularly genotype the pathogenic Leptospira strains isolated from clinical cases of cattle in Argentina. Methods: Genotyping was performed using the Multiple-Locus Variable-number tandem repeats Analysis (MLVA). This technique was used with one set of oligonucleotides specific for the pathogenic strain Leptospira interrogans sensu stricto. The following loci were used to discriminate the strains, VNTRS: 4, 7, 9, 10, 19, 23 and 31. Fifteen bovine-isolated strains were genotyped by MLVA obtaining the following results: 1. Two genotypes of Canicola Portlandvere and 8 genotypes of Pomona Pomona isolated from bovine abortions; 2. One genotype of Hardjo Hardjoprajitno and 2 genotypes of Canicola Hond Utrecht IV, from bovine kidneys from slaughterhouses; 3. Two genotypes of Icterohaemorrhagiae RGA isolated from kidneys of calves. These results show the wide range of genotypes present in the isolated Leptospira strains of in Argentinean cattle. In conclusion, it is recommended to use detailed surveys in all endemic regions in order to detect new genotypes and to analyze if new genotypes should be included in the current vaccines to prevent bovine leptospirosis according to the country or region.