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Determinación de la estabilidad genética de una cepa de Mycobacterium bovis por infecciones seriadas en cobayos

2004; National Institute of Research for Forestry, Agricultural and Livestock; Volume: 42; Issue: 3 Linguagem: Inglês

10.22319/rmcp.v42i3.1408

2448-6698

Ana Marı́a Anaya Escalera, Camila Arriaga Díaz, Víctor Banda Ruíz, Feliciano Milián Suazo, Georgina Robles P., Carlos O. Serna González,

Bacterial Genetics and Biotechnology

This research was performed in order to determine the origin of the «direct repeat» (DR) region variability in one M. bovis strain when passed serially in ginea pigs. Three 6-guinea-pig groups were inoculated intraperitoneally with 103 M. bovis organisms/animal, using a strain isolated from a cattle lesion. Five weeks after inoculation the animals were killed. Tissue samples were obtained for M. bovis isolation. Fifteen of the 18 guinea pigs survived until sacrifice. All animals showed some type of lesion, and M. bovis was isolated from 14 of them. The molecular analysis was performed using the spoligotyping technique. The DNA from 13 isolates was harvested, out of which two clusters were obtained. The first cluster included six isolates: two from group 1, two from group 2, and two from group 3. The second cluster also included six isolates: three from group 1, two from group 2, and 1 from group 3. Each of the three reference strains (MTB, AN5, and h37rv), formed a different spoligotype. Two clusters were obtained specifically from the first group of guinea pigs: the first cluster includes three isolates, and the second cluster included three isolates. Once again, reference strains formed a different spoligotype. Results show that diversity in the DR region of M. bovis can occur in guinea pigs even if no external infections sources are present. This is likely to occur due to the generation of non-lethal mutations during bacterial reproduction, and this might be happening also in cattle.