Desarrollo de un método para determinar la concentración mínima inhibitoria en cepas de referencias de leptospiras

a method to determine the minimum inhibitory concentration for leptospiras was developed, since there is not a standard method to measure it at the international level. reference strains from the pathogenic complex l. interrogans and l. biflexa were used against penicillin, cyprofloxacine, chloramphenicol, rifampicine and tetracycline. the minimum inhibitory concentration was defined as the lowest concentration of antibiotic where it was observed the inhibition of the bacterial mobility by direct examination in dark field. ranges for penicllin were from 0.095 to 152 μg/ml, for tetracycline from 0.156 to 3.13 μg/ml, for chloramphenicol, from 0.08 to 12.52 μg/ml, for rifampicine from 0.08 to 1.56 μg/ml, and for cyprofloxacine from 0.15 to 2.4 μg/ml. the antibiotics that showed the lowest values were cyprofloxacine, rifampicine and tetracycline, whereas the most elevated value was obtained against chloramphenicol and penicllin. the strains from the serogroups circulating more frequently in cuba were used in this research. this study will allow in a near future to determine the antimicrobial susceptibility in autochthonous strains isolated from patients with leptospirosis at the national level.