NOCARDIA-BRASILIENSIS - IN-VITRO AND IN-VIVO GROWTH-RESPONSE TO STEROID SEX-HORMONES

As actinomycetoma is more frequent in males than in females, the possi bility that hormones might modify the Nocardia brasiliensis growth and the course of experimental actinomycetoma was explored. Five N. brasi liensis strains were grown on Sabouraud agar containing estradiol, pro gesterone or testosterone, in 3 different concentrations. Colony diame ters were measured weekly for 7 weeks. N. brasiliensis strains were al so grown in Sabouraud broth containing hormones. Glucose concentration was measured weekly for 6 weeks. Finally, experimental actinomycetoma was produced in male and female hormone-treated mice. Invasion rate, plantar pad diameter and positive retrocultures were assessed. In vitr o experiments showed that progesterone and testosterone inhibit N. bra siliensis growth, manifested by lower colony diameters and greater glu cose concentrations. In vivo experiments demonstrated that estradiol l imits actinomycetoma development. Progesterone and testosterone induce d greater diameters of inoculated plantar pads and greater invasion ra tes with greater positive culture numbers than estradiol. Results part ially explain the resistance of females to actinomycetoma.