title: [Therapeutic efficacy of a benzoxazinorifamycin, KRM-1648, administered at the different periods of infection in Mycobacterium intracellulare--infected mice].
abstract: Therapeutic efficacy of a newly synthesized benzoxazinorifamycin, KRM-1648, administered at the different periods of infection in Mycobacterium intracellulare-infected mice was studied. Mice were infected intravenously with M. intracellulare (9.8 x 10(6) CFU/mouse) and then were given 0.4 mg of KRM-1648 emulsified in 2.5% gum arabic-0.2% Tween 80 by gavage, once daily six times per week, from day 1 to week 4, week 2 to week 6, week 4 to week 8, and week 8 to the end of experiment (week 12). Judgement of the therapeutic efficacy of the drug against the infection was done on the basis of incidence and degree of gross lung lesions, % organ weight (organ weight/body weight x 100), and bacterial loads in the lungs and spleen. The lung lesions were not observed in the control and KRM-treated mice at 4 weeks after infection (KRM treatment: day 1 to week 4). At 6 weeks after infection (KRM treatment: week 2 to week 6), the lung lesions were observed in all control mice, whereas 3 of the 5 mice given KRM-1648 did not show the lesions. At 8 weeks after infection (KRM treatment: week 4 to week 8), the lung lesions were observed in all control and KRM-1648-treated mice, but the degree of the lung lesions was much more slight in mice given KRM-1648 than in control mice. The incidence and the degree of the lung lesions at 12 weeks after infection (KRM treatment: week 8 to week 12) was not different in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Microbiology and Immunology, Shimane Medical University, Izumo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tomioka
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: T
authors.initials: T
authors.lastname: Hidaka
mesh_terms: D000818:Animals; D000904:Antibiotics, Antitubercular / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009162:Mycobacterium avium; D012294:Rifamycins / Q000008:administration & dosage / Q000627:therapeutic use*; D013997:Time Factors; D014376:Tuberculosis / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000904:Antibiotics, Antitubercular; D012294:Rifamycins; C068980:KRM 1648