RT Journal Article SR Electronic(1) A1 Brook, Itzhak A1 Giraldo, Dianet E A1 Germana, Antonino A1 Nicolau, David P A1 Jackson, William E A1 Elliott, Thomas B A1 Thakar, Jay H A1 Shoemaker, Michael O A1 Ledney, G DavidYR 2005 T1 Comparison of clarithromycin and ciprofloxacin therapy for Bacillus anthracis Sterne infection in mice with or without 60Co gamma-photon irradiation JF Journal of Medical Microbiology, VO 54 IS 12 SP 1157 OP 1162 DO https://doi.org/10.1099/jmm.0.46166-0 PB Microbiology Society, SN 1473-5644, AB Biological agents and ionizing radiation lead to more severe clinical outcomes than either insult alone. This study investigated the survival of non-irradiated and 60Co-gamma-irradiated mice given therapy for inhalation anthrax with ciprofloxacin (CIP) or a clinically relevant mixture of clarithromycin (CLR) and its major human microbiologically important metabolite 14-hydroxy clarithromycin (14-OH CLR). All B6D2F1/J 10-week-old female mice were inoculated intratracheally with 3 × 108 c.f.u. of Bacillus anthracis Sterne spores 4 days after the non-lethal 7 Gy dose of 60Co gamma radiation. Twenty-one days of treatment with CLR/14-OH CLR, 150 mg kg−1 twice daily, or CIP, 16.5 mg kg−1 twice daily, began 24 h after inoculation. Pharmacokinetics indicate that the area under the curve (AUC) for 14-OH CLR on the concentration-versus-time graph was slightly higher in gamma-irradiated than non-irradiated animals. Neither drug was able to increase survival in gamma-irradiated animals. CIP and CLR/14-OH CLR therapies in non-irradiated animals increased survival from 49 % (17/35 mice) in buffer-treated animals to 94 % (33/35) and 100 %, respectively (P < 0.001). B. anthracis Sterne only was isolated from 25–50 % of treated mice with or without irradiation. Mixed infections with B. anthracis Sterne were present in 50–71 % of gamma-irradiated mice but only in 5–10 % of mice without irradiation., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.46166-0