Clindamycin Protects Nonhuman Primates Against Inhalational Anthrax But Does Not Enhance Reduction of Circulating Toxin Levels When Combined With Ciprofloxacin. (22nd July 2020)

• Record Type: Journal Article
• Authors: Vietri, Nicholas J; Tobery, Steven A; Chabot, Donald J; Ingavale, Susham; Somerville, Brandon C; Miller, Jeremy A; Schellhase, Chris W; Twenhafel, Nancy A; Fetterer, David P; Cote, Christopher K; Klimko, Christopher P; Boyer, Anne E; Woolfitt, Adrian R; Barr, John R; Wright, Mary E; Friedlander, Arthur M
• Is Part Of: Journal of infectious diseases. Volume 223:Number 2(2021)
• Page Start: 319
• Page End: 325
• Publication Date: 2020-07-22
• Subjects: anthrax -- antibiotics -- treatment -- toxins -- clindamycin -- ciprofloxacin -- lethal factor -- protective antigen; Communicable diseases -- Periodicals; Diseases -- Causes and theories of causation -- Periodicals; Medicine -- Periodicals; Communicable Diseases -- Periodicals; Electronic journals; 616.9
• DOI: 10.1093/infdis/jiaa365
• Languages: English
• ISSNs: 0022-1899

Abstract

Abstract: Background: Inhalational anthrax is rare and clinical experience limited. Expert guidelines recommend treatment with combination antibiotics including protein synthesis-inhibitors to decrease toxin production and increase survival, although evidence is lacking. Methods: Rhesus macaques exposed to an aerosol of Bacillus anthracis spores were treated with ciprofloxacin, clindamycin, or ciprofloxacin + clindamycin after becoming bacteremic. Circulating anthrax lethal factor and protective antigen were quantitated pretreatment and 1.5 and 12 hours after beginning antibiotics. Results: In the clindamycin group, 8 of 11 (73%) survived demonstrating its efficacy for the first time in inhalational anthrax, compared to 9 of 9 (100%) with ciprofloxacin, and 8 of 11 (73%) with ciprofloxacin + clindamycin. These differences were not statistically significant. There were no significant differences between groups in lethal factor or protective antigen levels from pretreatment to 12 hours after starting antibiotics. Animals that died after clindamycin had a greater incidence of meningitis compared to those given ciprofloxacin or ciprofloxacin + clindamycin, but numbers of animals were very low and no definitive conclusion could be reached. Conclusion: Treatment of inhalational anthrax with clindamycin was as effective as ciprofloxacin in the nonhuman primate. Addition of clindamycin to ciprofloxacin did not enhance reduction of circulating toxin levels. Abstract : This study demonstrated clindamycin is effective in treating inhalational anthrax in nonhuman primates. Survival was not significantly different from treatment with ciprofloxacin. Clindamycin combined with ciprofloxacin did not enhance reduction of circulating toxin levels compared to treatment with ciprofloxacin alone.