OBJECTIVES: To investigate the in vitro acquisition of resistance to antibiotics by Bacillus anthracis. METHODS: The in vitro activities of 18 antibacterial agents against two strains of B. anthracis, the Sterne strain and the Russian anthrax vaccine strain ST-1, were tested by determining the MICs and by measuring the rates of antibiotic kill at 5x and 10x MIC. RESULTS: The fluoroquinolones ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin, the beta-lactams penicillin G and amoxicillin, the macrolide clarithromycin, the ketolide telithromycin, as well as clindamycin, rifampicin and quinupristin/dalfopristin had MICs in the range of 0.03-0.25 mg/L. Minocycline had an MIC of 0.03 mg/L, as did penicillin, against the ST-1 strain. Ciprofloxacin had an MIC of 0.03 mg/L against both strains. Erythromycin, vancomycin and the oxazolidinone linezolid were less active (MIC 0.5-2.5 mg/L). Ceftriaxone was the least active, having an MIC of 8.0 mg/L. Chloramphenicol was inactive (MIC > 256 mg/L). Quinupristin/dalfopristin, rifampicin and moxifloxacin showed the most rapid bacterial killing, achieving a complete eradication of detectable organisms (2 log(10) reduction within 0.5-3 h and 4 log(10) reduction within 0.5-4 h for both strains at concentrations of 5x and 10x the MIC). The beta-lactams and vancomycin demonstrated a 2-4 log(10) reduction within 5-15 h. Ceftriaxone had a similar effect to penicillin and amoxicillin against the ST-1 strain, but a slower effect than these two beta-lactams against the Sterne strain. The macrolides, tetracyclines and linezolid demonstrated a lower kill rate, while chloramphenicol did not kill at all. CONCLUSIONS: These data expand on the spectrum of agents recommended for the treatment of anthrax (ciprofloxacin, penicillin G and tetracyclines) and add new options, such as other fluoroquinolones, amoxicillin, rifampicin and quinupristin/dalfopristin, as potential therapeutic agents.
OBJECTIVES: To investigate the in vitro acquisition of resistance to antibiotics by Bacillus anthracis. METHODS: The in vitro activities of 18 antibacterial agents against two strains of B. anthracis, the Sterne strain and the Russian anthrax vaccine strain ST-1, were tested by determining the MICs and by measuring the rates of antibiotic kill at 5x and 10x MIC. RESULTS: The fluoroquinolonesciprofloxacin, ofloxacin, levofloxacin and moxifloxacin, the beta-lactamspenicillin G and amoxicillin, the macrolide clarithromycin, the ketolide telithromycin, as well as clindamycin, rifampicin and quinupristin/dalfopristin had MICs in the range of 0.03-0.25 mg/L. Minocycline had an MIC of 0.03 mg/L, as did penicillin, against the ST-1 strain. Ciprofloxacin had an MIC of 0.03 mg/L against both strains. Erythromycin, vancomycin and the oxazolidinonelinezolid were less active (MIC 0.5-2.5 mg/L). Ceftriaxone was the least active, having an MIC of 8.0 mg/L. Chloramphenicol was inactive (MIC > 256 mg/L). Quinupristin/dalfopristin, rifampicin and moxifloxacin showed the most rapid bacterial killing, achieving a complete eradication of detectable organisms (2 log(10) reduction within 0.5-3 h and 4 log(10) reduction within 0.5-4 h for both strains at concentrations of 5x and 10x the MIC). The beta-lactams and vancomycin demonstrated a 2-4 log(10) reduction within 5-15 h. Ceftriaxone had a similar effect to penicillin and amoxicillin against the ST-1 strain, but a slower effect than these two beta-lactams against the Sterne strain. The macrolides, tetracyclines and linezolid demonstrated a lower kill rate, while chloramphenicol did not kill at all. CONCLUSIONS: These data expand on the spectrum of agents recommended for the treatment of anthrax (ciprofloxacin, penicillin G and tetracyclines) and add new options, such as other fluoroquinolones, amoxicillin, rifampicin and quinupristin/dalfopristin, as potential therapeutic agents.
Authors: Karen E Brenneman; Mehmet Doganay; Arya Akmal; Stanley Goldman; Darrell R Galloway; Alfred J Mateczun; Alan S Cross; Leslie W Baillie Journal: FEMS Immunol Med Microbiol Date: 2011-04-15
Authors: Jarrod E Voss; Stephen W Scally; Nicole L Taylor; Sarah C Atkinson; Michael D W Griffin; Craig A Hutton; Michael W Parker; Malcolm R Alderton; Juliet A Gerrard; Renwick C J Dobson; Con Dogovski; Matthew A Perugini Journal: J Biol Chem Date: 2009-11-30 Impact factor: 5.157
Authors: Rekha G Panchal; Ricky L Ulrich; Douglas Lane; Michelle M Butler; Chad Houseweart; Timothy Opperman; John D Williams; Norton P Peet; Donald T Moir; Tam Nguyen; Rick Gussio; Terry Bowlin; Sina Bavari Journal: Antimicrob Agents Chemother Date: 2009-07-27 Impact factor: 5.191