In Vitro Susceptibility of Bacillus anthracis to Antimicrobial Agents Including Carbapenems and Fosfomycin

Bacillus anthracis strains were tested for their in vitro susceptibilities to 25 antimicrobial agents, including carbapenems and fosfomycin. Ciprofloxacin, doxycycline, and amoxicillin were highly active against the B. anthracis strains, as reported earlier. Carbapenems as well as clarithromycin and clindamycin also showed considerable activity. Fosfomycin showed moderate levels of MIC against the B. anthracis strains, regardless of the presence of glucose-6-phosphate or blood. This glucose-6-phosphate-independent manner was also observed with the B. cereus strains. The data showed that, in addition to the drugs reported earlier, carbapenems are also active against B. anthracis, and that a fosfomycin-transport system in B. anthracis is distinct from the glucose-6-phosphate-inducible type in Escherichia coli or Stapylococcus aureus.