Antimicrobial susceptibility of Bacillus anthracis.

22 Bacillus anthracis isolates were tested for susceptibility to 27 antimicrobial agents by agar dilution. All isolates were sensitive to penicillins and did not produce beta-lactamase. Although all isolates were sensitive to cefazolin, cephalothin, cephradine and cefoperazone 19 isolates were resistant to cefuroxime, 18 to cefotaxime, 18 to ceftizoxime, 9 to ceftriaxone and 21 to ceftazidime. All isolates were also found to be sensitive to other antimicrobials tested. The new antimicrobial agents, ofloxacin and ciprofloxacin showed very good activity with MICs of 0.03-0.06 mg/l.