A total of 224 strains of Clostridium botulinum (including isolates from 14 patients with infant botulism and 4 with wound botulism) and 15 strains of C. sporogenes were tested by agar dilution for susceptibility to tetracycline, metronidazole, erythromycin, penicillin, rifampin, chloramphenicol, clindamycin, cephalothin, cefoxitin, vancomycin, sulfamethoxazole-trimethoprim, nalidixic acid, and gentamicin. At least 90% of the C. botulinum strains tested (except for nonproteolytic strains of toxin type F with penicillin) were susceptible to all drugs except sulfamethoxazole-trimethoprim, nalidixic acid, and gentamicin. Minimal inhibitory concentrations for strains from patients with infant and wound botulism were similar to those for other C. botulinum strains.Botulism is a neuroparalytic disease caused by neurotoxin produced by Clostridium botulinum. In 1951, the first three cases of wound botulism (two of the cases had occurred several years earlier) were reported (7,12,26). Before that, botulism .was considered strictly a foodborne illness. In 1976 another form of the disease known as infant botulism was recognized as a clinical entity (16,18). Foodborne botulism involves ingestion of preformned toxin in contaminated food. In vivo growth of C. botulinum is generally not considered to be a factor in the illness, although the possibility has been suggested on the basis of some clinical and laboratory observations (15,17). Although antimicrobial therapy is at present not recommended for botulism, the recognition of wound botulism and infant botulism has revived interest in its possible role for treatment of these infections (6). Because of the attention on these more recently recognized forms of botulism and because antimicrobial therapy might be considered, we felt it appropriate to determine the susceptibility of these organisms to antimicrobial agents. The information should also be useful in comparing isolates of C. botulinum from different sources and in formulating selective media for isolation of these organisms.
MATERIALS AND METHODSMedia and characterization procedures. Fortions for media used in these studies for the isolation, characterization, and storage of anaerobic bacteria are given by Dowell and Hawkins (9