Susceptibility of Mycobacterium fortuitum to antibacterial agents as evaluated by disk diffusion and agar dilution methods.

The susceptibility of 34 strains of M. fortuitum to several antimicrobial agents was comparatively tested by the disk diffusion and the agar dilution methods. The results obtained by these two methods essentially showed that the microorganism was fully sensitive to amikacin and kanamycin and only partially sensitive to sisomicin and rifampicin. Streptomycin, erythromycin and cephotaxime were inactive. The disk diffusion method seems advisable as a rapid screening procedure for antibiotic susceptibility testing M. fortuitum.