In Vitro Susceptibility of Mycobacterium fortuitum Complex to Cephem Antibiotics

The in vitro susceptibility of Mycobacterium fortuitum complex (30 strains of M. fortuitum, 30 strains of M. chelonei subsp. abscessus and 30 strains of M. chelonei subsp. chelonei) to 15 cephem antibiotics was studied on Kirchner's agar medium (containing 10% bovine serum). MIC90 (MIC at which 90% of strains were inhibited) of drugs against these organisms was 100 μg/ml or higher, however, cefoxitin and cefotetan were more active than the other compounds tested, against M. fortuitum strains.