[On N2-fixing clostridia and bacilli from soils (author's transl)]

In total 30 nitrogen-fixing, saccharolytic Clostridia and 4 nitrogen-fixing bacilli, all freshly isolated from gleyed soils, were screened for sensitivity to 20 antibiotics. The isolates were compared in their sensitivity with 5 type cultures representing the species Clostridium butyricum, C. saccharobutyricum (2 strains) C. multifermentans and C. sporogenes. Generally speaking, both clostridia and bacilli are sensitive to the same antibiotics (Table 2). In addition, the nitrogen-fixing bacilli belonging to Bacillus polymyxa and B. macerans showed sensitivity to neomycin and kanamycin. Except for the species C. tyrobutyricum, none of the various saccharolytic Clostridium species could be distinguished by differences in sensitivity to antibiotics. Differential methods are given in Table 3.