Table 1.

Nitroreductase activity in cultures and cell-free supernatants of parental strains and nitrofurantoin-resistant mutants of Clostridium spp.

StrainNitroreductase activity fora:
CellsSoluble protein
Parental strainResistant strainParental strainResistant strain
Clostridium perfringens ATCC 362689.5102.66.810.4
Clostridium paraputrificum NR139.8135.41.12.8
Clostridium sp. strain NR874.7102.32.73.3
Clostridium sp. strain NR9156.1227.03.33.9
Clostridium leptumNP15NDND5.421.8
  • a Results are expressed as units of activity where a unit is the amount of enzyme that produces 1 μg of 4-aminobenzoic acid per h from 4-nitrobenzoic acid at 37°C: for cells, units of activity per cell absorbance (A 600); for protein, units of activity per milligram of soluble protein. ND, not determined.