Isolation from soils ofNitrobacter and evidence for novel serotypes using immunofluorescence

To study the ecology of chemoautotrophic nitrifying bacteria (Nitrobacter), the immunofluorescence technique has been used. Fluorescent antibodies againstNitrobacter winogradskyi andNitrobacter agilis, the two known serotypes, have not labeled strains isolated from soils of the Lyon region (pH 8.1 and pH 4.7). The pure-culture isolates appeared to belong to the same genus, but to be serologically different from the reference strains. These results led us to question the diversity of strains ofNitrobacter in soils.