In this sense, although the gyrB or rpoB genes appeared to be good candidates for Bacillus species differentiation, little conserved regions were found, this difficulting the design of primers for their universal amplification. In contrast, the tuf gene exhibited enough conserved regions for primer design and enough variable regions for species-specific identification, either by coupling sequencing or restriction fragment length polymorphism analysis. These results agree with previous studies that pointed out the tuf gene as a good candidate for inferring relationships among closely related species other than Bacillus spp.