[Determination of biovars of Brucella melitensis by manometric character: epidemiological value and relation to...

As Brucella melitensis is the most frequently encountered Brucella species in human medicine, and as its subdivision into three serovars is insufficient for epidemiological studies, we sought to define a new scheme for biotyping of this species. For this purpose, we studied 94 strains for their oxidative metabolic rates on 32 substrates and their susceptibility to ten antibiotics, and 132 strains for their activities with three enzymes. A taxonomic study on the basis of the 32 oxidative metabolic rates led to the distinction of five biovars which could then be defined by means of the five most discriminating substrates. Among the ten antibiotics tested, only three showed varying patterns of susceptibility. Oxidative metabolic rates were not correlated with these patterns of susceptibility nor with the enzymatic activities. However, a relationship was found between biovar and serovar, especially with regard to the following substrates: meso-erythritol, deoxythymidine, D-galactose and DL-phenylalanine. As shown by correspondence analysis, the repartition of biovars significantly differed among French administrative regions.