Rapid identification of Mycobacterium species by lectin agglutination

The purpose of the present study is to explore the possibility that plant lectins can be used for the development of rapid and inexpensive technique for differentiation of mycobacterial species. The method is based on interaction between mycobacteria and lectins as visualized by agglutination in a microtiter plate. We employed 18 mycobacterium species and determined the minimal lectin concentration (MLC) of 23 different lectins. For some of the bacteria as a high as 1000 μg/ml of one or more lectins were required to induce agglutination, while for other strains as low as 1.95 μg/ml of the lectin were needed. A unique pattern of agglutination was observed for each species over a range of 62–1000 μg/ml lectin concentrations. There were little or no variations in MLC within strains (intraspecies) of each of two species tested. In contrast, there were marked interspecies variations in MLC. Analysis of the MLC showed that the highest score of interspecies differences with 23 lectins was obtained at 125 μg/ml lectin concentration. At this concentration it was found that the pattern of agglutinations with only two lectins was sufficient to differentiate mycobacterium species from each other. Because the bacteria–lectin interaction is adaptable to various methods of visualization, our findings may set the stage for developing a rapid and reliable tool to differentiate mycobacterium species.