Biofilm formation by Borrelia sensu lato

Bacterial biofilms are microbial communities held together by an extracellular polymeric substance matrix predominantly composed of polysaccharides, proteins and nucleic acids. We had previously shown that Borrelia burgdorferi sensu stricto , the causative organism of Lyme disease in the United States is capable of forming biofilms in vitro . Here, we investigated biofilm formation by Borrelia afzelii and Borrelia garinii , which cause Lyme disease in Europe. Using various histochemistry and microscopy techniques, we show that Borrelia afzelii and Borrelia garinii form biofilms, which resemble biofilms formed by Borrelia burgdorferi sensu stricto . High-resolution atomic force microscopy revealed similarities in the ultra-structural organization of the biofilms form by three Borrelia species. Histochemical experiments revealed a heterogeneous organization of exopolysaccharides among the three Borrelia species. These results suggest that biofilm formation might be a common trait of Borrelia genera physiology.