The specific recognition of host epithelial surfaces by pathogen receptors is often the first step of infection. Bacterial carbohydrate-binding proteins, called adhesins or lectins, specifically recognize glycoconjugates on host tissues. Opportunistic pathogens responsible for lung infections, such as some Pseudomonas and Burkholderia species, produce soluble lectins that bind to human fucosylated oligosaccharides. Among these targets, the observed variations in ABO and Lewis histo-blood group phenotypes are proposed to be a result of co-evolution between pathogens and mammals. The analysis of the available crystal structures of bacterial lectins helps deciphering the structure/function relationship involving this important class of protein. The high affinity observed between bacterial lectins and fucosylated oligosaccharides can be reached by different strategies in term of structures and thermodynamics. Structure-based design of glycomimetics and glycodendrimers resulted in very high affinity ligands that open the route towards novel anti-infectious strategies.