Lectins for the identification of ocular bacterial pathogens

In a preliminary in vitro investigation, fluorescein-conjugated lectins were used in the identification of bacteria commonly involved in ocular infections. Clinical isolates of Staphylococcus aureus, Staph. epidermidis, Streptococcus pneumoniae, Strep. pyogenes, Pseudomonas aeruginosa, Hemophilus influenzae, and Proteus mirabilis were incubated with each of eleven lectins using a slide technique. Bacterial fluorescence was readily observed with a fluorescence microscope. All clinical isolates bound wheat germ agglutinin. The Gram-positive isolates bound Concanavalin A, while the Gram-negative isolates did not, with rare exceptions. Streptococcal species isolates reacted with Dolichos biflorus agglutinin, while staphylococcal species isolates did not. Lectins may be useful in furthering the initial identification of causative organisms in bacterial ocular infections.