Chondroitin sulfate depolymerase and hyaluronidase activities of viridans streptococci determined by a sensitive spectrophotometric assay

Sensitive spectrophotometric assays for the detection of bacterial chondroitin sulfate depolymerase and hyaluronidase activities were developed by using Stains-all (1-ethyl-2-[3-(1-ethylnaphtho-[1,2-d]thiazolin-2-ylidene)-2- methylpropenyl]naphtho-[1,2-d]thiazolium bromide). Stains-all interacts with hyaluronic acid to produce a shift in the absorption spectrum with a distinct absorption peak between 620 and 660 nm, while chondroitin sulfate interacts to form a distinct shoulder between 440 and 500 nm. Assays measure undegraded substrate. A collection of 110 strains of viridans streptococci, including representatives of all the currently recognized species, was studied. Streptococcus intermedius and S. constellatus degraded hyaluronic acid, while only strains of S. intermedius, primarily isolated from brain and liver abscesses, produced chondroitin sulfate depolymerase. S. intermedius, of all the viridans streptococci, produces the widest range of glycoprotein- and glycosoaminoglycan-degrading enzymes, which may contribute to the virulence of this species.