The spot pyrrolidonyl arylamidase (PYR) test is commonly performed to separate Enterococcus species (positive reaction) from the Streptococcus bovis/Streptococcus equinus complex (SBSEC, formerly group D streptococci), which are negative.
It should be remembered that Streptococcus pyogenes (group A) also produces PYR; therefore, additional characteristics such as beta hemolysis are important. Some species of Aerococcus and Gemella are also PYR-positive; however, they can be suspected if large cocci in tetrads or clusters are observed on Gram stain. These species are rare isolates in most clinical practices.
