The NAD-glycohydrolase (nga) gene of Streptococcus pyogenes

The gene for NAD-glycohydrolase (nga) of group A streptococci (Streptococcu s pyogenes) was identified and shown to be located immediately adjacent to the gene for streptolysin O (slo). The nga gene contains 1341 base pairs an d encodes a protein of 447 amino acids, including an N-terminal signal pept ide. Results from analysis with the polymerase chain reaction indicated tha t the nga gene is present in all of the strains tested. Functional extracel lular NAD-glycohydrolase, also known as NADase, was detected among a wide v ariety of clinical isolates and known laboratory strains and shown to be pr esent in 72% of 100 strains examined. In contrast, 92% of strains isolated from patients with invasive streptococcal infections were positive for NADa se production. (C) 2000 Federation of European Microbiological Societies. P ublished by Elsevier Science B.V. All rights reserved.