Use of enzymes in typing group A β-haemolytic streptococci Brahmadathan, K. N. and Koshi, Grace,, 27, 141-144 (1988), doi = https://doi.org/10.1099/00222615-27-2-141, publicationName = Microbiology Society, issn = 0022-2615, abstract= Summary A series of 698 strains of group A β-haemolytic streptococci (GAS) isolated from cildren with streptococcal pyoderma was tested for production of serum opacity factor (OF)and nicotinamide adenine dinucleotide glycohydrolase (NADase). OF was produced by 37% of strains and 40% produced NADase. Classification based on various combinations of OF and NADase reactions showed that 58% belonged to enzyme group e1 and 34% to e2. Correlation with T and M types showed the possible use of this means of classification as an epidemiological marker for GAS. The specificity of such a system in the further classification of various T types of GAS in epidemiological studies, in the light of antigenic variation among M types, is described., language=, type=