[Serologic diagnosis of streptococcal diseases. Ulterior data on the comparison of 2 methods (streptozyme and antistreptolysin O].
Increasingly thorough analysis of the antigen structures of Group A beta-haemolytic streptococci has revealed the presence of antigen components with differentiated immune responses in relation to common streptococcal conditions. It is therefore extremely useful in laboratory practice to have a multiple antigen that reveals the immune response to a streptococcal infection so that we can study the serological behaviour of individual streptococcal pictures with their complications and sequelae. Research conducted to date indicates that the streptozyme test can explore the five main streptococcal isoenzymes both for rapid screening and for the quantification of the degree of antibody response. This is confirmed by the results obtained by numerous Authors over the past 15 years, results that demonstrate the high sensitivity of STZ (Streptozyme) at antibody level that single antibody reactions are apparently not capable of revealing. The polyvalent antigen represented by STZ seems to be the best tool for the demonstration of responses to the individual isoenzymes of the very numerous streptococcal strains in circulation (Group A, C and G beta-haemolytics). The possibility of using microtiter techniques for serum assays is also emphasised. These techniques have given repeatable results and are also easy to read.