Results obtained in the first year of active surveillance of serious diseases caused by group A streptococci in the Czech Republic carried out within the Strep-EURO project are summarized. From January to December 2003, 28 Czech laboratories referred to the National Institute of Public Health 59 group A streptococcal strains isolated from invasive diseases meeting the Strep-EURO definition. At the same time, clinical-epidemiological data and information on the catchment area population were provided. For 2003, the total morbidity and case fatality rates were calculated to be 1.3/100 000 population and 13.5 %, respectively. A high proportion (23.7 %) of the 59 strains were of type emm 1, initially labeled M1. As many as 24.1 %, 17.2 % and 20.7 % of the strains tested were resistant to erythromycin, clindamycin and tetracycline, respectively. The seemingly lower morbidity rate and higher case fatality rate from serious diseases caused by group A streptococci reported in the Czech Republic for 1994–1996, i.e. 0.4/100 000 and 46.5 %, respectively, in comparison with the latest data can be explained by the use of softer international criteria for the Strep-EURO definition of invasive disease.

        Key words: emm typing – invasive GAS – resistance – streptococcus – surveillance.