Clinical and microbiological characteristics of severe Streptococcus pyogenes disease in Europe

Abstract

In an attempt to compare the epidemiology of severe Streptococcus pyogenes infection within Europe, prospective data were collected through the Strep-EURO program. Surveillance for severe cases of S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe by using a standardized case definition and questionnaire. Patient data as well as bacterial isolates were collected and characterized by T and M/emm typing, and selected strains were analyzed for the presence of superantigen genes. Data were analyzed to compare the clinical and microbiological patterns of the infections across the participating countries. A total of 4,353 isolates were collected from 5,521 cases with severe S. pyogenes infections who were identified. A wide diversity of M/emm types (n = 104) was found among the S. pyogenes clinical isolates, but the M/emm type distribution varied broadly between participating countries. The 10 most predominant M/emm types were M/emm type 1 (M/emm1), M/emm28, M/emm3, M/emm89, M/emm87, M/emm12, M/emm4, M/emm83, M/emm81, and M/emm5, in descending order. A correlation was found between some specific disease manifestations, the age of the patients, and the emm types. Although streptococcal toxic shock syndrome and necrotizing fasciitis were caused by a large number of types, they were particularly associated with M/emm1 and M/emm3. The emm types included in the 26-valent vaccine under development were generally well represented in the present material; 16 of the vaccine types accounted for 69% of isolates. The Strep-EURO collaborative program has contributed to enhancement of the knowledge of the spread of invasive disease caused by S. pyogenes within Europe and encourages future surveillance by the notification of cases and the characterization of strains, which are important for vaccination strategies and other health care issues.

FIG. 1.

emm type distribution among 10 of the countries participating in the Strep-EURO program in the years 2003 and 2004. The numbers of isolates from each country are indicated beneath each bar. (A) Distribution of the 10 most prevalent emm types within each country and overall, with and without the isolates from the United Kingdom. The overall 10 most prevalent types are indicated on the bar for the total, and other types present in each country are indicated. (B) Distribution of the overall 10 most prevalent emm types. The types present when the type made up more than 5% of all types within a country are indicated by the numbers in the figure. Country abbreviations: CZE, Czech Republic; DNK, Denmark; FIN, Finland; FRA, France; GER, Germany; GRC, Greece; ITA, Italy; ROU, Roumania; SWE; Sweden; UK, the United Kingdom.

FIG. 2.

Overall seasonal fluctuation in the overall 10 most prevalent emm types among the countries participating in the Strep-EURO program. Percentages are calculated from the number of each major type divided by the total number of isolates per month.

FIG. 3.

Distribution of emm types among invasive GAS cases the countries participating in the Strep-EURO program with special regard to coverage by a 26-valent candidate vaccine. Types hypothetically covered or not covered by the vaccine candidate are indicated. (A) Prevalence of the 30 most common emm types. Among these, 16 (accounting for 69% of the reported cases) are included in the 26-valent vaccine (since subtypes were not assessed, vaccine subtype emm1.2 is not considered in the present discussion). Vaccine types emm14, emm19, and emm114 were not encountered. Other 1, other types included in the vaccine (6 emm types); Other 2, remaining types not covered by the vaccine (70 different emm types). (B) Proportions of country-specific emm types determined on the basis of potential coverage by the 26-valent vaccine. The numbers of emm types potentially covered or not covered are indicated below the graph for each country. Country abbreviations: CZE, the Czech Republic; DNK, Denmark; FIN, Finland; FRA, France; GER, Germany; GRC, Greece; ITA, Italy; ROU, Romania; SWE; Sweden; UK, the United Kingdom.