Epidemiology, outcome and emm types of invasive group A streptococcal infections in Finland.
In 2006, Finnish nationwide surveillance showed an increase of invasive group A streptococcal (iGAS) disease and clinicians were alarmed by severe disease manifestations, prompting the investigation of recent trends and outcome for iGAS. A case of iGAS was defined as Streptococcus pyogenes isolated from blood or cerebrospinal fluid. Cases during 1998-2007 and isolates during 2004-2007 were included. Case-patients' 7-day outcome was available for 2004-2007. Isolates were emm typed. A total of 1,318 cases of iGAS were identified. The average annual incidence was 2.5/100,000 population. The rate was higher in males than females in persons aged 45-64 years, but lower in persons aged 25-34 years. The annual incidence was highest in 2007 (3.9/100,000). Occasional peaks occurred during midwinter and midsummer. The most common emm types were 28 (21%), 1 (16%), 84 (10%), 75 (7%) and 89 (6%). During 2004-2007, emm1 replaced emm28 as the most predominant type. The overall case fatality was 8%. Cases with emm1 were associated with high case fatality (14% vs. 8% in other types; p < 0.02); that of emm28 infections was 2% (p < 0.01). Changes in emm type prevalence influenced incidence and case fatality. Differences in age- and sex-specific incidence and seasonal patterns suggest variations in predisposing factors and underlying conditions.
Siljander
T
T
Bacteriology Unit, Department of Infectious Disease Surveillance and Control, National Institute for Health and Welfare, P.O. Box 30, 00271 Helsinki, Finland. tuula.siljander@thl.fi
Lyytikäinen
O
O
Vähäkuopus
S
S
Snellman
M
M
Jalava
J
J
Vuopio
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000235:genetics*; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D015373:Bacterial Typing Techniques; D001769:Blood / Q000382:microbiology; D002352:Carrier Proteins / Q000235:genetics*; D002555:Cerebrospinal Fluid / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005387:Finland / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016920:Meningitis, Bacterial / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D008875:Middle Aged; D012307:Risk Factors; D012621:Seasons; D017678:Sex Distribution; D013290:Streptococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000302:isolation & purification*; D016896:Treatment Outcome; D055815:Young Adult
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein