Epidemiological observations on Streptococcus pyogenes serotype T1 in Uppsala county, Sweden 1989-1995.

During the period 1989-1995, the T-type distribution pattern of Streptococcus pyogenes pharyngeal isolates was compared with the annual incidence of culture-verified S. pyogenes bacteremias in Uppsala county, Sweden. An exceptional increase in the number of S. pyogenes bacteremias was seen in 1994. During the study period, the annual number of blood culture isolates was shown to correlate with the proportion of S. pyogenes serotype T1 among pharyngeal isolates.