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Lancet. 2001 Oct 20;358(9290):1334-7.

Dynamic epidemiology of group A streptococcal serotypes associated with pharyngitis.

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Department of Pediatrics, WHO Collaborating Center for Reference and Research on Streptococci, University of Minnesota Medical School, Minneapolis, MN 55455, USA.



Despite the past 15 years of heightened awareness of the disease-causing potential of group A streptococci, the possible epidemiological influence of rapid changes in prevalent serotypes has not been fully appreciated.


We analysed throat cultures collected as part of routine medical care in a semi-closed community of nearly 500 children and adults between January, 1999, and April, 2000. beta-haemolytic streptococci from all positive cultures were characterised by serological grouping, T-agglutination pattern, and serotyping for M protein or opacity factor.


We saw an increase in the number of symptomatic individuals with pharyngitis beginning in mid-1999. Between July 1 and Dec 31, 1999, 111 (29%) of 378 throat cultures yielded group A streptococci, 102 (92%) of which were serotype M1. Between Jan 1 and Mar 31, 2000, 126 (45%) of 277 throat cultures yielded group A streptococci. Unexpectedly, 106 (84%) of these throat isolates were serotype M6, and only 16 (13%) were M1. 20 (28%) of the 71 individuals with M1 infection subsequently acquired infection with M6.


This rapid and almost complete shift in predominance of group A streptococcal serotype in this community draws attention to the dynamic epidemiology of these organisms. This change has important implications for further understanding the epidemiology of group A streptococcal infections, and for the development and use of a vaccine.

[Indexed for MEDLINE]

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