Clinical and epidemiologic features of group A streptococcal pneumonia in Ontario, Canada

Matthew P. Muller, Donald E. Low, Karen A. Green, Andrew E. Simor, Mark Loeb, Daniel Gregson, Allison McGeer, H. Dele Davies, Michael John, Raphael Saginur, Peter Jessamine, James Talbot, Marguerite Lovgren, Barbara Mederski, Alicia Sarabia, Liljana Trpeski, Barbara Willey, Agron Plevneshi, Margaret McArthur, Sharon Walmsley

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


Background: Since the 1960s, group A streptococcus (GAS) has accounted for less than 1% of cases of community-acquired pneumonia. During the past 2 decades there has been a resurgence of invasive GAS infection, but no large study of GAS pneumonia has been performed. Methods: To determine the clinical and epidemiologic features of GAS pneumonia, we conducted prospective, population-based surveillance of all invasive GAS infection in residents of Ontario from January 1, 1992, through December 31, 1999. Results: Of 2079 cases of invasive GAS infection, 222 (11%) represented GAS pneumonia. The incidence of GAS pneumonia ranged from 0.16 per 100 000 in 1992 to 0.35 per 100 000 in 1999. Most cases were community acquired (81%). Forty-four percent of nursing home-acquired cases occurred during outbreaks. The case fatality rate was 38% for GAS pneumonia, compared with 12% for the entire cohort with invasive GAS infection and 26% for patients with necrotizing fasciitis. The presence of streptococcal toxic shock syndrome (odds ratio, 19; 95% confidence interval, 8.4-42; P=.001) and increasing age (odds ratio per decade, 1.45; 95% confidence interval, 1.2-1.7; P <.001) were associated with fatal outcome. Time to death was rapid, with a median of 2 days despite antimicrobial therapy and supportive measures. Conclusions: Group A streptococcal pneumonia is a common form of invasive GAS disease but remains an uncommon cause of community-acquired pneumonia. Progression is rapid despite appropriate therapy. The incidence is similar to, and the case fatality rate higher than, that of necrotizing fasciitis.

Original languageEnglish (US)
Pages (from-to)467-472
Number of pages6
JournalArchives of Internal Medicine
Issue number4
StatePublished - Feb 24 2003
Externally publishedYes

ASJC Scopus subject areas

  • Internal Medicine


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