title: Association of serotype with respiratory presentations of pneumococcal infection, Ontario, Canada, 2003-2011.
abstract: BACKGROUND
  Pneumococcal disease burden is difficult to quantify due to limited data regarding non-bacteremic disease. We assessed serotype-specific differences in pneumococcal disease presentations in adults in Toronto, Canada.
  
  
  METHODS
  From 2003 to 2011, population-based surveillance for invasive pneumococcal disease was conducted and respiratory pneumococcal isolates collected in Metropolitan Toronto/Peel Region, Canada. Episodes of care were classified into disease categories.
  
  
  RESULTS
  Of 3105 eligible cases of IPD, 2060 cases were bacteremic pneumonia, and 1045 bacteremia without pneumonia. Of 2751 eligible respiratory cases, 1542 (56.0%) were non-bacteremic pneumonia (NBPP), 467 (17.0%) were other acute respiratory infection (oARI), and 742 (27.0%) were isolates representing colonization. Serotypes 3 (11.3%), 19A (8.4%) and 22F (6.2%) were the most common; serotypes 1,5, and 8 were rare. Serotypes 4, 14, 7F, 9V, 12F, 14, 19A and 6C were over-represented in bacteremic disease, and serotypes 3, 6A, 11A, 19F, 23A, 23F, 35B, 35F were more common in NBPP. The proportion of cases due to PCV7 serotypes declined from 48.7% to 8.7% in bacteremic pneumonia, from 35.3% to 10.9% in NBPP, from 34.2% to 7.5% in oARI, and from 38.7% to 12.2% in colonizing isolates. In 2010-2011, PCV13 serotypes accounted for 62.6% of isolates associated with bacteremic pneumonia, 42.0% of bacteremia without pneumonia, 41.1% of NBPP, 25.7% of oARI, and 32.9% of colonizing isolates.
  
  
  CONCLUSIONS
  Serotype distributions differ significantly in different presentations of pneumococcal disease. Herd protection due to PCV7 has changed serotype distribution, but PCV13 serotypes remain important in all categories of disease.
authors.affiliation: Mount Sinai Hospital, Toronto, Canada.
authors.forename: Altynay
authors.initials: A
authors.lastname: Shigayeva
authors.affiliation: Mount Sinai Hospital, Toronto, Canada; University of Toronto, Toronto, Canada.
authors.forename: Wallis
authors.initials: W
authors.lastname: Rudnick
authors.affiliation: Mount Sinai Hospital, Toronto, Canada.
authors.forename: Karen
authors.initials: K
authors.lastname: Green
authors.affiliation: Alberta Provincial Public Health Laboratory, Edmonton, Alberta, Canada.
authors.forename: Gregory
authors.initials: G
authors.lastname: Tyrrell
authors.affiliation: National Microbiology Laboratory, Winnipeg, Manitoba, Canada.
authors.forename: Walter H B
authors.initials: WH
authors.lastname: Demczuk
authors.affiliation: University of Toronto, Toronto, Canada; University Health Network, Toronto, Canada.
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Gold
authors.affiliation: University of Toronto, Toronto, Canada; Public Health Ontario, Toronto, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gubbay
authors.affiliation: University of Toronto, Toronto, Canada; Public Health Ontario, Toronto, Canada.
authors.forename: Frances
authors.initials: F
authors.lastname: Jamieson
authors.affiliation: Mount Sinai Hospital, Toronto, Canada.
authors.forename: Agron
authors.initials: A
authors.lastname: Plevneshi
authors.affiliation: Mount Sinai Hospital, Toronto, Canada.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Pong-Porter
authors.affiliation: University of Toronto, Toronto, Canada; Hospital for Sick Children, Toronto, Canada.
authors.forename: Susan
authors.initials: S
authors.lastname: Richardson
authors.affiliation: Mount Sinai Hospital, Toronto, Canada; University of Toronto, Toronto, Canada. Electronic address: amcgeer@mtsinai.on.ca.
authors.forename: Allison
authors.initials: A
authors.lastname: McGeer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000453:epidemiology*; D018410:Pneumonia, Bacterial / Q000453:epidemiology*; D011159:Population Surveillance; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000302:isolation & purification; D055815:Young Adult
keywords: Invasive pneumococcal disease; Pneumococcal vaccine; Pneumonia; Serotype