title: Reduced susceptibility to penicillin among pneumococci causing invasive infection in children - Canada, 1991 to 1998.
abstract: OBJECTIVE
  To determine, over time, the rate and serotypes of pneumococci with reduced penicillin susceptibility obtained from children with invasive infection.
  
  
  METHODS
  Active, hospital-based, multicentre surveillance spanning from 1991 to 1998.
  
  
  METHODS
  Eleven Canadian tertiary care paediatric facilities located from coast to coast.
  
  
  METHODS
  1847 children with invasive pneumococcal infection whose isolates (from a normally sterile site) were available for serotyping and standardized testing for penicillin susceptibility at the National Centre for Streptococcus.
  
  
  RESULTS
  The prevalence of reduced penicillin susceptibility increased from 2.5% of 197 cases in 1991 to 13.0% of 276 cases in 1998. In the latter year, 8.7% of isolates had intermediate level resistance, and 4.3% had high level resistance. Since they were first detected in 1992, strains with high level resistance have been encountered only sporadically at most centres, but by 1998, all centres but two had encountered examples. Of 40 isolates with high level resistance and 101 isolates with intermediate level resistance, serotypes matched those included in new seven-valent conjugate vaccines for children in 97.5% and 79.2% of cases, respectively.
  
  
  CONCLUSIONS
  Pneumococci with reduced susceptibility to penicillin are increasing in frequency across Canada among children with invasive infection. The Immunization Monitoring Program, Active data indicate that new conjugate vaccines could help to curb infections due to pneumococci with reduced susceptibility to penicillin but are unlikely to control completely the problem of antibiotic resistance.
authors.affiliation: Canadian Paediatric Society/Laboratory Centre for Disease Control Immunization Monitoring Program, Active (IMPACT), Ottawa, Ontario;
authors.forename: D
authors.initials: D
authors.lastname: Scheifele
authors.forename: S
authors.initials: S
authors.lastname: Halperin
authors.forename: L
authors.initials: L
authors.lastname: Pelletier
authors.forename: J
authors.initials: J
authors.lastname: Talbot
authors.forename: M
authors.initials: M
authors.lastname: Lovgren
authors.forename: W
authors.initials: W
authors.lastname: Vaudry
authors.forename: T
authors.initials: T
authors.lastname: Jadavji
authors.forename: B
authors.initials: B
authors.lastname: Law
authors.forename: N
authors.initials: N
authors.lastname: Macdonald
authors.forename: R
authors.initials: R
authors.lastname: Gold
authors.forename: E
authors.initials: E
authors.lastname: Wang
authors.forename: E
authors.initials: E
authors.lastname: Mills
authors.forename: M
authors.initials: M
authors.lastname: Lebel
authors.forename: P
authors.initials: P
authors.lastname: Déry
authors.forename: R
authors.initials: R
authors.lastname: Morris