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Canadian Journal of Infectious Diseases
Volume 12, Issue 4, Pages 241-246
Original Article

Reduced Susceptibility to Penicillin among Pneumococci Causing Invasive Infection in Children - Canada, 1991-1998

David Scheifele,1 Scott Halperin,1 Louise Pelletier,2 James Talbot,3 Marguerite Lovgren,3 Wendy Vaudry,1 Taj Jadavji,1 Barbara Law,1 Noni MacDonald,1 Ron Gold,1 Elaine Wang,1 Elaine Mills,1 Marc Lebel,1 Pierre Déry,1 and Rob Morris1

1Canadian Paediatric Society/Laboratory Centre for Disease Control Immunization Monitoring Program, Active (IMPACT), Ottawa, Ontario, Canada
2Laboratory Centre for Disease Control, Ottawa, Ontario, Canada
3National Centre for Streptococcus, Edmonton, Alberta, Canada

Received 4 April 2000; Accepted 5 July 2000

Copyright © 2001 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


OBJECTIVE: To determine, over time, the rate and serotypes of pneumococci with reduced penicillin susceptibility obtained from children with invasive infection.

DESIGN: Active, hospital-based, multicentre surveillance spanning from 1991 to 1998.

SETTING: Eleven Canadian tertiary care paediatric facilities located from coast to coast.

POPULATION STUDIED: 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.

MAIN 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.