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Reduced susceptibility to penicillin among pneumococci causing invasive infection in children - Canada, 1991 to 1998
D Scheifele1, S Halperin, L Pelletier
1Canadian Paediatric Society/Laboratory Centre for Disease Control Immunization Monitoring Program, Active (IMPACT), Ottawa, Ontario;
Insights
Penicillin-resistant pneumococci are rising in Canadian children with invasive infections. While new conjugate vaccines may help, they won't fully resolve antibiotic resistance issues.
Area of Science:
- Pediatric Infectious Diseases
- Antimicrobial Resistance
- Vaccinology
Background:
- Invasive pneumococcal infections pose a significant threat to children.
- Monitoring antimicrobial resistance patterns is crucial for public health.
- Penicillin resistance in Streptococcus pneumoniae has emerged as a growing concern.
Purpose of the Study:
- To track the incidence and serotypes of penicillin-nonsusceptible pneumococci in children with invasive infections.
- To evaluate the changing trends of reduced penicillin susceptibility over time.
Main Methods:
- Conducted active, hospital-based, multicenter surveillance across 11 Canadian tertiary care pediatric facilities.
- Collected and analyzed 1847 isolates from children with invasive pneumococcal infections between 1991 and 1998.
- Performed standardized testing for penicillin susceptibility and serotyping.
Main Results:
- Prevalence of reduced penicillin susceptibility increased from 2.5% in 1991 to 13.0% in 1998.
- In 1998, 8.7% of isolates showed intermediate resistance and 4.3% showed high-level resistance.
- Serotypes covered by new heptavalent conjugate vaccines accounted for 97.5% of high-level and 79.2% of intermediate-level resistant isolates.
Conclusions:
- Penicillin-nonsusceptible pneumococci are increasingly frequent in Canadian children with invasive infections.
- New conjugate vaccines show promise in reducing infections caused by resistant strains.
- These vaccines are unlikely to completely eliminate the challenge of antibiotic resistance.
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.
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