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Pneumococcal carriage amongst children in Adelaide, South Australia
Insights
Pneumococcal carriage in healthy children aged 6 months to 4.5 years was high, with 91% carrying the bacteria over five months. Common types included 6, 19, and 23, with low antimicrobial drug resistance observed.
Area of Science:
- Pediatric infectious diseases
- Microbiology
- Epidemiology
Background:
- Pneumococcal carriage is a significant factor in the transmission of Streptococcus pneumoniae.
- Understanding carriage rates and types in young children is crucial for public health strategies.
Purpose of the Study:
- To determine the prevalence and types of pneumococcal carriage in healthy children in Adelaide.
- To assess the frequency of carriage over time and identify common serotypes.
- To investigate the antimicrobial resistance patterns of carried pneumococcal strains.
Main Methods:
- A cross-sectional study involving 1267 children aged 6 months to 4.5 years.
- Monthly nasal swabs collected from 269 children over five occasions.
- Serotyping of pneumococcal isolates and antimicrobial susceptibility testing.
Main Results:
- A single-swab pneumococcal carriage rate of 29% was observed.
- 91% of children carried pneumococcus on at least one occasion over five months.
- Types 6, 19, and 23 were the most common serotypes, accounting for 57% of isolates.
- Antimicrobial resistance was low, with no dual or multiple drug resistance detected.
Conclusions:
- Pneumococcal carriage is highly prevalent in young children.
- Specific serotypes, some associated with invasive disease, dominate carriage.
- Low levels of antimicrobial resistance suggest current susceptibility to key antibiotics.
Abstract:
Amongst 1267 healthy children 6 months to 4.5 years of age in Adelaide, the pneumococcal carriage rate from a single nasal swab sampling was 29% in the period 1980-1. Of 269 children, sampled monthly on five occasions, 91% carried a pneumococcus on one or more occasions: 55% carried a single type, 33% carried two types, 2% carried three types and 1% carried four types; 18% carried a pneumococcus on either 4 or 5 occasions. The commonest types encountered were types 6, 19 and 23 in that order, and these three types constituted 57% of the total: other common types (greater than 5% of the total) were types 14, 15 and 11, and the six commonest types constituted 77% of the total. Of these, types 6, 14, 19 and 23 commonly cause systemic disease in children; on the other hand types 11 and 15 cause disease infrequently. The number of strains showing antimicrobial drug resistance was low: on quantitative testing 0.7% of 291 isolates examined showed relative resistance to benzylpenicillin and 0.7% were resistant to tetracycline; 10.9% of 230 isolates examined showed resistance to co-trimoxazole; dual or multiple drug resistance was not detected, and all isolates tested were susceptible to chloramphenicol, erythromycin, lincomycin and rifampicin.