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Sequential colonization by Streptococcus pneumoniae of healthy children living in an orphanage
J Raymond1, I Le Thomas, F Moulin
1Service Microbiologie, Hôpital Saint Vincent de Paul, 75674 Paris Cedex 14, France. j.raymond@svp.ap-hop-paris.fr
Insights
Streptococcus pneumoniae colonization was high in young children in a closed community, with most isolates showing penicillin resistance. Limited clones rapidly spread, leading to frequent S. pneumoniae isolate turnover.
Area of Science:
- Pediatrics
- Microbiology
- Epidemiology
Background:
- Nasopharyngeal colonization by Streptococcus pneumoniae is a significant public health concern.
- Understanding colonization dynamics in vulnerable populations is crucial for intervention strategies.
Purpose of the Study:
- To investigate Streptococcus pneumoniae colonization patterns in young children (<24 months) within a closed community setting.
- To determine the prevalence, resistance, and clonal diversity of S. pneumoniae isolates.
Main Methods:
- A prospective, year-long study involving monthly nasopharyngeal sampling of 71 children.
- Isolation and identification of S. pneumoniae, antibiotic susceptibility testing (penicillin), serotyping, and molecular typing (pulsed-field gel electrophoresis).
Main Results:
- High colonization rate (81.7%) of S. pneumoniae observed.
- Over 94% of isolates exhibited penicillin resistance.
- Children carried a mean of 3 different S. pneumoniae isolates, with a mean carriage duration of 2.2 months per isolate.
- Colonization was dominated by a few S. pneumoniae clones across 4 serotypes and 4 pulsotypes, spreading rapidly in waves.
Conclusions:
- Young children in closed communities experience high rates of S. pneumoniae colonization with predominantly penicillin-resistant strains.
- Limited S. pneumoniae clones rapidly disseminate within this setting, leading to frequent acquisition and clearance of different isolates.
- Close community contact facilitates rapid transmission and turnover of S. pneumoniae strains.
Abstract:
A prospective study of nasopharyngeal colonization by Streptococcus pneumoniae in the exceptional conditions of a closed community of abandoned children was done over a 1-year period; 71 children (age <24 months) were studied monthly. S. pneumoniae was isolated from 58 (81.7%), and 94.5% of the 111 isolates were resistant to penicillin. The mean rate of carriage was estimated at 57.4%, ranging from 42.8% to 70.4%. Children were sequentially colonized by a mean of 3 different isolates. The mean duration of carriage for a given isolate was approximately 2.2 months. Serotyping and molecular typing by pulsed-field gel electrophoresis showed that children were colonized by a limited number of clones belonging to only 4 serotypes and 4 pulsotypes. These clones rapidly spread in the community and colonized the children in waves, with a rapid turnover of S. pneumoniae isolates, facilitated by close contact between children.