Low rate of pneumococci non-susceptible to penicillin in healthy Swedish toddlers

Abstract

Background: Infection caused by Streptococcus pneumoniae is the leading cause of mortality in children worldwide. The aim of this study was to determine if a noted increase in non-susceptibility to penicillin among pneumococcal clinical isolates from young children reflected a similar increase in healthy children. Methods: During 2004–2005, before the conjugate pneumococcal vaccine was introduced in Sweden, 663 healthy children (13–24 months of age) attending 17 child health centres in Gothenburg, Sweden, were cultured for bacteria in the nasopharynx. Social factors were identified through a parental questionnaire. Pneumococcal serotypes and antibiotic resistance rates were determined. Antibiotic resistance was also monitored in 162 simultaneously obtained nasopharyngeal pneumococci isolated from clinical samples. Results: The healthy children frequently carried pneumococci (45%), Moraxella catarrhalis (54%), and Haemophilus influenzae (22%). The carriage rates for all these pathogens were higher in children attending day care centres compared to children staying at home (p < 0.001). The dominating pneumococcal serotypes were 6B, 19F, 23F, and 6A. Non-susceptibility to penicillin was low (4.0%) and only exceeded by that to trimethoprim–sulfamethoxazole (9.8%). Both rates were higher in the clinical isolates (9.3% and 16.7%, respectively; p < 0.05). No relationships to geographic area, day care attendance, recent antibiotic use, or travel abroad were shown for any specific serotype or for the presence of penicillin-non-susceptible pneumococci in the healthy children. Conclusions: Pneumococcal resistance rates in the healthy child population were low and did not reflect the higher rates noted at the laboratory in clinical samples obtained before and during the study.

Keywords::

• Pneumococci
• Streptococcus pneumoniae
• nasopharynx
• healthy children
• antibiotic resistance

Acknowledgements

We thank Eva Person and the nurses in the participating Child Health Centres in Gothenburg for recruiting and sampling the children in the study. We also thank Margaretha Antonsson and colleagues of the Bacteriology Laboratory at Sahlgrenska University Hospital, Gothenburg, and co-workers at the Swedish Institute for Communicable Disease Control, for technical assistance.

Declaration of interest: The study was supported by Strama (The Swedish Strategic Programme Against Antibiotic Resistance). There are no commercial relationships or potential conflict of interests.