Pneumococcal Carriage in Children in The Netherlands: a Molecular Epidemiological Study

Abstract

In 1999, Engelen and coworkers investigated colonization in Amsterdam among 259 children attending 16 day-care centers (DCCs) and among 276 children who did not attend day-care centers (NDCCs). A 1.6-to 3.4-fold increased risk for nasopharyngeal colonization was observed in children attending DCCs compared with NDCC children, while no difference in antibiotic resistance was found between groups. The serotype and genotype distributions of 305 nasopharyngeal Streptococcus pneumoniae isolates of the latter study were investigated. The predominant serotypes in both the DCC and the NDCC groups included 19F (19 and 18%, respectively), 6B (14 and 16%, respectively), 6A (13 and 7%, respectively), 23F (9 and 7%, respectively), and 9V (7 and 7%, respectively). The theoretical vaccine coverage of the 7-valent conjugate vaccine was 59% for the DCC children and 56% for the NDCC group. Genetic analysis of the pneumococcal isolates revealed 75% clustering among pneumococci isolated from DCC attendees versus 50% among the NDCC children. The average pneumococcal cluster size in the DCC group was 3.8 and 4.6 isolates for two respective sample dates (range, 2 to 13 isolates per cluster), while the average cluster size for the NDCC group was 3.0 (range, 2 to 6 isolates per cluster). Similar to observations made in other countries, these results indicate a higher risk for horizontal spread of pneumococci in Dutch DCCs than in the general population. This study emphasizes the importance of molecular epidemiological monitoring before, during, and after implementation of pneumococcal conjugate vaccination in national vaccination programs for children.

Molecular Epidemiology of Pneumococcal Colonization in Response to Pneumococcal Conjugate Vaccination in Children with Recurrent Acute Otitis Media

“…Susceptibility testing of 919 of the 921 pneumococcal isolates was performed for penicillin, cotrimoxazole, tetracycline, erythromycin, rifampin, vancomycin, cefotaxime, and ciprofloxacin. In agreement with previous studies performed in The Netherlands, the overall resistance is low (14% of the isolates) compared to that found in other European countries (4,13,14,17,18). Penicillin resistance was found rarely in our study.…”

Variation in Streptococcus pneumoniae susceptibility to human antimicrobial peptides may mediate intraspecific competition

“…(a) Strains and media Carriage isolates used in this study were isolated from the nasopharynx of healthy children attending several day-care centres in the Netherlands and have been described previously [26]. Clinical isolates were provided by the Centers for Disease Control (CDC) and the University of Liverpool.…”

Molecular Epidemiology of Pneumococcal Carriage among Children with Upper Respiratory Tract Infections in Hanoi, Vietnam

“…Pneumococci are often part of the nasopharyngeal flora; especially due to circumstances of crowding, as observed in day-care centers, nursing homes, and hospitals, the risk of being colonized with pneumococci is increased (3,20,27,28). Usually, colonization is not followed by disease, as local barriers at the mucosal level of the respiratory tract and the human immune system are often protective.…”