Risk factors for nasopharyngeal carriage of Streptococcus pneumoniae and effects of a hygiene intervention: repeated cross-sectional cohort study at day care centres.

BACKGROUND: Day care attendance and antibiotic consumption are major risk factors for carriage of antibiotic-susceptible and non-susceptible pneumococci. We describe the nasopharyngeal carriage of antibiotic-susceptible and non-susceptible pneumococci among children at day care centres (DCCs), analyse the association of potential risk factors with carriage, and examine the effects of a hygiene intervention on carriage. METHODS: Thirty DCCs in 2 communities were included in a cohort intervention trial. Nasopharyngeal cultures and information on the children were obtained every 6 months. The study lasted 2.5 y and the hygiene intervention was introduced at half of the DCCs during the last 1.5 y of the study. The results were analysed using a mixed effects logistic regression model. RESULTS: A total of 5663 cultures were obtained from 2399 children, of which 55.6% grew pneumococci. Of the pneumococci, 27.9% were penicillin-non-susceptible (PNSP). The hygiene intervention was associated with a decreased risk of pneumococcal carriage, but this did not reach statistical significance for PNSP carriage. Pneumococcal and PNSP carriage was negatively associated with age, varied significantly between DCCs, and was positively associated with the number of preceding colds. Individual antibiotic use (mainly penicillin/amoxicillin) at the time of sampling and/or during the preceding month was associated with a decreased risk of pneumococcal and PNSP carriage. Individual use of cephalosporins was associated with an increased risk of carriage of penicillin and TMP-SMX-non-susceptible pneumococci. CONCLUSION: The hygiene intervention at the DCCs reduced the risk of pneumococcal carriage and the individual use of antibiotics was found to affect carriage in a complex manner.

Does hygiene intervention at day care centres reduce infectious illnesses in children? An intervention cohort study.

BACKGROUND: Day care attendance is a major risk factor for respiratory and gastrointestinal illnesses in preschool children. In this study, we describe the results of a hygiene intervention cohort trial at day care centres (DCCs) on the rates of febrile, respiratory, and gastrointestinal illnesses in preschool children. METHODS: Thirty DCCs in 2 communities were included. The number of illness episodes was registered for each child every 6 months, as well as potential risk factors. The hygiene intervention was introduced in half of the DCCs and the results analysed using a multivariate mixed effects hierarchical Poisson regression model. RESULTS: The study lasted 2.5 y, of which the hygiene intervention lasted 1.5 y. Two thousand three hundred and forty-nine children participated, delivering 2832 person-y. Adjusted incidence rate ratios of the illnesses at the intervention and non-intervention DCCs were not significantly different for any of the illnesses. The intervention was not more effective in children less than 3 y of age than in older children and no significant effects were seen with time. Compliance with the hygiene protocol was good as measured by the use of hygiene products and by a survey among the staff at the DCCs. CONCLUSIONS: The most likely explanation for the lack of effects of the intervention is that the baseline standard of hygiene at the DCCs was probably too high for the intervention to demonstrate significant results, but recall bias cannot be excluded. Even though hygiene is important for minimizing the spread of microbes at DCCs, other risk factors need to be studied.

Can risk factors for infectious illnesses in children at day care centres be identified?

BACKGROUND: The risk factors for febrile, respiratory, and gastrointestinal illnesses in preschool children at day care centres have not been adequately identified and may differ between countries. METHODS: In this repeated cross-sectional and longitudinal study of children at day care centres, we analyzed various potential risk factors for infectious illnesses using a mixed effect hierarchical Poisson regression model. The results of the analyses and the incidence rates of these illnesses are reported herein. RESULTS: The study lasted 2.5 y (2000-2003) and was divided into five 6-month periods (seasons). Nine hundred and seventeen children participated, and their mean age within each season was 3.6-4.1 y. The only consistent risk factors identified were young age and winter season. No consistent risk factors at the day care centres (facilities or hygiene practices) were identified. The incidences of the febrile, respiratory, and gastrointestinal illnesses varied significantly between seasons (winter/summer) and between age groups. CONCLUSIONS: Risk factors of infectious illnesses are difficult to identify and because they may vary between countries, international recommendations on expensive intervention strategies are not justifiable. Rates of respiratory illnesses in Icelandic preschool children appear higher than in other countries, but rates of gastrointestinal illnesses lower.