Nasopharyngeal colonization by potentially pathogenic bacteria found in healthy children from an elementary school

[摘要] INTRODUCTION: human nasopharynx is a natural reservoir of potentially pathogenic bacteria which are important etiological agents of common infections that affect all age groups, particularly the child population.OBJECTIVE: finding out the prevelance of these potential pathogens in healthy children.METHODS: Taking into account the bioethical requirement set for these kind of study in 2002, a descriptive cross-sectional study of carriers was performed on 318 pupils from an elementary school in Havana. Samples from their pharynx were taken for testing and their parents answered a questionnaire on the risk factors affecting the condition of the carrier (age, sex, crowding, passive smoking, history of infectious or allergic respiratory disease). The sample was taken at the school, then the smear was directly placed in the culture media and the isolated bacteria were identified by conventional methods and by the API NH system.RESULTS: the percentage of potentially pathogenic bacteria carriers was high (55 %) in which Staphylococcus aureus (33.6 %), hemolytic streptococci b (17.3 %) y Streptococcus pneumoniae (11.6 %). Among the hemolytic streptococci b, the group G (49 %) predominated, followed by A and C with 18.2 % of carriers in each group. Age was a significant risk factor (p< 0.05), being the highest percentages of carriers in children aged 10 (60 %), 11 (75.5 %) and 12 (77.3 %) years. There was statistically significant relation between meningococcal carriers and crowding (p= 0.043). The association of S. aureus plus hemolytic streptococci b (27.9 %) predominated, mainly in allergic children (p< 0.05). Neisseria lactamica was isolated in 29.6 % and prevented the colonization by N. meningitidis (p= 0.0004).CONCLUSIONS: this research study made it possible to identify the patterns of nasopharyngeal colonization by potentially pathogenic bacteria in healthy children and their association with the studied risk factors.

[学科分类] 传染病学

[关键词] : Asymptomatic carriers;potentially pathogenic bacteria;nasopharyngeal colonization;risk factors;allergic respiratory diseases