[Seroprevalence of Mycoplasma pneumoniae in children aged under 12 years].

INTRODUCTION Although Mycoplasma pneumoniae is usually assumed as an infection mainly prevalent in school aged children and adolescents, there is evidence supporting that it may occur at younger ages. This could be related to social conditions, like crowding and day care center/school attendance more frequently and at younger ages than two decades ago. We estimated the prevalence of antibodies anti- Mycoplasma pneumoniae in children aged under 12 years. We also evaluated its association with age, day care center/school attendance, crowding or other children in the household. POPULATION AND METHODS This cross-sectional study included children aged under 12 years that required blood sampling for surgery. Those with acute infections, chronic diseases or known immunological disorders were excluded. In all cases predictors were recorded, and IgG anti-Mycoplasma pneumoniae determined by enzimoimmunoassay. Association between predictors and seropositivity was evaluated by logistic regression. RESULTS We included 355 children, aged 4.8 +/- 3.1 years. 57.6% attended to day care center/school, crowding was present in 27.3% and 70.1% had other children in the household. IgG antibodies anti-Mycoplasma pneumoniae were present in 12.4%. Seropositives were older than seronegatives (7.1 +/- 3.15 years vs. 4.4 +/- 3.06 years, p < 0.0001). After controlling by confounders, age remains as an independent predictor of seropositivity (OR: 1.19, CI 95%: 1.043-1.362). CONCLUSIONS Seroprevalence of Mycoplasma pneumoniae IgG antibodies in children aged under 12 years was 12.4%. Age is an independent predictor of seropositivity.