[Associated risk factors for serious bacterial illness in children less than 24 months, admitted with fever without source]. / Factores asociados a riesgo de infección bacteriana grave en niños bajo 24 meses de edad, internados por fiebre sin foco aparente.

OBJECTIVES: To analyze risk factors for serious bacterial illness (SBI) in children less than 2 years of age admitted with fever without source. POPULATION: Children under 2 years admitted at the Pediatric Service of Sanatorio Mater Dei from May 2004 to December 2005. DESIGN: Observational, prospective and longitudinal study. INDEPENDENT VARIABLES: age, gender, siblings, household viral infections, day care attendance, vaccination, season, laboratory data, Rochester criteria, YIOS scale, antibacterial treatment, length of hospitalization, and final diagnosis. A multiple logistic regression stepwise model was used. RESULTS: 70 out of 201 patients developed SBI, 56 were under 3 months of age. Predominant diagnosis were: urinary tract infection (n: 47), meningitis (n: 11) and bacteremia (n: 9). Predictive factors: white-cells count > 15.000/mm3 (coef 1.05, OR = 2.17, 95% CI 1.13-4.15) and household viral contact (coef-0.79, OR 0.42, CI 0.23-0.77). CONCLUSIONS: Risk factor for SBI was leucocytes count >15.000/mm3. Household viral contact proved being a protective factor.