This study seeks to define the indications and the economic impact of the use of antibiotics in infants hospitalized due to bronchiolitis during 2010-2017. There were 459 children with bronchiolitis, median age of 2.2 months, 390 infections with respiratory syncytial virus (RSV), and 69 were non-RSV. Twenty two percent of all these children (102/459) required a workup toward urinary tract co-infections (UTI). A control group, consisting of 8,456 children without bronchiolitis, was created to assess UTI frequency in the general population. We found that 16.0% (73/459) children with bronchiolitis received antibiotics; 63 (13.7%) due to respiratory infection and 9 due to UTI. A time-trend analysis showed a decreasing use of antibiotics, from 57.0% in 2010 to 13.7% in 2017, with the lowest value of 6.4% noticed in 2014. Children treated with antibiotics required a 4-day longer hospitalization than those untreated (p < 0.01), but there were no other clinically relevant differences. After excluding the first 2 years with the highest antibiotic ordering, antibiotics, on average, were used in 9.8% of children with bronchiolitis. Frequency of UTI accompanying bronchiolitis was comparable to that in the control group (8.9% vs. 10.9%, respectively). Specificity of urine culture was 71%, with 100% sensitivity assumed, while the positive predicted value of only 41%. The unnecessary costs of urine cultures, if performed in each patient, would have been €2,236, and with additional laboratory tests in each case of a false positive result it would have reached €5,448. We conclude that antibiotics should be used for bronchiolitis only in justified cases, and their use should not exceed 10% of patients. Since UTI is no more frequent in bronchiolitis than in the general children's population, urine cultures should not be performed routinely.
Keywords: Antibiotics; Bronchiolitis; Children; Infection; Respiratory syncytial virus; Urinary tract infection; Urine culture.