[Usefulness of etiologic studies in children hospitalized for pneumonia]

The aims of this study were: 1) To assess the effectiveness of viral culture and serology. 2) To check if there are clinical differences between patients with viral or bacterial infections. 3) Assessment of treatment, previous to and during the hospital stay.

A prospective study was carried out between January 1994 and June 1995 on 56 inpatients diagnosed of pneumonia. The mean age was 3 years (range: 2 months- 14 years). Viral cultures on cell monolayers was carried out in 46 patients. Serology was carried out in 33 patients older than six months of age. Blood cultures were obtained in 27 patients and a tuberculine reaction was studied in 15 patients. On the basis of microbiological results, three groups were formed (viral, bacterial and unknown) and clinical symptoms, thorax X-rays, and laboratory data were compared.

The etiologic agent was detected in 36 patients (64%). The most frequent pathogens detected were adenovirus and respiratory syncytial virus with 11 patients (19%) each, followed by Mycoplasma pneumoniae with 9 patients (16%): Viral cultures were positive in 16 patients (35%) and serology in 22 patients (66%). Viral infection was detected in 20 patients (36%) and bacterial infection in 16 (28%). Mixed infection (bacterial/viral) was found in 5 patients (9%). The patients with viral infections showed significant differences (p < 0.01) for age (younger) and tachypnea compared with those with bacterial infections. Sixty-six percent of the patients had received antibiotic treatment previous to hospital admission and 87% during their hospitalization.

Although the etiologic studies were positive in 64% of the patients, the delay in obtaining the results make them scarcely useful in determining whether to initiate or not antibiotic therapy (87% of inpatients). Clinical data, radiology results and leukocyte counts do not show any difference between viral and bacterial infections.