Objective: The aim of this study was to assess the effectiveness of two microbiologic methods: viral culture and serology for the etiologic study of acute respiratory infections in children under 14 years of age admitted to our hospital.
Patients: From January 1992 to December 1993, a prospective study was carried out in 87 patients with a mean age of two years with the following diagnosis: upper respiratory tract infections (URTI) 19, laryngitis 3, bronchitis 18, bronchiolitis 18, and pneumonia 29.
Method: Nasopharyngeal aspirates were collected for virologic culture on cell monolayers in 87 patients. Serologic studies by complement fixation test were carried out in 42 patients older than six months.
Results: The etiologic agent was detected in 54 (62%) of the 87 patients, being the most frequent the respiratory sincitial virus (VRS) with 18 cases (20%), followed by adenovirus (ADV) in 17 (19%) and Mycoplasma pneumoniae in 9 cases (11%). Viral culture was positive in 32 (37%), being ADV in 14 (41%), and RSV in 9 (26%). Significative serologic studies were obtained in 25 (60%) of the 42 studied patients, with VRS in 9 (32%) and M. pneumoniae in 9 (32%). Concerning clinical diagnosis, the major effectiveness corresponded to serology in pneumonia (76%), and to viral culture in URTI (63%).
Conclusion: Viral culture and serology are useful methods for the detection of etiologic agents in acute respiratory infections. The serology effectiveness increases with age (p < 0.01) and the severity of the clinical diagnosis. Both methods have limited usefulness from clinical point of view.