Study objective: To assess the value of the initial microbiological studies (MBS), consisting of sputum Gram's stains, sputum cultures, and blood cultures, in the etiologic diagnosis of community-acquired pneumonia (CAP) without comorbidity.
Design: A prospective study of 74 adult patients hospitalized with nonsevere CAP empirically treated according to the American Thoracic Society guidelines (ATS-GL) and evaluated with Gram's stains and cultures of valid sputum specimens and blood cultures.
Setting: University-affiliated community hospital.
Results: Gram's stain of a valid sputum specimen failed to identify the etiologic agent in all patients. Sputum cultures identified pathogens in only four patients (5%). The results of all blood cultures were negative. All patients responded to the initial empiric antibiotic coverage selected according to the ATS-GL, and the results of the initial MBS had no clinical impact.
Conclusion: The initial MBS, such as sputum Gram's stains, sputum cultures, and blood cultures, have no value in the management of nonsevere CAP without comorbid factors.