Impact of Blood Cultures on the Changes of Treatment in Hospitalized Patients with Community-Acquired Pneumonia

Initial blood cultures (BCs) with severe community-acquired pneumonia (CAP) are warranted. However, other than severity, the specific contributing factors that affect the decision to change antimicrobial agents have not been evaluated previously.

Consecutive adults with CAP hospitalized between January 2008 and December 2010 were assessed retrospectively. We enrolled those who were over 18 years old with typical symptoms of pneumonia and with an infiltrate consistent with pneumonia, from which 2 sets of BCs were obtained. Those who had been immunocompromised, hospitalized, or prescribed antibiotics in the past 30 days were excluded. We retrospectively assessed the factors contributing to the change in antimicrobial agents as well as the frequency of these changes in the enrolled patients based on the initial BC results.

In total, 793 patients with initial diagnosis of CAP were admitted; 399 met the inclusion criteria. Among them, 386 were made definitive diagnosis of CAP after admission (the remaining 13 were made alternative diagnosis [non-pneumonia illnesses]). BC results were positive in 17 (4.4%) out of 386 CAP patients, among whom antimicrobial therapy was changed based on the BC results in 8 (2.1%) (Pneumonia Severity Index [PSI] grade IV; 2, PSI grade V; 6). Alternative diagnosis after admission was contributing factors for changing antimicrobial agents based on the positive blood culture results.

The use of BCs should be limited to patients with very severe cases. It would be helpful to find alternative diagnosis and modify treatment.