Rate and Predictors of Bacteremia in Afebrile Community-Acquired Pneumonia

Published:October 26, 2019DOI:


      Although blood cultures (BCs) are the “gold standard” for detecting bacteremia, the utility of BCs in patients with community-acquired pneumonia (CAP) is controversial. This study describes the proportion of patients with CAP and afebrile bacteremia and identifies the clinical characteristics predicting the necessity for BCs in patients who are afebrile.


      Bacteremia rates were determined in 4,349 patients with CAP enrolled in the multinational cohort study The Competence Network of Community-Acquired Pneumonia (CAPNETZ) and stratified by presence of fever at first patient contact. Independent predictors of bacteremia in patients who were afebrile were determined using logistic regression analysis.


      Bacteremic pneumonia was present in 190 of 2,116 patients who were febrile (8.9%), 101 of 2,149 patients who were afebrile (4.7%), and one of 23 patients with hypothermia (4.3%). Bacteremia rates increased with the CURB-65 score from 3.5% in patients with CURB-65 score of 0 to 17.1% in patients with CURB-65 score of 4. Patients with afebrile bacteremia exhibited the highest 28-day mortality rate (9.9%). Positive pneumococcal urinary antigen test (adjusted OR [AOR], 4.6; 95% CI, 2.6-8.2), C-reactive protein level > 200 mg/L (AOR, 3.1; 95% CI, 1.9-5.2), and BUN level ≥ 30 mg/dL (AOR, 3.1; 95% CI, 1.9-5.3) were independent positive predictors, and antibiotic pretreatment (AOR, 0.3; 95% CI, 0.1-0.6) was an independent negative predictor of bacteremia in patients who were afebrile.


      A relevant proportion of patients with bacteremic CAP was afebrile. These patients had an increased mortality rate compared with patients with febrile bacteremia or nonbacteremic pneumonia. Therefore, the relevance of fever as an indicator for BC necessity merits reconsideration.

      Key Words


      AOR (adjusted OR), BC (blood culture), CAP (community-acquired pneumonia), CAPNETZ (The Competence Network of Community-Acquired Pneumonia), CRP (C-reactive protein)
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        CHESTVol. 158Issue 3
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          In daily clinical routine, at the ED, the clinical diagnosis of community-acquired pneumonia is occasionally a cop-out diagnosis (eg, in patients with cardiac decompensation and increased inflammatory parameters). In those cases, positive blood cultures (BCs) may reveal other infectious foci. In particular, bacteremia caused by Staphylococcus aureus or Enterococcus species requires a different diagnostic and therapeutic management.1,2 In our recent study, 30 of 292 patients (10.3%) with bacteremia had growth of S aureus or Enterococcus species in blood, and at least one patient had prosthetic valve endocarditis.
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      • Low Yield, High Costs: The Futility of Blood Cultures in Pneumonia
        CHESTVol. 158Issue 3
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          In a past issue of CHEST (March 2020), Forstner et al1 state that the use of blood cultures (BCs) in patients with community-acquired pneumonia (CAP) is controversial. We agree. However, their results delineate a manifesto against the routine collection of BC in patients with CAP. Consistent with the findings of previous studies,2-4 the vast majority of BC in patients with CAP yield negative results. In this study 3996 of 4349 patients (91.9%) were reported to have negative BC results. Moreover, after the isolation of Streptococcus pneumonia (158 patients), growth of bacteria consistent with contamination was the second most prevalent finding (61 patients).
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