Characteristics of patients with community-acquired bacteremia who have low levels of C-reactive protein (≤20 mg/L)

Abstract

Objectives: To characterize patients presenting with community-acquired bacteremia and a low C-reactive protein (CRP) plasma level at date of bacteremia.

Methods: Population-based cohort study. Patient characteristics were compared for three CRP groups (≤20 mg/L, 21-100 mg/L and >100 mg/L) using chi-square test and oneway anova. The 30-day mortality rates were compared using logistic regression analyses.

Results: Of the 2017 patients included, 193 (9.6%) had a CRP ≤20 mg/L. These patients were younger, more likely to be male, overrepresented in the intensive care unit and had more comorbidities. In blood cultures from the low CRP group hemolytic streptococci and coagulase-negative staphylococci were found relatively more common, whereas Streptococcus pneumoniae or Staphylococcus aureus were found relatively less common compared to the other CRP groups. The majority of patients with an initial low CRP mounted a CRP response the following days. The 30-day mortality rate was lower in the low CRP group (13.5%) than in the group with CRP >100 mg/L (20.6%).

Conclusions: A considerable proportion of patients with community-acquired bacteremia has a normal or low initial CRP level. The plasma CRP level should not be used to rule out serious infection or withhold antibiotic therapy.

Keywords: C-reactive protein; Coagulase-negative staphylococci; Community-acquired bacteremia; Hemolytic streptococci.