Can we predict pneumococcal bacteremia in patients with severe community-acquired pneumonia? ☆ , ☆☆ José Manuel Pereira MD a, b, ⁎, Armando Teixeira-Pinto PhD c , Carla Basílio MD a , Conceição Sousa-Dias MD a , Paulo Mergulhão MD a, b , José Artur Paiva MD, PhD a, b a Emergency and Intensive Care Department, Centro Hospitalar S. João EPE, Porto, Portugal b Faculdade de Medicina da Universidade do Porto, Porto, Portugal c Screening and Test Evaluation Program, Sydney School of Public Health, University of Sydney, Sydney, Australia abstract article info Keywords: Bacteremia Biomarkers Community-acquired pneumonia Pneumococcus Procalcitonin Purpose: This study aimed to evaluate the role of biomarkers as markers of pneumococcal bacteremia in severe community-acquired pneumonia (SCAP). Materials and Methods: A prospective, single-center, observational cohort study of 108 patients with SCAP admitted to the intensive care department of a university hospital in Portugal was conducted. Leucocytes, C- reactive protein (CRP), lactate, procalcitonin (PCT), D-dimer, brain natriuretic peptide (BNP), and cortisol were measured within 12 hours after the first antibiotic dose. Results: Fifteen patients (14%) had bacteremic pneumococcal pneumonia (BPP). They had significantly higher levels of median CRP (301 [interquartile range, or IQR], 230-350] mg/L vs 201 [IQR, 103-299] mg/L; P = .023), PCT (40 [IQR, 25-102] ng/mL vs 8 [IQR, 2-26] ng/mL; P b .001), BNP (568 [IQR, 478-2841] pg/mL vs 407 [IQR, 175-989] pg/mL; P = .027), and lactate (5.5 [IQR, 4.5-9.8] mmol/L vs 3.1 [IQR, 1.9-6.2] mmol/L; P = .009) than did patients without BPP. The discriminatory power evaluated by the area under the receiver operating characteristic curve (aROC) for PCT (aROC, 0.79) was superior to lactate (aROC, 0.71), BNP (aROC, 0.67), and CRP (aROC, 0.70). At a cutoff point of 17 ng/mL, PCT showed a sensitivity of 87%, a specificity of 67%, a positive predictive value of 30% and a negative predictive value of 97%, as a marker of pneumococcal bacteremia. Conclusions: In this cohort, significantly higher PCT, BNP, lactate, and CRP levels were found in BPP, and PCT presented the best ability to identify pneumococcal bacteremia. A PCT serum level lower than 17 ng/mL could identify patients with SCAP unlikely to have pneumococcal bacteremia. © 2013 Elsevier Inc. All rights reserved. 1. Introduction Community-acquired pneumonia (CAP) remains one of the leading causes of hospital admission and represents a burden to the health care system [1]. In recent decades, mortality among hospital- ized patients with CAP has been reduced, but it remains elevated among patients admitted to the intensive care unit (ICU) [2-4]. Streptococcus pneumoniae is the leading pathogen, and approxi- mately 20% of cases of pneumococcal pneumonia occur with bacteremia [5], leading to a mortality in the range of 15% to 36% [6-9]. Combination therapy, namely, the combination of a macrolide or a “respiratory” fluoroquinolone with a β-lactam, is advocated for the treatment for all patients with severe CAP [10-12]. This recommendation is supported mostly by retrospective and non- randomized studies [13-17] that showed a lower mortality rate with combination therapy, namely, in patients with pneumococcal bacteremia. Combination therapy is also associated with a better outcome in patients with septic shock [18] and in mechanically ventilated patients [19]. However, empiric use of combination therapy to all patients with severe CAP may lead to antibiotic overuse and resistance emergence, and in fact, avoiding the unnecessary use of antibiotics is the best way to reduce antibiotic pressure and decrease the emergence of antimicrobial resistance. Whether it is possible to avoid using combination therapy in some patients with severe CAP remains an open question. Patients without Journal of Critical Care 28 (2013) 970–974 Abbreviations: CAP, community-acquired pneumonia; ICU, intensive care unit; COPD, chronic obstructive pulmonary disease; SAPS, Simplified Acute Physiology Score; PIRO, Predisposition, Insult, Response, Organ Failure; SOFA, Sepsis-related Organ Failure Assessment; PSI, Pneumonia Severity Index; WBC, leukocyte count; PCT, procalcitonin; CRP, C-reactive protein; BNP, Brain natriuretic peptide; SD, standard deviation; IQR, 25th to 75th interquartile range; ROC, receiver operating characteristics; aROC, area under the receiver operating characteristics curve; sTREM, soluble form of triggering receptor expressed on myeloid cells 1. ☆ Conflict of interest: The authors declare that they have no competing interests. ☆☆ Authors' contributions: All authors have made substantial contribution to the conception and design of the study as well as to the drafting, revising, and final approval of the version to be published. J.M.P. and A.T.P. performed statistical analysis. ⁎ Corresponding author. Emergency and Intensive Care Department, Centro Hospitalar S. João EPE, Faculdade de Medicina da Universidade do Porto, Al Prof Hernâni Monteiro, 4200-319 Porto, Portugal. Tel.: +351 916865661. E-mail address: jmcrpereira@yahoo.com (J.M. Pereira). 0883-9441/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcrc.2013.04.016 Contents lists available at ScienceDirect Journal of Critical Care journal homepage: www.jccjournal.org