Etiology of bacteremias associated with c-reactive protein, procalcitonin and lactate levels

Introduction

Because of the high morbidity and mortality associated with bacteremia, prompt evaluation and adequate therapy are of paramount importance. The clinical manifestations of gram- positive and gram-negative bacterial infections are similar while biomarkers may be useful for the early diagnosis of the nature of a pathogen.

Objectives

The purpose of the study was to evaluate the association between the level of C-Reactive Protein (CRP), procalcitonin (PCT), and lactate and the etiology of bacteremia.

Methods

We studied the role of these biomarkers with clustered gram-positive and gram-negative bacteremia in patients hospitalized in Intensive care Unit over a period of 2 years (2011-2013), they were measured within the 24 hours after the onset of severe sepsis or septic shock. The PCT was analyzed by immunoassay (Vidas, Brahms)®, lactate and CRP was measured in DIMENSION RXL - SIEMENS^® and blood culture was made in BACTEC-9240^® blood culture system (Becton Dickinson). The program used for the data processing and statistical analysis was SPSS 15.0^®.

Results

Our study included 396 patients, the median age of the study sample was 64 years old (inter-quartile range (IQR), 51-72), 60,6% were men, the main sources of infection were: respiratory tract (36%) and intra-abdomen (26%). In our series, APACHE II scores was 25 (IQR: 21-29.5), SOFA 10 (IQR: 7.75-11) and 24.8%of 28-day mortality. Blood cultures were realized in 316 patients (79.9%), 192 were negative and 7 cases the result were fungi, 58.62% had bacteremia due to gram-negative bacteria and 41.38% due to gram-positive, with 43 isolations Escherichia coli, were the most frequently isolated bacterium followed by Streptococcus pneumoniae (16.43%) and Enterobacteria (14.29%).

In the gram-negative bacteremia group, CRP levels plasma were higher 261 [IQR: 173.19-311.53] mg/dL vs. 200.2 [159.5-287.75] mg/dL than in the gram-positive bacteremia group, however PCT concentrations were statistically significant higher in the gram-negative bacteremia 27.04 [IQR: 13.47-84.23] ng/mL vs. 11.79 [2.61-22.67] ng/mL; p < 0.001; as well as lactate levels 3.1 [IQR: 1.97-4.7] mmol/L vs. 2.45 [1.64-4.22] mmol/L; p = 0.04.

Conclusions

PCT and lactate showed differences between gram-negative and gram-positive bacteremia, might be helpful in the differentiation of pathogenic bacteriemia and supposed the etiology before obtaining blood culture results.