Inflammatory response in mixed viral-bacterial community-acquired pneumonia

Research article

Salvador Bello^1*, Elisa Mincholé¹, Sergio Fandos¹, Ana B Lasierra², María A Ruiz³, Ana L Simon¹, Carolina Panadero¹, Carlos Lapresta⁴, Rosario Menendez⁵ and Antoni Torres⁶

• *Corresponding author: Salvador Bello sbello@salud.aragon.es

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BMC Pulmonary Medicine 2014, 14:123  doi:10.1186/1471-2466-14-123

Published: 29 July 2014

Abstract

Background

The role of mixed pneumonia (virus + bacteria) in community-acquired pneumonia (CAP) has been described in recent years. However, it is not known whether the systemic inflammatory profile is different compared to monomicrobial CAP. We wanted to investigate this profile of mixed viral-bacterial infection and to compare it to monomicrobial bacterial or viral CAP.

Methods

We measured baseline serum procalcitonin (PCT), C reactive protein (CRP), and white blood cell (WBC) count in 171 patients with CAP with definite etiology admitted to a tertiary hospital: 59 (34.5%) bacterial, 66 (39.%) viral and 46 (27%) mixed (viral-bacterial).

Results

Serum PCT levels were higher in mixed and bacterial CAP compared to viral CAP. CRP levels were higher in mixed CAP compared to the other groups. CRP was independently associated with mixed CAP. CRP levels below 26 mg/dL were indicative of an etiology other than mixed in 83% of cases, but the positive predictive value was 45%. PCT levels over 2.10 ng/mL had a positive predictive value for bacterial-involved CAP versus viral CAP of 78%, but the negative predictive value was 48%.

Conclusions

Mixed CAP has a different inflammatory pattern compared to bacterial or viral CAP. High CRP levels may be useful for clinicians to suspect mixed CAP.

Keywords: 

Community-acquired pneumonia; Viral pneumonia; Biomarkers