Why should we measure bacterial load when treating community-acquired pneumonia?

Abstract

We focus on a number of studies in the past 2 years that herald a dramatic shift in how we treat patients with not just community-acquired pneumonia (CAP), but potentially all sepsis. Recent studies report that high bacterial load, and specifically pneumococcal load in CAP, appears to be significantly associated with worse outcomes. These findings change the sepsis paradigm. Bacterial load may identify potential candidates for adjunctive therapy, ICU admission and more aggressive management. Whereas we all acknowledge the importance of the virulence of the pathogen in the outcome of CAP, microbiological tests currently play little role in management of patients. Whereas molecular tests such as polymerase chain reaction have promised to deliver accurate results in a clinically useful period of time, apart from a few niche situations they have yet to enter routine practice. In particular the ability to calculate the bacterial load in blood, and specifically pneumococcal load in CAP, appears to have significant clinical utility. Not only does bacterial load predict clinical outcome, the data so far available challenge some of our fundamental assumptions about optimal antibiotic therapy and the pathogenesis of severe sepsis.