Severity of Pneumococcal Pneumonia Associated With Genomic Bacterial Load.
Chest. 2009 May 11;
Authors: Rello J, Lisboa T, Lujan M, Gallego M, Kee C, Kay I, Lopez D, Waterer GW
Background There is a clinical need for more objective methods of identifying patients at risk for septic shock and poorer outcomes in community-acquired pneumonia (CAP). As viral load is useful in viral infections, we hypothesized that bacterial load may be associated with outcomes in pneumococcal pneumonia. Methods Quantification of S. pneumoniae DNA level by real time-PCR was prospectively conducted on whole-blood in a cohort of 353 patients presenting with CAP at Emergency Department. Results CAP caused by S. pneumoniae was documented in 93 patients(36.5% with positive blood cultures). A positive S. pneumoniae rt-PCR assay was associated with a statistically significant higher mortality (OR = 7.08), risk for shock (OR = 6.29), and need for Mechanical Ventilation (MV) (OR = 7.96). Logistic regression, adjusted for age, sex, comorbidities and PSI class, revealed bacterial load as independently associated with septic shock (aOR = 2.42 95%CI 1.10-5.80) and need for MV (aOR = 2.71 95%CI 1.17-6.27). S. pneumoniae bacterial load of >/= 10(3) copies/mL occurred in 29.0% of patients (27/93; 95%CI 20.8%-38.9%) being associated with statistically significant higher risk for septic shock (OR = 8.00), need for MV (OR = 10.50) and hospital mortality (OR = 5.43). Conclusion In pneumococcal pneumonia, bacterial load is associated with likelihood of death, risk of septic shock, and need for MV. High genomic bacterial load for S. pneumoniae may be a useful tool for severity assessment.
PMID: 19433527 [PubMed - as supplied by publisher]