RESUMEN
The composition of the upper respiratory tract microbiome may play an important role in the development of lower respiratory tract infections. Here, we characterised the microbiome of the nasopharynx and oropharynx of hospitalised patients with community-acquired pneumonia (CAP) with unknown aetiology in an attempt to obtain insight into the aetiology of CAP. A random sample of 10 patients hospitalised with CAP previously enrolled in a separate clinical trial (ClinicalTrials.gov registry, Study ID: NCT01248715) in which a complete microbiological workup was not able to define an aetiology were analysed in this pilot study. This larger trial (n = 1,221) enrolled patients from 9 adult hospitals in Louisville, Kentucky, USA. Nasopharyngeal and oropharyngeal swabs were obtained for metagenomic analysis. Polymerase chain reaction (PCR) for Streptococcus pneumoniae was performed in all patients. One patient had a distinct nasophararyngeal microbiome consisting largely of Haemophilus influenzae. This was the only patient with a negative PCR for S. pneumoniae in both nasophararyngeal and oropharyngeal specimens. Overall, substantial differences were found between nasophararyngeal and oropharyngeal microbiomes. The upper respiratory tract microbiome of only one patient suggested H. influenzae as a probable aetiology of CAP. Although this was a pilot study of only 10 patients, the presence of S. pneumoniae in the upper respiratory tract of the other 9 patients warrants further investigation.
RESUMEN
BACKGROUND: The association of hospitalization because of community-acquired pneumonia (CAP) and long-term survival has not been fully examined. We measured the long-term survival of hospitalized patients with CAP adjusted for the effects of comorbidities. METHODS: A cohort of adult patients admitted to the medical services of the Veterans Affairs Medical Center, Louisville, Kentucky, was retrospectively examined. A Kaplan-Meier survival curve was constructed to assess the effect of CAP admission status on patient survival. A Cox proportional hazards regression model included comorbidities as predictors and time to death as the outcome in the construction of a modified Charlson Comorbidity Index (mCCI). The mCCI was internally validated to evaluate the predictability of patient survival. The mCCI and age > 65 years were included as potential confounders in a final Cox proportional hazards regression model with CAP admission status as the main predictor and time to death as the outcome. RESULTS: CAP was identified in 624 (9%) out of 6,971 patients. The Kaplan-Meier survival curve showed a significantly shorter survival among patients with CAP than those without CAP (P < .0001). The internal validation of the mCCI showed that patients were more likely to die as the mCCI increased (P < .0001). The Cox proportional hazards regression modeling the association between time to death and CAP admission after adjusting for elderly age and the mCCI showed that hospitalization due to CAP was a statistically significant predictor of decreased survival (hazard ratio, 1.4; 95% CI, 1.2-1.5; P < .0001). CONCLUSION: There is a decreased long-term survival among hospitalized patients with CAP after adjusting for comorbidities and aging. Future research to understand the pathophysiology of the long-term CAP outcomes is necessary to develop treatment strategies.