Etiology of community-acquired pneumonia in a population-based study: Link between etiology and patients characteristics, process-of-care, clinical evolution and outcomes

Abstract

BackgroundThe etiologic profile of community-acquired pneumonia (CAP) for each age group could be similar among inpatients and outpatients. This fact brings up the link between etiology of CAP and its clinical evolution and outcome. Furthermore, the majority of pneumonia etiologic studies are based on hospitalized patients, whereas there have been no recent population-based studies encompassing both inpatients and outpatients.MethodsTo evaluate the etiology of CAP, and the relationship among the different pathogens of CAP to patients characteristics, process-of-care, clinical evolution and outcomes, a prospective population-based study was conducted in Spain from April 1, 2006, to June 30, 2007. Patients (age >18) with CAP were identified through the family physicians and the hospital area.ResultsA total of 700 patients with etiologic evaluation were included: 276 hospitalized and 424 ambulatory patients. We were able to define the aetiology of pneumonia in 55.7% (390/700). The most frequently isolated organism was S. pneumoniae (170/390, 43.6%), followed by C. burnetti (72/390, 18.5%), M. pneumoniae (62/390, 15.9%), virus as a group (56/390, 14.4%), Chlamydia species (39/390, 106%), and L. pneumophila (17/390, 4.4%). The atypical pathogens and the S. pneumoniae are present in pneumonias of a wide spectrum of severity and age. Patients infected by conventional bacteria were elderly, had a greater hospitalization rate, and higher mortality within 30 days.ConclusionsOur study provides information about the etiology of CAP in the general population. The microbiology of CAP remains stable: infections by conventional bacteria result in higher severity, and the S. pneumoniae remains the most important pathogen. However, atypical pathogens could also infect patients in a wide spectrum of severity and age.

Atypical pathogen infection in community-acquired pneumonia

“…Atypical pathogens and mixed infections are also significant causes with detectable rates standing at 18% and 14% respectively. Also in Spain, Alberto Capelastegui and his colleagues discovered a 50% detectable rate in a prospective study (24). Atypical pathogens were significantly more frequent among outpatients (67%), than among inpatients(30.6%).…”

Community-acquired pneumonia related to intracellular pathogens

“…These microorganisms might cause severe CAP in approximately 1-7 % [11][12][13]. A retrospective study of 11 patients with ARDS showed that six out of 11 pneumonia cases were caused by C. pneumoniae, and mortality was 100 % in the group of patients with a CURB-65 score of 2 or higher [14].…”

Characterization of the Oxidative Metabolism of Erythrocytes in Patients With Community-Acquired Pneumonia

“…Высокая заболеваемость и смертность при внебольничной пневмонии определяют необхо-димость дальнейших углубленных исследований ме-ханизмов развития и прогрессирования заболевания, поиска путей оптимизации диагностики и терапии. Механизмы развития внебольничных пневмоний раз-нообразны и зависят как от возбудителя, так и от путей проникновения инфекции в легкие [8]. Однако не вы-зывает сомнения ведущая роль свободнорадикального окисления как в развитии, так и в усугублении пато-логического процесса, и вовлеченность в него эритро-цитов.…”