Risk factors and outcome of community-acquired pneumonia due  to Gram-negative bacilli.
OBJECTIVE
Several sets of guidelines have advocated initial antibiotic treatment for community-acquired pneumonia due to Gram-negative bacilli in patients with specific risk factors. However, evidence to support this recommendation is scarce. We sought to identify risk factors for community-acquired pneumonia due to Gram-negative bacilli, including Pseudomonas aeruginosa, and to assess outcomes.


METHODS
An observational analysis was carried out on prospectively collected data for immunocompetent adults hospitalized for community-acquired pneumonia in two acute-care hospitals. Cases of pneumonia due to Gram-negative bacilli were compared with those of non-Gram-negative bacilli causes.


RESULTS
Sixty-one (2%) of 3272 episodes of community-acquired pneumonia were due to Gram-negative bacilli. COPD (odds ratio (OR) 2.4, 95% confidence interval (CI): 1.2-5.1), current use of corticosteroids (OR 2.8, 95% CI: 1.2-6.3), prior antibiotic therapy (OR 2.6, 95% CI: 1.4-4.8), tachypnoea >or=30 cycles/min (OR 2.1, 95% CI: 1.1-4.2) and septic shock at presentation (OR 6.1, 95% CI: 2.5-14.6) were independently associated with Gram-negative bacilli pneumonia. Initial antibiotic therapy in patients with pneumonia due to Gram-negative bacilli was often inappropriate. These patients were also more likely to require admission to the intensive care unit, had longer hospital stays, and higher early (<48 h) (21% vs 2%; P < 0.001) and overall mortality (36% vs 7%; P < 0.001).


CONCLUSIONS
These results suggest that community-acquired pneumonia due to Gram-negative bacilli is uncommon, but is associated with a poor outcome. The risk factors identified in this study should be considered when selecting initial antibiotic therapy for patients with community-acquired pneumonia.
Falguera
Miquel
M
Internal Medicine Service, Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Hospital Universitari Arnau de Vilanova, University of Lleida, Lleida, Spain. mfalguera@comll.cat
Carratalà
Jordi
J
Ruiz-Gonzalez
Agustín
A
Garcia-Vidal
Carolina
C
Gazquez
Isabel
I
Dorca
Jordi
J
Gudiol
Francesc
F
Porcel
José M
JM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000453:epidemiology*; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000453:epidemiology; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents