Ruling out Legionella in community-acquired pneumonia.

Abstract

BACKGROUND:

Assessing the likelihood for Legionella sp. in community-acquired pneumonia is important because of differences in treatment regimens. Currently used antigen tests and culture have limited sensitivity with important time delays, making empirical broad-spectrum coverage necessary. Therefore, a score with 6 variables recently has been proposed. We sought to validate these parameters in an independent cohort.

METHODS:

We analyzed adult patients with community-acquired pneumonia from a large multinational database (Community Acquired Pneumonia Organization) who were treated between 2001 and 2012 with more than 4 of the 6 prespecified clinical variables available. Association and discrimination were assessed using logistic regression analysis and area under the curve (AUC).

RESULTS:

Of 1939 included patients, the infectious cause was known in 594 (28.9%), including Streptococcus pneumoniae in 264 (13.6%) and Legionella sp. in 37 (1.9%). The proposed clinical predictors fever, cough, hyponatremia, lactate dehydrogenase, C-reactive protein, and platelet count were all associated or tended to be associated with Legionella cause. A logistic regression analysis including all these predictors showed excellent discrimination with an AUC of 0.91 (95% confidence interval, 0.87-0.94). The original dichotomized score showed good discrimination (AUC, 0.73; 95% confidence interval, 0.65-0.81) and a high negative predictive value of 99% for patients with less than 2 parameters present.

CONCLUSIONS:

With the use of a large independent patient sample from an international database, this analysis validates previously proposed clinical variables to accurately rule out Legionella sp., which may help to optimize initial empiric therapy.

• Authors: Sebastian Haubitz, Fabienne Hitz, Lena Graedel, Marcus Batschwaroff, Timothy Lee Wiemken, Paula Peyrani, Julio A Ramirez, Christoph Andreas Fux, Beat Mueller, Philipp Schuetz
• Journal: The American journal of medicine (Am J Med) Vol. 127 Issue 10 Pg. 1010.e11-9 (Oct 2014) ISSN: 1555-7162 [Electronic] United States
• PMID: 24813862 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Inc. All rights reserved.

Chemical References

• Anti-Bacterial Agents
• C-Reactive Protein
• L-Lactate Dehydrogenase

Topics

• Aged
• Aged, 80 and over
• Algorithms
• Anti-Bacterial Agents (therapeutic use)
• C-Reactive Protein (analysis)
• Community-Acquired Infections (blood, drug therapy, microbiology)
• Cough
• Databases, Factual
• Decision Making
• Europe
• Female
• Humans
• Hyponatremia (blood)
• L-Lactate Dehydrogenase (analysis)
• Legionella pneumophila (drug effects, isolation & purification)
• Logistic Models
• Male
• Middle Aged
• Multicenter Studies as Topic
• North America
• Platelet Count
• Pneumonia, Bacterial (blood, drug therapy, microbiology)
• Predictive Value of Tests
• South America
• Time Factors