Seminars in respiratory infections
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The second most common nosocomial infection in the United States is pneumonia, with the highest rates seen in patients requiring mechanical ventilation. Nosocomial pneumonia is a serious disease associated with significant morbidity and mortality; crude mortality rates have been estimated at 20% to 50%. The rapid institution of appropriate antimicrobial therapy has been shown to improve mortality in patients with ventilator associated nosocomial pneumonia. ⋯ There are, however, many challenges which confront the laboratory including: the ability to identify organisms from an extensive microbiologic spectrum; distinguishing colonization from infection of predominately gram-negative oropharyngeal flora; and providing timely results. This article reviews the various diagnostic tests available for nosocomial lung infections, and in particular, ventilator associated pneumonia including: blood cultures; pleural fluid; expectorated sputum; endotracheal aspirates; and respiratory specimens obtained by more invasive techniques using bronchoscopy and transthoracic needle aspiration. Emphasis is placed on optimal specimen collection, the processing of samples in the laboratory, and on the evaluation of potential risks and benefits associated with the varying techniques.
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Semin Respir Infect · Jun 2000
ReviewPneumonia in the immunocompromised host: the role of bronchoscopy and newer diagnostic techniques.
The microbiology laboratory plays an essential role in the laboratory diagnosis of pneumonia in the immunocompromised host. Both the diversity of underlying or predisposing host conditions that increase risk for pneumonia and the variety of microbial agents that may be etiologically responsible make the laboratory's role in the diagnostic process a challenging one. ⋯ Respiratory specimens available for testing are also diverse and are often obtained by the use of fiberoptic bronchoscopy, but may be complemented by use of blood samples when dissemination is likely or more recently by urinary antigen testing in select cases. Given the large number of variables in the design of a diagnostic approach to pneumonia in the immunocompromised host, it is critical that laboratorians and clinicians cooperate in the development of protocols that are cost effective and appropriate to their specific clinical settings.