Shared by Robert Mahoney
Link: http://www.journals.uchicago.edu/doi/abs/10.1086/591405

Novel approaches to the identification of Streptococcus pneumoniae as the cause of community-acquired pneumonia.

Clin Infect Dis. 2008 Dec 1;47 Suppl 3:S202-6

Authors: Klugman KP, Madhi SA, Albrich WC

Current diagnostic tests lack sensitivity for the identification of the bacterial etiology of pneumonia. Attempts during the past 2 decades to improve sensitivity of detection of bacterial constituents in blood by use of antibody-antigen complexes and polymerase chain reaction have been disappointing. Recent data using pneumococcal conjugate vaccines as probes suggest that increased levels of both C-reactive protein and procalcitonin may be useful adjuncts to chest radiographs in the selection of patients with presumed bacterial pneumonia for inclusion in clinical trials. Among pneumococcal diagnostics currently under investigation, quantitative real-time polymerase chain reaction of respiratory secretions, as well as urinary antigen detection and pneumococcal surface adhesin A serological analysis for adults, are candidates for use in future clinical trials of antibiotics.

PMID: 18986290 [PubMed - in process]

Is activity against "atypical" pathogens necessary in the treatment protocols for community-acquired pneumonia? Issues with combination therapy.

Clin Infect Dis. 2008 Dec 1;47 Suppl 3:S232-6

Authors: Bartlett JG

The "atypical pathogens" reviewed include Legionella pneumophila, Chlamydophilia pneumoniae, and Mycoplasma pneumoniae. Urinary antigen tests are the most frequently used tests for Legionella species and show good specificity and reasonable sensitivity. For M. pneumoniae, detection of immunoglobulin M, used for the past decade, has substantially improved diagnostic specificity and has simplified testing. For C. pneumoniae, there is no consensus on a simplified test that can be commonly used, and the reported results, with the use of tests that have not been well validated for diagnostic accuracy, show great variation in prevalence. With regard to therapeutic trials, 3 meta-analyses have recently addressed the issue of clinical outcome with or without antibiotics directed against atypical pathogens (macrolides or fluoroquinolones vs. beta-lactam agents). These analyses have not been able to demonstrate any clinical benefit, except in a subset analysis of infections caused by L. pneumophila. Nevertheless, multiple studies from the 1950s and 1960s supported a clinical benefit of tetracycline or erythromycin treatment for infections caused by M. pneumoniae. The largest uncontrolled review of antibiotic treatment for hospitalized patients with community-acquired pneumonia demonstrated a clear benefit from the use of macrolides plus cephalosporins or fluoroquinolones, compared with the use of beta-lactams alone, although these data support a potential role for atypical agents, because other potential explanations make drawing conclusions difficult. With regard to future studies, it is noted that the standard of care in the United States, Canada, and some other countries is routine use of agents to treat infection with atypical pathogens, which makes the conduct of controlled trials to address these issues ethically difficult and practically impossible. Additional limitations are the difficulty in diagnostic testing for C. pneumoniae and the importance of rapid institution of therapy for patients severely ill enough to require hospitalization. These observations introduce substantial ethical and logistical barriers to studies of specific agents, except by retrospective analyses.

PMID: 18986295 [PubMed - in process]