Diagnostics and Clinical Disease Treatment
Paul C. Lück
from: Legionella: Molecular Microbiology (Edited by: Klaus Heuner and Michele Swanson). Caister Academic Press, U.K. (2008)
Abstract
The methods currently available to diagnose Legionnaires' disase are culture, urinary antigen detection, direct fluorescent antibody testing, detection of nucleic acid and detection of specific antibodies in serum samples. The advantages and limitations of each method are discussed. Presently, none of the diagnostic tests available offers the desired quality with respect to sensitivity and specificity. Culture should be obligatory, especially when hospitalized patients with underlying diseases are investigated. A positive culture is the prerequisite of molecular epidemiological investigations. Urinary antigen detection is a valuable tool in the majority of community-acquired cases when L. pneumophila serogroup 1 is the causative agent. In cases of nosocomial disease, when Legionella pneumophila serogroups other than sg 1 are frequent, this assay has limitations. The detection of nucleic acid is very promising, but needs further validation. The detection of antibodies in a patient's serum is of little use in the acute phase of the illness. Several molecular subtyping techniques are in use to subtype L. pneumophila strains in epidemiological investigations. Legionella pneumophila is genetically very heterogeneous thus allowing an individual fingerprint of each strain. However, the majority of clinical cases are caused by a limited number of clones that cause disease worldwide. The therapy of for Legionnaires' disease requires drugs that can access and are active intracellularly. Currently, fluorochinolones and macrolides are the most active agents read more ...
