Molecular genetic methods in the diagnosis of lower respiratory tract infections

Abstract

Molecular diagnostic techniques, such as PCR, have become useful tools for the rapid etiological diagnosis of lower respiratory tract infections. Nucleic acid amplification tests (NAATs) have been evaluated for detecting most respiratory pathogens, and commercial assays are available for some pathogens. However, standardized protocols are needed before these assays are introduced into routine diagnostic use. For pneumonia, NAATs offer advantages over conventional tests for the detection of Mycoplasma pneumoniae, Legionella spp. and Chlamydia pneumoniae. For pneumococcal pneumonia in adults, PCR adds little to existing diagnostic tests, and is unable to distinguish pneumococcal colonization from infection when testing respiratory samples. Although less sensitive than culture‐based methods, several commercial molecular diagnostic assays have been developed for tuberculosis and are useful rapid tests for selected patients. PCR can now be considered the rapid diagnostic test of choice for pertussis and some respiratory virus infections. Further work is required to better characterize the role of molecular diagnostic tests for diagnosing lower respiratory tract infections, and to develop standard assays that can be readily adopted by routine diagnostic laboratories.

The role of atypical respiratory pathogens in exacerbations of chronic obstructive pulmonary disease

“…Of all pneumonia pathogens, Legionella non-pneumophila spp. probably presents the greatest risk for contamination measured in PCR, given the organism's ubiquitous environmental presence [18]. Owing to the high Ct values observed in both samples, amplification and detection of environmental Legionella DNA cannot be completely excluded.…”

“…Also, variability among authors exists in the reliability and interpretation of the results of serological assays. Molecular diagnostic techniques, such as PCR, have become useful tools for the aetiological diagnosis of lower respiratory tract infections [18]. PCR can detect minute amounts of nucleic acids from potentially all PPMO; it does not depend on the viability of the target microbe; is probably less affected by previous antimicrobial therapy than culturebased methods are; and can provide results quickly.…”

“…For patients with pneumonia, molecular techniques offer distinct advantages over conventional tests for the detection of M. pneumoniae, C. pneumoniae and Legionella spp. [18,19].…”

Evaluation of a multiplex PCR for bacterial pathogens applied to bronchoalveolar lavage

“…While PCR for Legionella spp. applied to bronchoalveolar lavage (BAL) fluid has been found useful [8], PCR for Mycoplasma pneumoniae and Chlamydophila pneumoniae has not been evaluated in BAL samples. However, as sputum samples have been shown to be more useful than upper respiratory tract samples for PCR identification of M. pneumoniae [9,10] and C. pneumoniae [11], and because sputum samples can often not be collected in patients with LRTI, BAL PCR could probably be useful for identification of these two pathogens in LRTI patients.…”

Breathing New Life into Pneumonia Diagnostics

“…Nucleic acid detection tests (NATs), such as PCR, have been developed for all major pneumonia pathogens, although the development of commercial assays and their introduction into routine use by diagnostic laboratories have been relatively slow (7). NATs have many features that make them attractive tools for diagnosing the etiology of respiratory tract infections.…”