Nonculture Methods For The Identification Of Pathogenic Microorganisms
المؤلف:
Stefan Riedel, Jeffery A. Hobden, Steve Miller, Stephen A. Morse, Timothy A. Mietzner, Barbara Detrick, Thomas G. Mitchell, Judy A. Sakanari, Peter Hotez, Rojelio Mejia
المصدر:
Jawetz, Melnick, & Adelberg’s Medical Microbiology
الجزء والصفحة:
28e , p52-53
2025-05-24
453
Attempts to estimate total numbers of eubacteria and archae bacteria are problematic because of difficulties such as detection in and recovery from the environment. As indicated earlier, estimates indicate that the numbers of unculturable microbial taxa greatly exceed those of the culturable organisms. Recent estimates suggest that the number of bacterial species in the world is between 107 and 109. Until very recently, microbial identification required the isolation of pure cultures followed by testing for multiple physiologic and biochemical traits. Clinicians have long been aware of human diseases that are associated with visible but nonculturable microorganisms. Scientists are now using a PCR-assisted approach using rRNA as a tar get to identify pathogenic microorganisms in situ. The first phase of this approach involves the extraction of DNA from a suitable specimen, the PCR amplification of the ribosomal DNA, the sequencing of the rRNA sequence information, and a comparative analysis of the retrieved sequences. This yields information on the identity or relatedness of the sequences in comparison with the available database. This approach has been used in the identification of pathogenic microorganisms. For example, a previously uncharacterized pathogen has been identified as the Whipple-disease–associated rod-shaped bacterium now designated Tropheryma whipplei. This rRNA approach has also been used to identify the etiologic agent of bacillary angiomatosis as Bartonella henselae and to show that the opportunistic pathogen Pneumocystis jiroveci is a member of the fungi. Undoubtedly, these and other techniques will identify additional etiologic agents in the future.
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