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Category: Bacterial Pathogenesis; Clinical Microbiology
Molecular Diagnosis of Mycobacterial Infections, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555817657/9781555812959_Chap06-1.gif /docserver/preview/fulltext/10.1128/9781555817657/9781555812959_Chap06-2.gifAbstract:
Clinical mycobacteriology laboratories play a key role in the control of the spread of tuberculosis (TB) through the timely detection, isolation, identification, and drug susceptibility testing of Mycobacterium tuberculosis isolates. With the use of amplification systems, nucleic acid sequences can be detected directly in clinical specimens, offering better accuracy than acid-fast bacillus (AFB) smear and greater speed than culture. The LCx (ligase chain reaction) MTB assay detects the gene for the PAB protein, and is based on probe amplification and recommended for respiratory specimens. The ProbeTec Direct TB system is based on strand displacement amplification, which is an isothermal enzymatic process that amplifies DNA exponentially. TB assay can detect the presence of both M. tuberculosis and its resistance to rifampin and is discussed in the chapter. During the last two decades, mycobacteriology laboratories have realized important advances in mycobacterial identification through the application of molecular biology techniques. It may be useful to be able to identify the increasingly recognized M. bovis subspecies caprae and M. tuberculosis subspecies canettii. Drugs administered in the therapy of TB mainly include compounds which inhibit cell wall synthesis (isoniazid [INH], ethambutol [EMB]), transcription (rifampin [RMP]), protein synthesis (streptomycin [SM] and other aminoglycosides), and nucleic acid synthesis (fluoroquinolones such as ofloxacin). The application of molecular testing methods in the mycobacteriology laboratory has the potential to significantly improve one’s ability to detect M. tuberculosis directly in clinical specimens or cultures as well as to differentiate mycobacterial species and drug-resistant strains.
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Molecular biology techniques commonly used to detect of mutations causing M. tuberculosis resistance to antimicrobial agents.
Molecular biology techniques commonly used to detect of mutations causing M. tuberculosis resistance to antimicrobial agents.