ABSTRACT
Introduction .................................................................................................................................... 610 Clinical Importance of Mycobacteria ............................................................................................ 610
Mycobacterium tuberculosis Complex ...................................................................................... 610 Resistance to Antituberculosis Drugs ................................................................................... 611
Nontuberculous Mycobacteria .................................................................................................. 611 Clinically Signicant Species of Slow-Growing Mycobacteria .................................................... 611
Mycobacterium leprae .............................................................................................................. 611 Mycobacterium ulcerans ........................................................................................................... 612 Mycobacterium avium Complex (MAC) ................................................................................... 612 Mycobacterium haemophilum ................................................................................................... 613 Mycobacterium kansasii............................................................................................................ 613 Mycobacterium malmoense ....................................................................................................... 613 Mycobacterium xenopi .............................................................................................................. 613 Mycobacterium celatum ............................................................................................................ 613 Mycobacterium marinum .......................................................................................................... 614
Clinically Signicant Species of Rapidly Growing Mycobacteria ................................................ 614 Detection and Isolation of Mycobacteria from Clinical Specimens .............................................. 615
Specimen Selection ................................................................................................................... 615 Specimen Processing ................................................................................................................. 616 Staining of Smears .................................................................................................................... 617 Isolation of Mycobacteria from Clinical Specimens (Culture) ................................................. 617
Solid Media .......................................................................................................................... 617 Liquid Media ........................................................................................................................ 618 MGIT 960 System ................................................................................................................ 618
Direct Testing of Specimens for Mycobacterium tuberculosis using Molecular Methods ............ 618 Identication of Mycobacteria ....................................................................................................... 619 Drug Susceptibility Testing of Mycobacteria ................................................................................ 620
Culture-Based Drug Susceptibility Testing ............................................................................... 620 Solid Media .......................................................................................................................... 620 Liquid Media ........................................................................................................................ 621
Molecular-Based Drug Susceptibility Testing .......................................................................... 621 Summary ........................................................................................................................................ 622 Acknowledgment ........................................................................................................................... 622 References ...................................................................................................................................... 622
Mycobacteria belong to the family Mycobacteriaceae. These organisms are characterized by possessing elevated lipid content, most notably a high level of waxes called mycolic acids [1]. Mycolic acid contents vary among different species of mycobacteria. These mycolic acids are responsible for the organism being resistant to decolorization by acid alcohols during staining of these bacteria by Ziehl-Neelsen (ZN) staining method. These cells are referred to as being acid-fast bacteria (AFB). This staining test is often the rst test performed on a clinical specimen from a suspected case. This test is also used to determine if the patient is potentially infectious. Especially in the tuberculosisendemic areas, the smear result is considered diagnostic. Any patient with an acid-fast-positive smear would be considered potentially infectious and would require patient isolation.
