DIAGONOSIS OF
MYCOBACTERIUM TUBERCULOSIS BY
MUHAMMAD ZADA
Introduction
Pathogenic bacteria of mycobacteraceae familyAerobic bacilli –non spore forming
non motileCell wall –rich in lipidsAcid-fast bacilliVery slow growingRoute of transmission- aerosole
TB drug resistance: resistant to one or more of first line drugs: isoniazid, rifampin, pyrazinamide and ethambutol (~ 5% in Canada)
MDR-TB: resistance to at least INH and rifampin (~ 0.7% in Canada)
XDR-TB: resistance to all first line therapeutic drugs (rare)
Diagnostic Testing
Culture is still the recommended method for diagnosing TB
Detection of AFB in respiratory secretionsChest X-rayTuberculin skin test (TST)Molecular diagnostic tests
procedure
Pulmonary or extra pulmonary samples are first decontaminated (NAL soln.)
Smear formation Inoculation to LJ and MGIT media.
Smear formation
After inoculation of specimen the MGIT are kept in bactec for 42 days
If any tube appears positive,It should be sub cultured, acid fast stained
and treated as presumptive positive
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