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The medical history includes obtaining the symptoms of pulmonary TB: productive, prolonged cough of three or more weeks, chest pain, and hemoptysis.Systemic symptoms include low grade remittent fever, chills, night sweats, appetite loss, weight loss, easy fatiguability, and production of sputum that starts out mucoid but changes to purulent. [1]
Since MTB retains certain stains even after being treated with acidic solution, it is classified as an acid-fast bacillus. [13] [57] The most common acid-fast staining techniques are the Ziehl–Neelsen stain [59] and the Kinyoun stain, which dye acid-fast bacilli a bright red that stands out against a blue background. [60]
Other bacteria are commonly identified with a microscope by staining them with Gram stain. However, the mycolic acid in the cell wall of M. tuberculosis does not absorb the stain. Instead, acid-fast stains such as Ziehl–Neelsen stain, or fluorescent stains such as auramine are used. [4]
Mechanism of acid-fast staining in acid-fast cells and non-acid-fast cell [24] [25] [26] The mechanism of action of the Ziehl-Neelsen stain is not completely understood, but it is thought to involve a chemical reaction between the acidic dyes and the cell walls of the bacteria .
[1] [2] Once stained as part of a sample, these organisms can resist the acid and/or ethanol-based decolorization procedures common in many staining protocols, hence the name acid-fast. [ 2 ] The mechanisms of acid-fastness vary by species although the most well-known example is in the genus Mycobacterium , which includes the species ...
Gram-positive, nonmotile and acid-fast rods (1-3 μm x 0.2-0.4 μm). Sometimes long rods with occasional beaded or swollen cells having non-acid-fast ovoid bodies at one end. Colony characteristics. Smooth hemispheric colonies, usually off-white or cream colored. May be butyrous, waxy, multilobate and even rosette clustered (dilute inocula).
The diagnosis is confirmed by finding acid-fast bacilli in a biopsy of the skin. [3] Leprosy is curable with multidrug therapy. [4] Treatment of paucibacillary leprosy is with the medications dapsone, rifampicin, and clofazimine for six months. [9] Treatment for multibacillary leprosy uses the same medications for 12 months. [9]
The two most common commercially available tests are the amplified mycobacterium tuberculosis direct test (MTD, Gen-Probe) and Amplicor. [15] In 2007, review concluded that for diagnosing tuberculous meningitis "Individually, the AMTD test appears to perform the best (sensitivity 74% and specificity 98%)", they found the pooled prevalence of TB ...