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The acid-fast staining method, in conjunction with auramine phenol staining, serves as the standard diagnostic tool and is widely accessible for rapidly diagnosing tuberculosis (caused by Mycobacterium tuberculosis) and other diseases caused by atypical mycobacteria, such as leprosy (caused by Mycobacterium leprae) and Mycobacterium avium ...
Acid-fast stains such as Ziehl–Neelsen, or fluorescent stains such as auramine are used instead to identify M. tuberculosis with a microscope. The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen. Primarily a pathogen of the mammalian respiratory system, it infects the lungs.
[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 ...
A diagnosis of TB should, however, be considered in those with signs of lung disease or constitutional symptoms lasting longer than two weeks. [100] A chest X-ray and multiple sputum cultures for acid-fast bacilli are typically part of the initial evaluation. [100]
They are characterized as Gram-positive, nonmotile, acid-fast, short to long rods. [citation needed] Colony characteristics. Usually, colonies are smooth, rarely rough, and not pigmented colonies. Older colonies may become yellow. Physiology. Growth on Löwenstein-Jensen medium and Middlebrook 7H10 agar occurs at 37°C after seven or more days.
The two most common methods for visualizing these acid-fast bacilli as bright red against a blue background are the Ziehl-Neelsen stain and modified Kinyoun stain. Fite's stain is used to color M. leprae cells as pink against a blue background. Rapid Modified Auramine O Fluorescent staining has specific binding to slowly-growing mycobacteria ...
Sputum smears and cultures should be done for acid-fast bacilli if the patient is producing sputum. [1] The preferred method for this is fluorescence microscopy (auramine-rhodamine staining), which is more sensitive than conventional Ziehl–Neelsen staining. [4]
The term "fast growing" is a reference to a growth rate of 3 or 4 days, when compared to other Mycobacteria that may take weeks to grow out on laboratory media. Pulmonary infections of M. fortuitum are uncommon, but Mycobacterium fortuitum can cause local skin disease, osteomyelitis (inflammation of the bone), joint infections and infections of ...