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[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 ...
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 ...
Characterizes bacteria in one of two groups, Gram positive or Gram negative Gram positive appears purple in color Gram negative appears pink in color 4 Acid fast (Ziehl-Neelsen technique) Film stained with hot Z.N.C.F. decolourised (acid-alcohol) and counter stain with methylene blue Separate non-decolorized acid fast bacteria that are not ...
Some bacteria have cell walls which are particularly adept at retaining stains. These will appear positive by Gram stain even though they are not closely related to other gram-positive bacteria. These are called acid-fast bacteria, and can only be differentiated from other gram-positive bacteria by special staining procedures. [25]
The Kinyoun method can be modified as a weak acid fast stain, which uses 0.5–1.0% sulfuric acid instead of hydrochloric acid.The weak acid fast stain, in addition to staining Mycobacteria, will also stain organisms that are not able to maintain the carbol fuchsin after decolorizing with HCl, such as Nocardia species and Cryptosporidium.
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 ...
The genus is acid-fast to some degree, it stains only weakly Gram positive. The most common form of human nocardial disease is a slowly progressive pneumonia, the common symptoms of which include cough, dyspnea (shortness of breath), and fever. It is not uncommon for this infection to spread to the pleura or chest wall.
The Mycobacteria (acid-fast bacteria) have a cell envelope which is not typical of Gram-positives or Gram-negatives. The mycobacterial cell envelope does not consist of the outer membrane characteristic of Gram-negatives, but has a significant peptidoglycan-arabinogalactan-mycolic acid wall structure which provides an external permeability barrier.