Search results
Results from the WOW.Com Content Network
[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 ...
Mechanism of acid-fast staining in acid-fast cells and non-acid-fast cell [23] [24] [25] 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.
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.
Mycobacterium tuberculosis (M. tb), also known as Koch's bacillus, is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. [ 1 ] [ 2 ] First discovered in 1882 by Robert Koch , M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid .
Mycobacterium smegmatis is an acid-fast bacterial species in the phylum Actinomycetota and the genus Mycobacterium. It is 3.0 to 5.0 μm long with a bacillus shape and can be stained by Ziehl–Neelsen method and the auramine-rhodamine fluorescent method.
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 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 ...
Since MTB retains certain stains even after being treated with acidic solution, it is classified as an acid-fast bacillus. [14] [58] The most common acid-fast staining techniques are the Ziehl–Neelsen stain [60] and the Kinyoun stain, which dye acid-fast bacilli a bright red that stands out against a blue background. [61]