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After the Ziehl-Neelsen staining procedure using carbol fuchsin, acid-fast bacteria are observable as vivid red or pink rods set against a blue or green background, depending on the specific counterstain used, such as methylene blue or malachite green, respectively. Non-acid-fast bacteria and other cellular structures will be colored by the ...
The pH indicator Methyl Red is added to one tube and a red color appears at pH's lower than 4.2, indicating a positive test (mixed acid fermentation is used). The solution remaining yellow (pH = 6.2 or above) indicates a negative test, meaning the butanediol fermentation is used.
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]
[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 Ziehl–Neelsen stain is an acid-fast stain used to stain species of Mycobacterium tuberculosis that do not stain with the standard laboratory staining procedures such as Gram staining. This stain is performed through the use of both red coloured carbol fuchsin that stains the bacteria and a counter stain such as methylene blue .
API 20NE rapid test system, one day after sample application. An analytical profile index is a fast identification system based on biochemical incubation tests. Usually, this test is used to quickly diagnose clinically relevant bacteria by allowing physicians to run about 20 tests at one time. [19]
The dip slide test consists of a sterile culture medium on a plastic carrier that is dipped into the liquid to be sampled. [3] The culture is then incubated, allowing for microbial growth. [ 2 ] Most Dip slides consist of 1 - 2 agars attached to a flexible plastic paddle, this allows full contact of the agar onto the desired area for testing. [ 4 ]
The Neogen Petrifilm plate is an all-in-one plating system made by the Food Safety Division of the Neogen Corporation.They are heavily used in many microbiology-related industries and fields to culture various micro-organisms and are meant to be a more efficient method for detection and enumeration compared to conventional plating techniques.