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Gram staining is a bacteriological laboratory technique [8] used to differentiate bacterial species into two large groups (gram-positive and gram-negative) based on the physical properties of their cell walls. [9] [page needed] Gram staining can also be used to diagnose a fungal infection. [1]
The spot indole test is used to determine if a microbe can deaminate tryptophan to produce indole. This test is performed by saturating a piece of filter paper with Indole Kovacs Reagent and scraping a portion of microbe onto the paper. A color to a pink-red color indicates a positive result while no color change indicates the lack of ...
A laboratory specimen is sometimes a biological specimen of a medical patient's tissue, fluids, or other samples used for laboratory analysis to assist in differential diagnosis or staging of a disease process. These specimens are often the most reliable method of diagnosis, depending on the ailment.
Examining colonial morphology is the first step in the identification of an unknown microbe. The systematic assessment of the colonies' appearance, focusing on aspects like size, shape, colour, opacity, and consistency, provides clues to the identity of the organism, allowing microbiologists to select appropriate tests to provide a definitive ...
When starch is mixed with iodine in solution, an intensely dark blue colour develops, representing a starch/iodine complex. Starch is a substance common to most plant cells and so a weak iodine solution will stain starch present in the cells. Iodine is one component in the staining technique known as Gram staining, used in microbiology.
Ames test procedure. One classical bioassay is the Ames test. A strain of Salmonella that requires histidine to grow is put on two plates with growth medium containing minimal amounts of histidine and some rat liver extract (to mimick liver metabolism). A suspected mutagen is added to one plate. If the plate with the suspected mutagen grows ...
The sample probably is the substance. For example, the Kastle–Meyer test will show either that a sample is not blood or that the sample is probably blood, but may be a less common substance. Further chemical tests are needed to prove that the substance is blood. Confirmatory tests are the tests required to confirm the analysis. Confirmatory ...
Although antibiotic sensitivity testing is done in a laboratory , the information provided about this is often clinically relevant to the antibiotics in a person . [36] Sometimes, a decision must be made for some bacteria as to whether they are the cause of an infection, or simply commensal bacteria or contaminants, [ 28 ] such as ...