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The TSI slant is a test tube that contains agar, a pH-sensitive dye , 1% lactose, 1% sucrose, 0.1% glucose, [2] and sodium thiosulfate and ferrous sulfate or ferrous ammonium sulfate. All of these ingredients are mixed together, heated to sterility, and allowed to solidify in the test tube at a slanted angle.
A TSI slant is often used to distinguish nonfermenting Pseudomonas species from enteric pathogens in faecal specimens. [citation needed] When P. aeruginosa is isolated from a normally sterile site (blood, bone, deep collections), it is generally considered dangerous, and almost always requires treatment.
Shigella dysenteriae is a species of the rod-shaped bacterial genus Shigella. [1] Shigella species can cause shigellosis (bacillary dysentery). Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacteria. [2] S. dysenteriae has the ability to invade and replicate in various species of epithelial cells and ...
The triple sugar iron (TSI) test is a differential media used to tell whether an organism can ferment glucose, sucrose, and/or lactose and whether an organism can produce hydrogen sulfide gas. [ 36 ] Urea agar slant
Bacteria able to decarboxylate lysine will leave the media purple colored. Bacteria producing hydrogen sulfide will appear black. [1] A frequent test done with LIA agar is the LIA slant. Here the LIA is solidified at an angle, then inoculated with bacteria by stabbing the agar to within 1/4 inch of the bottom of the tube and streaking the slant ...
Although it could be used in other formats (e.g., Petri plates), Simmons' citrate agar is often used in slants or slopes in test tubes. One advantage of using slants over Petri dishes is access to oxygen, which is required by citrate metabolism. Simmons’ agar can be bought from suppliers as ready-made powders or slants.
Most gut bacteria, including Salmonella, can ferment the sugar xylose to produce acid; Shigella colonies cannot do this and therefore remain red. After exhausting the xylose supply Salmonella colonies will decarboxylate lysine, increasing the pH once again to alkaline and mimicking the red Shigella colonies.
Cetrimide also enhances the production of Pseudomonas pigments such as pyocyanin and pyoverdine, which show a characteristic blue-green and yellow-green colour, respectively. [ 3 ] [ 4 ] Cetrimide agar is widely used in the examination of cosmetics, pharmaceuticals and clinical specimens to test for the presence of Pseudomonas aeruginosa .