The following is a copy of a posting from Tiel Chat by Mary W. of Miami, which gives a good description of how a gram stain is done. Most gram stains can be done within minutes and usually at a very inexpensive cost while you are at the vet’s office.
Actually, to do a gram stain all they need from your bird is a sample of the material that they want to stain, to look for bacteria. This may be a poop, which you can scoop off the paper under the cage, or that the vet can scoop off the paper in the carrier, if you are bringing the bird to the vet for a visit. It just needs to be fresh enough to spread thinly on a glass slide. If the vet wants a stain of another area, such as the pharynx, or the cloaca (to see what type of bacteria are there), then he/she would use a teeny little swab and collect enough material from these areas, to spread on the glass slide for staining.
Maybe you know this already, but a gram stain is a stain that is done on a specimen, which will show the presence of bacteria, and the types of bacteria which can be categorized by their shape, and what color they stain with the grain stain. There are "gram positive" bacteria, which take on, and retain the primary stain, crystal violet and stain a blue-purple color, which can be seen under the microscope. Then there are "gram negative" bacteria, which take the crystal violet too, but allow this primary stain to be washed out in a "decolorizing" step using acetone. These bacteria take on the color of a secondary stain, safranin, a red stain which is added after decolorization so you can see them under the microscope too. These show up as red bacteria. You can see the shapes of these bacteria, usually as round, or "cocci", rods (long, or short rods, depending on the species), and spiril (cork-screwed or curved).
The shapes and the color: gram positive (blue) or gram negative (red) give the vet an idea of the types of bacteria present in the sample. But he can't tell the species of bacteria from the gram stain, since bacteria from many species look alike on a grain stain. For that he would need a culture, which will allow the bacteria to be isolated and identified.
In birds, the primary "normal flora" (bacteria), which are present in the respiratory, and GI tract, are in the "gram positive" category, such as "Lactobacillus" and "diptheroids", (these are also present on the skin and on mucus membranes of people too), these are rod shaped. The Staph species, (other than aureus) and Streptococcus spp (not Group A) are also normal and are "gram positive cocci". Usually when a vet wants a gram stain he's looking to see if there are "gram negative rods" present, and in what numbers. These can be pathogenic (cause infections in birds) and if they are seen in significant numbers in a bird poop, a cloacal or respiratory swab, then the vet would want to do a culture to see what the grain negative rod he's seeing under the microscope actually is. Well, hope this answers your question, and good luck with your bird.
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