Fecal samples were smeared onto glass microscope slides, heat fixed, and stained with Gram's stain (Jorgensen Laboratories, Loveland, CO, USA) on the day of collection.
Gram's stains also provided the opportunity to re-evaluate slides multiple times, if necessary.
Additionally, Gram's stain is a key identifier of isolates grown on culture media.
The conventional method for performing Gram's stain begins with a thin, air-dried, heat-fixed preparation on a glass slide that is flooded with crystal violet and allowed to sit for at least 30 seconds (see Table 1, above).
The American Society for Microbiology (ASM) provides a comprehensive summary of expected Gram's stain results and the morphologies of different organisms.
Recently, it has been suggested that an organism's reaction in Gram's stain is not strictly a result of the chemical composition of its cell wall, but rather is directly related to cell wall thickness.
13) However, one disadvantage of using Gram's stains to evaluate apparently healthy birds is that Gram's stain results and clinical health or disease are not always in good agreement.
Sample material from each swab was then transferred directly to a microscope slide for a Gram's stain or used to inoculate sheep's blood and MacConkey agar plates for culture.
Attempts were made to differentiate each bacterial isolate to the species level, although, in some cases, the organisms could be categorized only to the generic level of Gram's stain morphologic features.
Weaning birds may receive a Gram's stain of a crop wash.
We still recommend a fecal Gram's stain and fecal direct microscopic exam for most patients.
In general, for young birds presented to me for a postpurchase or first-time examination, I recommend baseline health laboratory work, including a CBC, biochemistry profile, liver function testing (bile acids), crop and fecal Gram's stain, and infectious disease screening.