====== Gram stain ======


[[Gram]] stain or Gram staining, also called Gram's method, is a method of staining used to distinguish and classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique.
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In Gram staining, the outer lipid-based membrane of gram-negative bacteria is removed by an alcohol solution. The alcohol also decolorizes the then exposed peptidoglycan layer by dissolving away the previously applied crystal violet. A counterstain (safranin or fuchsine) is then added which recolorizes the bacteria red or pink.

see [[Gram-positive bacteria]]

see [[Gram negative bacteria]]

A study demonstrates that while very specific for [[infection]], the [[sensitivity]] of intraoperative Gram staining is low, and agreement between positive cultures and Gram stains is very poor. Gram staining demonstrated limited cost-effectiveness because of the low prevalence of findings that altered patient management
((Shifflett GD, Nwachukwu BU, Bjerke-Kroll BT, Kueper J, Koltsov JB, Sama AA,
Girardi FP, Cammisa FP, Hughes AP. The value of intraoperative Gram stain in
revision spine surgery. Spine J. 2015 Oct 1;15(10):2198-205. doi:
10.1016/j.spinee.2015.06.001. Epub 2015 Jun 10. PubMed PMID: 26070285.)).