Medical Definition of Gram-negative. This is characteristic of bacteria that have a cell wall composed of a thin layer of a particular substance (called peptidoglycan). The Gram-negative bacteria include most of the bacteria normally found in the gastrointestinal tract that can be responsible for disease as well as gonococci (venereal disease)
Gram-negative. Refers to the property of many bacteria that causes them to not take up color with Gram’s stain, a method which is used to identify bacteria. Gram-positive bacteria which take up the stain turn purple, while Gram-negative bacteria which do not …
Gram-negative bacteria have relatively thin cell walls and are generally resistant to the effects of antibiotics or the actions of the body’s immune cells. Gram-negative bacteria include E. coli and the bacteria that cause gonorrhea, typhoid fever, rickettsial fever, cholera, syphilis, plague, and Lyme disease. gram-positive.
Definition of gram-negative. : not holding the purple dye when stained by Gram’s stain —used chiefly of bacteria.
(of bacteria) not retaining the violet dye when stained by Gram’s method. gram-negative. Relating to a group of bacteria that generally are resistant to the effects of …
Gram-negative: Gram-negative bacteria lose the crystal violet stain (and take the color of the red counterstain) in Gram’s method of staining. This is characteristic of bacteria that have a cell wall composed of a thin layer of a particular substance (called peptidoglycan).
home / medterms medical dictionary a-z list / gram-positive definition. Gram-positive: Gram-positive bacteria retain the color of the crystal violet stain in the Gram stain. This is characteristic of bacteria that have a cell wall composed of a thick layer of a particular substance (called peptidologlycan).
General Information About Gram-Negative Bacteria
Characteristics. Gram-negative bacteria’s S-layer is attached directly to the outer membrane ). Specific to Gram-positive bacteria is the presence of teichoic acids in the cell wall. Some of these are lipoteichoic acids, which have a lipid component in the cell membrane that can assist in anchoring the peptidoglycan.
The main difference between gram positive and gram negative bacteria is that gram positive bacteria contain a thick peptidoglycan cell wall along with teichoic acid, allowing the bacteria to stain in purple during gram staining whereas gram negative bacteria contain a thin peptidoglycan cell wall with no teichoic acid, allowing the cell wall to
Basically, gram-positive bacteria are those that appear violet or bluish under the microscope whereas gram-negative bacteria are those that appear pink. Initially, all bacteria in a bacterial smear on the slide are stained violet.