Gram-positive
adjective
(of bacteria) retaining the violet dye when stained by Gram's method.
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Gram-positive
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gram-positive
gram-positiveRelating to a group of bacteria that turn a dark-blue color when subjected to a laboratory staining method known as Gram's method. Gram-positive bacteria have relatively thick cell walls and are generally sensitive to the destructive effects of antibiotics or the actions of the body's immune cells. Gram-positive bacteria include beneficial nitrogen-fixing bacteria in soil, as well as the bacteria that cause anthrax, botulism, leprosy, tuberculosis, scarlet fever, and strep throat.
Gram-positive
American
[gram-poz-i-tiv]
/ ˈgræmˈpɒz ɪ tɪv /
adjective
(often lowercase)
Gram-positive
British
adjective
gram-positive
Scientific
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Relating to a group of bacteria that turn a dark-blue color when subjected to a laboratory staining method known as Gram's method. Gram-positive bacteria have relatively thick cell walls and are generally sensitive to the destructive effects of antibiotics or the actions of the body's immune cells. Gram-positive bacteria include beneficial nitrogen-fixing bacteria in soil, as well as the bacteria that cause anthrax, botulism, leprosy, tuberculosis, scarlet fever, and strep throat.
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Compare gram-negative
Etymology
Origin of Gram-positive
First recorded in 1905–10; see origin at Gram's method
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
She added that the drugs did not provide effective coverage against a Gram-positive organism, which was the most likely pathogen causing the infection.
From BBC ● Mar. 11, 2026
Gram-positive and gram-negative bacteria differ in the composition of their cell walls.
From Science Daily ● May 29, 2024
"We have pretty strong evidence that this new structural class is active against Gram-positive pathogens by selectively dissipating the proton motive force in bacteria," Wong says.
From Science Daily ● Dec. 21, 2023
In Gram-positive bacteria, lipoteichoic acid anchors the cell wall to the cell membrane.
From Textbooks ● Jan. 1, 2015
In the early stages of incubation, at 100° to 112° F., the bacilli are uniform in size and intensely Gram-positive; in succeeding stages the irregular, vacuolated, inflated, and ruptured forms predominate.
From The Bacillus of Long Life a manual of the preparation and souring of milk for dietary purposes, together with and historical account of the use of fermente by Loudon Douglas
"Most clinically approved antibiotics only kill gram-positive bacteria or kill both gram-positive and gram-negative bacteria," Muñoz said.
From Science Daily ● May 29, 2024
The experimental dressing had excellent antibacterial performance against gram-negative and gram-positive bacterial species, and effectively eradicated E. coli and staph bacteria in testing.
From Science Daily ● Feb. 8, 2024
During the production of yogurt and wine, which rely on gram-positive bacteria, the pH is controlled.
From Textbooks ● Jun. 9, 2022
Explain why homeostasis for gram-positive bacteria requires control of extracellular pH.
From Textbooks ● Jun. 9, 2022
The protective value of both "gram-positive" and "gram-negative" destroyers has yet to be tried on human beings.
From Time Magazine Archive
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
