Gram-negative

American  

[gram-neg-uh-tiv] / ˈgræmˈnɛg ə tɪv /

adjective

(often lowercase)

1. (of bacteria) not retaining the violet dye when stained by Gram's method.

---

Gram-negative British  

adjective

1. designating bacteria that fail to retain the violet stain in Gram's method

---

gram-negative Scientific  

1. Relating to a group of bacteria that do not change color when subjected to the laboratory staining method known as Gram's method or Gram's stain. 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.

2. Compare gram-positive

---

Etymology

Origin of Gram-negative

First recorded in 1905–10; Gram's method

Example Sentences

He will be targeting AI at a tricky group of infections, called Gram-negative bacteria, that includes well known bugs such as E. coli and Klebsiella pneumoniae.

From BBC

Treating carbapenem-resistant Gram-negative bacterial infections is doubly difficult because those bacteria are resistant to some of the most powerful antibiotics.

From BBC

Gram-negative bacteria have a double layer of protection, making them more difficult to kill, Muñoz said.

From Science Daily

Fusobacterium is a Gram-negative microbe found in the GI tract and the oral cavity, and previous studies have connected it to the development of CRC.

From Science Daily

A new medicine capable of combating Gram-negative bacteria, a particularly hardy type of bug with inner and outer membranes that antibiotics struggle to cross, hasn’t hit the market in 50 years.

From Los Angeles Times