Skip main navigation

Defining Gram-Negative Bacteria

Article introducing what gram negative bacteria (GNB) are.
Colourful figures sitting in a circle around a black question mark
© BSAC

Gram negative bacteria (GNB) are a large group of bacteria that do not retain the crystal violet stain used in the Gram staining method.

The Gram staining method was a basic approach invented at the end of the 19th century to try to distinguish one bacterium from another, according to the chemical and physical properties of their cell walls. This includes detecting the presence (gram-positive) or absence (gram-negative) of peptidoglycan in the bacterial outer layer.

[image]

There are many different species of Gram Negative bacteria, some are disease causing and some are not. One example of a large GNB family are Enterobacteriaceae – some, such as Proteus spp. and Enterobacter spp. can colonise our gastrointestinal tract without causing disease in some circumstances, but in others they can cause infections. However, others such as Salmonella spp. and Shigella spp. tend to cause disease.

If you wish to learn more about Gram-negative bacteria generally, take the Challenges in Antibiotic Resistance: Gram Negative Bacteria course.

This course will focus on a specific subset of GNB known as ‘non-fermenting Gram negative bacteria’ (which we will refer to as non-fermenters or NF). We will define what is meant by this in the next step.

© BSAC
This article is from the free online

Challenges in Antibiotic Resistance: Non-Fermenting Gram Negative Bacteria

Created by
FutureLearn - Learning For Life

Our purpose is to transform access to education.

We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.

We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.

Learn more about how FutureLearn is transforming access to education