Chapter 2.2, Problem 2MM

Medical Moment

Gram-Positive Versus Gram-Negative Bacteria

The Gram slain is one type of differential stain that can help to identify bacterial species and guide treatment decisions. Differentiating between gram-positive and gram-negative organisms is important. One of the main differences between gram-positive and gram-negative bacteria is that gram-negative bacteria have an outer membrane containing LPS (lipopolysaccharide). This molecule is also called endotoxin, which can cause a severe reaction if it enters the circulatory system, causing symptoms of shock (high fever, dangerously low blood pressure, and elevated respiratory rate). This is known as endotoxic shock.

Q. This molecule has two names: lipopolysaccharide and endotoxin. Which of these is most often used by medical doctors and which is more likely to be used by microbiology researchers?