Did you know that there are two main types of bacteria? Gram-positive and gram-negative bacteria differ in their cell wall composition, which affects how they respond to antibiotics. The names "gram-positive" and "gram-negative" date back to 1884, when Hans Christian Gram developed a staining procedure. Researchers have found that both classes of bacteria share strategies for resisting antibiotics, but gram-negative bacteria have an edge due to their double membranes.

Source: https://www.livescience.com/health/viruses-infections-disease/what-s-the-difference-between-gram-positive-and-gram-negative-bacteria