2.1 Intrinsic resistance

Intrinsic resistance is the innate ability of a type of bacteria species to resist the action of an antibiotic as a consequence of the bacteria’s structural or functional characteristics. In contrast to acquired resistance, which you will look at next, intrinsic resistance is ‘normal’ for bacteria of a given type.

Intrinsic resistance may occur because bacteria lack the target for a particular antibiotic or because the drug can’t get to its target. It reduces the pool of antibiotics available to treat infections. In addition, as you will see in Week 4, resistance elements that are intrinsic to one bacterial type can be transferred to another one. In this way, intrinsic antibiotic resistance in non-pathogenic bacteria (like the ones you saw in Video 1) can be transferred to a pathogenic bacterium where it can restrict the treatment options for infections caused by these bacteria.