Drug resistance mechanisms?

Question

Give an example of each of the following regarding drug resistance mechanisms:

-enzymatic inactivation

-modification of target

-active efflux

also, what is active efflux?

thanks

Answer 1

An example of enzymatic inactivation would be how strains of some Gram-negative bacteria like Haemophilus influenzae and Staphylococcus aureus produce enzymes that open the beta-lactam ring, which is a component of penicillins and cephalosporins, thus rendering the antibiotics incapable of binding to their targets.

An example of modification of target is the way drug-resistant strep (Streptococcus pneumoniae) strains alter the penicillin-binding proteins on their surfaces, so that the drug no-longer "recognizes" them.

Active efflux is when a bacterium develops a mechanism that actually expels an antibiotic.  For example, some strains of E. coli have a set of proteins that act as an "efflux pump" to expel tetracyclines, and some S. pneumoniae can similarly expel Clindamycin.