ANTIBIOTIC
RESISTANCE Overuse or misuse of
antibiotics has led to growing problems with resistance to antibiotics
in commonly encountered bacteria. The use of
antibiotics selects out resistant organisms by killing the nonresistant ones, leaving the resistant ones behind. However, the mechanism by which bacteria become resistant is very complex and not always understood. While
resistance correlates with use of a particular drug, there are several instances where organisms have become resistant to antibiotics that have not been used against them.
Organisms may be naturally resistant to an antibiotic, or resistance may be acquired. For example, enterococci are naturally resistant to cephalosporins, macrolides, and other types of antibiotics. Bacteria can acquire resistance via uptake of DNA material from other organisms or by unmasking portions of their own DNA. Infection with resistant bacteria is associated with higher illness and death rates. Because of the increase in resistant bacteria, appropriate antibiotic use is more critical now than ever before.