Antibiotic Resistance
Skin infections are usually treated empirically; however, because of widespread bacterial resistance, determining bacterial susceptibility to an antibiotic agent is becoming essential to treatment. If a bacterial isolate is determined to be resistant to a given antibiotic agent, the agent cannot be used in treatment; determining susceptibility to an antibiotic agent does not always guarantee an effective treatment. When a single mechanism confers resistance to multiple antibiotic agents, it is known as cross resistance. Antibiotic agents that are closely related commonly exhibit cross resistance.
There are four mechanisms by which antibiotic resistance can be established:
- Altered permeability of the antimicrobial agent—the agent is no longer able to enter the bacterial cell
- Inactivation of the antimicrobial agent, frequently the result of the production of an enzyme
- Altered target site on the bacteria
- Replacement of a sensitive pathway, the bacterium can acquire a new enzyme to replace the sensitive one
Bacterial resistance and antibiotic cross resistance become more and more widespread. It has become more important for doctors to determine susceptibility and resistance to antibiotic agents in the course of treating an infection; and even more important for researchers to develop new and more powerful classes of antibiotics to prevent and treat these infections.
