High levels of antibiotic can be maintained in the bodies of patients long enough to kill all pathogens, including resistant mutants or to inhibit them so that body defenses can kill them. 13.8 for an illustration of the effects of premature termination of antibiotic treatment. In the following example, another antibiotic is added to penicillin to increase its effectiveness. Clavulanic acid binds to beta lactamases and prevents them from inactivating the amoxicillin. There are many different kinds of infectious agents in confined area.
Sick people live in close proximity.
Hospitalized patients tend to be more severely ill and many have lowered resistance to infections because of their illness or because they are taking immunosuppressant drugs. A bacteria is uniformly spread over an agar plate. Filter paper disks are saturated with the drug and placed on the agar surface . Clear areas called zones of inhibition appear on the agar as round disks where the drugs inhibit the bacteria. Metabolic processes in a living organism may inactivate or inhibit a drug.