Final answer:
The cotreatment of septic Enterococcus infections with vancomycin and an amino glycoside is an example of synergism, where the combined effect of drugs is greater than each drug's individual effect.
Step-by-step explanation:
The cotreatment of septic Enterococcus infections with vancomycin and an amino glycoside is an example of antibiotic synergism. This situation describes the use of two drugs that, when used together, provide a greater effect than the sum of their individual effects. Such synergistic combinations are commonly used to enhance the efficacy of treatment, particularly in severe infections like those caused by Enterococci.
On the other hand, antagonistic interactions between drugs cause a decrease in the efficacy of one or both drugs, which can be harmful to the patient. For instance, antimicrobial activity can be negatively impacted if a patient takes antacids that increase the pH of the stomach and interfere with the absorption of certain antibiotics.
Vancomycin's role as a last-line defense against resistant infections underscores the importance of preserving its efficacy through appropriate use, including the practice of combining it with other drugs for a synergistic effect.