State why antimicrobial susceptibility testing is often essential in choosing the proper chemotherapeutic agent to use in treating and infection.
For some microorganisms, susceptibility to chemotherapeutic agents is predictable. For many other microorganisms (Pseudomonas, Staphylococcus aureus, G- enteric bacilli like E. coli, Serratia, Proteus, etc.) there is no reliable way of predicting which antimicrobial agent will be effective, especially with the emergence of antibiotic-resistant strains of bacteria. Because of this antimicrobial susceptibility testing is essential to determine which antimicrobial agent to use against a specific strain of bacterium.