Final answer:
Trophile testing is used before starting HIV treatment with CCR5 antagonists to determine the strain's tropism, essential for medication effectiveness. Additional diagnostic tests like viral titer and CD4 count assist in treatment planning. The Kirby-Bauer assay aids in predicting antibiotic efficacy against specific pathogens.
Step-by-step explanation:
The medication that requires trophile testing to determine the patient's tropism before starting is typically associated with HIV treatment. Tropism testing, such as a trofile test, is used to determine if the patient's HIV strain is CCR5-tropic, CXCR4-tropic, or dual/mixed-tropic, which influences the choice of certain antiretroviral therapy (ART). The test is crucial before starting CCR5 antagonists such as maraviroc, as this medication is only effective against CCR5-tropic strains.
Additional tests that should be performed on the patient to determine suitable treatment can include a viral titer to assess the concentration of virus present, CD4 cell count to evaluate immune function, and resistance testing to inform on potential effectiveness of specific antiretroviral drugs. Based on these results, the doctor can recommend a tailored ART regimen.
In another context, the Kirby-Bauer assay is used to predict the therapeutic effectiveness of an antimicrobial drug in a patient. This involves measuring the zone of inhibition around antibiotic-impregnated disks on an agar plate inoculated with the pathogen of interest. According to the results, a physician can determine whether the pathogen is susceptible, intermediate, or resistant to the antibiotic tested, supporting the selection of an effective treatment.