HIV Drug Resistance — SCE Infectious Diseases MCQ

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HardHIV MedicineHIV Drug ResistanceSCE Infectious Diseases

Genotypic resistance testing in a person with virological failure shows M184V and K103N. Which drug classes are primarily affected?

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Correct answer: D — M184V affects NRTIs; K103N affects NNRTIs

BHIVA recommends genotypic resistance testing during virological failure to guide the next regimen. M184V/I causes high-level resistance to lamivudine and emtricitabine, both NRTIs, while K103N is a classic NNRTI mutation affecting efavirenz and nevirapine. The original E138K item was ambiguous because E138K can occur in more than one resistance context; this pair tests unambiguous class mapping.

Reference: BHIVA HIV-1 treatment guidelines: 2025 interim update. https://bhiva.org/clinical-guideline/hiv-1-treatment-guidelines/ IAS–USA: 2025 HIV-1 drug-resistance mutations. https://www.iasusa.org/wp-content/uploads/2025/03/33-2-mutations.pdf