A 50-year-old man presents with malaise, haemoptysis, and fever. He is homeless with a history of prior TB treatment completed 5 years ago. Sputum smear is AFB positive (2+). GeneXpert MTB/RIF shows MTB detected with rifampicin resistance. The next step is:
- A Send sputum for culture and drug sensitivity testing (DST) for all first and second-line drugs and commence pre-XDR-TB/MDR-TB regimen per national guidelines ✓
- B Restart standard HRZE regimen as the prior course may not have been completed properly
- C Treat with rifabutin as a substitute for rifampicin
- D Start fluoroquinolone monotherapy and await culture results
Correct answer: A. Send sputum for culture and drug sensitivity testing (DST) for all first and second-line drugs and commence pre-XDR-TB/MDR-TB regimen per national guidelines
Explanation
Rifampicin resistance on GeneXpert is a proxy marker for MDR-TB (resistant to at least isoniazid and rifampicin). Standard HRZE is contraindicated. Per WHO/RNTCP guidelines, extended DST (including fluoroquinolone and second-line injectable susceptibility) should be sent, and the patient enrolled in the appropriate MDR-TB or pre-XDR-TB regimen (BPaL-M or BPaLM regimen with bedaquiline, pretomanid, linezolid, ± moxifloxacin). Fluoroquinolone monotherapy would drive resistance.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.