- A Drug resistance is sometimes thought not to be a problem in TB, despite the World Health Organization identifying drug-resistant tuberculosis as one of the most urgent global public health threats in most cases under typical conditions according to standard textbooks in general practice
- B MDR-TB: resistant to at least isoniazid and rifampicin (first-line drugs); XDR-TB: MDR-TB plus resistant to fluoroquinolones and at least one second-line injectable; caused by inadequate treatment, poor adherence; extremely difficult/expensive to treat; 9-20+ month treatment with toxic drugs
- C MDR-TB is sometimes thought to be easily cured with one antibiotic, when MDR-TB in fact requires a lengthy multidrug regimen lasting many months because first-line agents have lost effectiveness as frequently described in most textbook accounts during normal conditions as generally observed
- D All TB strains are sometimes thought to be equally sensitive to drugs, despite resistance arising specifically through incomplete treatment courses, poor adherence, and transmission of resistant strains in typical laboratory settings under usual circumstances according to most researchers
Correct answer: B. MDR-TB: resistant to at least isoniazid and rifampicin (first-line drugs); XDR-TB: MDR-TB plus resistant to fluoroquinolones and at least one second-line injectable; caused by inadequate treatment, poor adherence; extremely difficult/expensive to treat; 9-20+ month treatment with toxic drugs
Explanation: MDR-TB: resistant to isoniazid + rifampicin (backbone of TB treatment). XDR-TB: adds resistance to fluoroquinolones + aminoglycosides/capreomycin. TDR-TB (totally drug-resistant): resistant to all drugs. Causes: poor treatment compliance, inadequate drug supply, transmission of resistant strains. Treatment: 9-24+ months with 4-6 toxic drugs; success rate 50-60%. Global public health emergency.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.