Drug resistance is said to occur when TB organisms continue to grow in the presence of one or more anti-TB
- Although several factors can contribute to the development of drug-resistant TB, inadequate anti-TB
treatment is probably the most important. Inadequate anti-TB treatment leads to mutation in drug-susceptibility
bacilli making them drug resistant.
Risk factors for drug-resistant TB are:
- Chronic cases (still sputum smear-positive after completing a supervised retreatment regimen)
- Contact with known drug-resistant tuberculosis
- Retreatments (relapses, treatment after failures, return after loss to follow-up)
- History of frequent interruption of drug treatment
- HIV-positive patient presumed to have TB
- Patients who remain sputum smear-positive at month 2 or 3 of first-line anti-TB treatment
- Health care workers
- Patients from prisons or other congregate settings
Patients suspected to have DR-TB should be screened using rapid drug susceptibility testing (DST) of rifampicin
- All patients who are drug-resistant TB suspects should therefore have sputum/other specimens taken for culture
and DST in vivo.
Patients with drug-resistant TB should be treated at specialised centers with approved regimens.
DRUG RESISTANT TB IS A MAJOR PUBLIC HEALTH PROBLEM. INADEQUATE TB TREATMENT IS THE
MAJOR CONTRIBUTING FACTOR!