What is the exact technical difference between multi drug resistant TB and extensively drug resistant (XDR) TB?
Multi-drug resistant TB (MDR-TB) is an isolate of Mycobacterium tuberculosis that is found to be resistant to at least rifampicin and isoniazid. Extensively drug resistant TB (XDR-TB) is a sub-type of MDR TB. XDR TB is an isolate of Mycobacterium tuberculosis that is found to be multi-drug resistant (i.e. MDR-TB), which is also resistant to any fluoroquinolone and at least 1 of the 3 injectable second-line drugs (capreomycin, kanamycin or amikacin). All drug-resistance in tuberculosis is man-made, caused by inappropriate use of anti-TB drugs. That means providers who use non-standard regimens, prescribe non-quality assured drugs, make patients pay for drugs which they may not be able to afford, and provide treatment without ensuring patient adherence through supportive supervision. The laboratory tests required for the detection of drug resistance, which are culture and drug susceptibility testing (DST), are technically complicated, and therefore any laboratory undertaking drug sensiti
