The ironic and tragic twist....
..is that, in order for drug resistant disease to exist, the bacillus has to be first exposed to the TB drugs that can kill it.
This is why the epidemic of drug resistance got off to a slow start in Africa (because these drugs were in such short supply), but is also why, with the imporved supply of the cheaper first line drugs the bacillus is playing catch-up with such a deadly vengeance.
The other requirement to foster drug-resistance is inadequate administration of the drugs themselves, and unfortunately, in most of Sub-Saharan Africa, you have this by the spadeful.
And in order to appropriately treat drug resistant TB, you don't just need the second line drugs, you also need the appropriate expensive diagnostic facilities because without them you simply cannot safely prescribe these drugs. Blood samples need to be cultured in order for a clinician to ascertain exactly which drugs the strain actually IS susceptible to. Such diagnostic facilities simply do not exist in most of Africa.
There have been reports of new diagnostic methods being developed (Xpert) that are both cheaper and much faster than the current culturing methods. Whilst this is very encouraging, our understanding is that their capacity to actually identify resistance to more than a single drug (rifampicin) is severely limited, meaning that clinicians are still unable to properly diagnose and treat MDR-TB as they need to.
The tragic irony is that those cheaper first line drugs, without being accompanied by a phalanx of medical infrastructure, are predictably promoting an epidemic of otherwise untreatable disease.