is HIV positive or not (HIV co-infection is associated with an increased mortality). Treatment courses are a minimum of 18 months and may last years; it may require surgery, though death rates remain high despite optimal treatment. That said, good outcomes are still possible. Treatment courses that are at least 18 months long and which have a directly observed component can increase cure rates to 69%. The treatment of MDR-TB must be undertaken by a physician experienced in the treatment of MDR-TB. Mortality and morbidity in patients treated in non-specialist centres is significantly elevated compared to those patients treated in specialist centres. In addition to the obvious risks (e.g., known exposure to a patient with MDR-TB), risk factors for MDR-TB include male sex, HIV infection, previous incarceration, failed TB treatment, failure to respond to standard TB treatment, and relapse following standard TB treatment. A large proportion of people with MDR-TB are unable to access treatment due to what Paul Farmer describes as an "Outcome Gap". The majority of people struck with MDR-TB live in "resource-poor settings" and are denied treatment because international organizations have refused to make technologies available to countries who cannot afford to pay for treatment, the reason being that second line drugs are to expensive therefore treatment methods for MDR-TB are not sustainable in impoverished nations. Farmer argues that this is social injustice and we cannot allow people to die simply because they are faced with circumstances where they cannot afford "effective therapy". Treatment of MDR-TB must be done on the basis of sensitivity testing: it is impossible to treat such patients without this information. If treating a patient with suspected MDR-TB, the patient should be started on SHREZ+MXF+cycloserine pending the result of laboratory sensitivity testing. A gene probe for rpoB is available in some countries and this serves as a useful marker for MDR-TB, because isolated RMP resistance is rare (except when patients have a history of being treated with rifampicin alone). If the results of a gene probe (rpoB) are known to be positive, then it is reasonable to omit RMP and to use SHEZ+MXF+cycloserine. The reason for maintaining the patient on INH despite the suspicion of MDR-TB is that INH is so potent in treating TB that it is foolish to omit it until there is microbiological proof that it is ineffective. There are also probes available for isoniazid-resistance (katG and mabA-inhA), but these