Extensively Drug-Resistant Tuberculosis (Xdr-Tb): Successful Therapies Used in the Clinic to the Disease

Mycobacterial species have practically evolved along humankind, sometimes provoking serious diseases. Among them, tuberculosis (TB), produced by M. tuberculosis-complex bacteria, is historically the single most devastating infectious agent. Like many other microorganisms, M. tuberculosis resistant to antibiotics have risen as a consequence of selective pressure for mutants able to persist despite being attacked with drugs that would otherwise erradicate them from the infected person. Given the current long-term (6-9 months) therapy with multiple antibiotics, many people abandon their treatments, therefore promoting that bacteria that were not eliminated during therapy get exposed to suboptimal antibiotic concentrations, probably leading to mutations and drug resistance. In this scenario, extremely-drug resistant (XDR) TB was recognized not more than a decade ago, prompting concerns for a more complicated drug regimen with few available molecules. In recent years, either old antibiotics have been rediscovered as good measures to control XDR-TB, or new ones have emerged as alternatives to cure patients of this type of infection. In this work we aim to provide the medical community in Mexico with information of such drug regimens that have succesfully worked, in order to get their consideration for use in our country.