Pathophysiology: Totally drug-resistant tuberculosis (TDR-TB) is a generic term for tuberculosis strains that are resistant to a wider range of drugs than strains classified as Extensively drug-resistant tuberculosis. TDR-TB has been identified in three countries; India, Iran, and Italy. TDR-TB has resulted from further mutations within the bacterial genome to confer resistance, beyond those seen in XDR- and MDR-TB. Development of resistance is associated with poor management of cases.
Incidence of tuberculosis is the estimated number of new and relapse tuberculosis cases arising in a given year, expressed as the rate per 100,000 population. All forms of TB are included, including cases in people living with HIV. In Spain the incidence of Tuberculosis reported from 2001-2005 is 16 cases, and from 2006-2011 is also reported as 14 cases and in 2015 the cases wetre reported as 13 cases.
The principles of treatment for MDR-TB and for XDR-TB are the same. Treatment requires extensive chemotherapy for up to two years. Second-line drugs are more toxic than the standard anti-TB regimen and can cause a range of serious side-effects including hepatitis, depression, hallucinations, and deafness. Patients are often hospitalized for long periods, in isolation. In addition, second-line drugs are extremely expensive compared with the cost of drugs for standard TB treatment.
In the diagnostics pipeline, tests based on molecular technologies are the most advanced. A diagnostic platform called the GeneXpert Omni® is in development. It is intended for point-of-care testing for TB and rifampicin-resistant TB using Xpert MTB/RIF cartridges. The device is expected to be smaller, lighter and less expensive than currently available platforms for point-of-care nucleic acid detection and will come with a built-in, 4-hour battery. WHO expects to evaluate the platform in 2016.