[Tuberculosis 110 years after the Nobel Prize awarded to Koch]

The Nobel Prize in Physiology or Medicine was awarded in 1905 to Robert Koch "for his investigations and discoveries in relation to tuberculosis (TB)". He discovered the causal agent of TB, described the four principles that since then have guided research in communicable diseases and also prepared the old tuberculin, a bacillary extract that failed as a healing element but allowed the early diagnosis of TB infection and promoted the understanding of cellular immunity. After his death, the most conspicuous achievements against TB were the BCG vaccine, and the discovery of streptomycin, the antibiotic that launched the era of the effective treatment of TB. Drug-resistance soon appeared. In Argentina, studies on drug resistance began in the 60s. In the 70s, shortened anti-TB drug schemes were introduced consisting in two-month treatment with four drugs, followed by four months with two drugs. The incidence of TB decreased worldwide, but the immune depression associated with awarded together with the misuse of anti-TB drugs allowed the emergence of multidrug resistance and extensive resistance, with the emergence of nosocomial outbreaks worldwide, including Argentina. New rapid diagnostic methods based on molecular biology were developed and also new drugs, but the treatment of multidrug resistant and extensively resistant TB is still difficult and expensive. TB research has marked several milestones in medical sciences, including the monumental Koch postulates, the tuberculin skin test that laid the basis for understanding cell-mediated immunity, the first design of randomized clinical trials and the use of combined multi-drug treatments.