Tuberculosis is an extremely contagious and dangerous disease, and there is a good chance that you and other people in your office could have been infected by the bacteria. Since someone in your office had a full blown tuberculosis infection, many of you would have been exposed to the infection for several hours a day over a period of several days, and probably several weeks. Therefore, it is probably a good idea for you and the rest of the staff in your office to undergo treatment, especially if your health authorities think that this is necessary. It is not uncommon for people who are regularly in contact with a tuberculosis patient to be treated for the disease as well, even before the former show any signs of the disease.
Very often, a tuberculosis infection remains latent for a long period of time, and therefore asymptomatic. A large number of these cases eventually turn into full blown tuberculosis infections, and it is therefore advisable to fight the infection right from the start. Generally speaking, it is of course not advisable to take antibiotics before you even get sick, but in this case there is no other choice. Vaccination is usually a better option rather than taking antibiotics as a precautionary measure, but unfortunately, we have so far been unable to develop a tuberculosis vaccine for adults. As of now only children can be vaccinated against tuberculosis.
Part of the problem with tuberculosis is that tests to detect the disease are not a hundred per cent reliable - tests for tuberculosis are known to produce false negatives. Therefore the fact that your test results are entirely normal is not necessarily proof that you do not have a latent tuberculosis infection. Besides this fact, the skin test and x ray that you mention are only two ways in which it is possible to test for tuberculosis. If you want to do a complete, exhaustive check for whether you have tuberculosis, you need to visit a doctor, who will perform a full physical check up, examine your medical history, and take blood samples to perform microbiological tests, besides performing the chest x ray and the tuberculin skin test.
However, as mentioned, this does not entirely rule out an infection. For someone who has been exposed to tuberculosis for a long time, there is a high risk of infection, and it is safer to get yourself treated.
answered by G M