I am not convinced that your fish have TB, the curvature of the spine is something that develops gradually over a period of time as well as other skeletal deformities, not from one day to another! There are many other symptoms with TB, like loss of appetite, loss of scales, black spots, skin ulcers, bleedings....
The best treatment of TB is euthanasia, desinfecting your tank and to start over!
In my opinion you should be more worried about the levels of the ammonia in your tank. Even prolongued exposure to low levels of ammonia can cause permanent damage to your fish. Ammonia is irritating to their skin, and especially their gills. Ammonia can cause organ damage and death!!!
It is still quite possible that your tank is infected with some sort of disease. Have you looked for any signs of parasites on your fish? Are there any stringy things hanging off of them, either from their gills, or their anus? Some parasites could also be internal, and there are many that are difficult to treat.
But before I would go out and invest in all kinds of expensive medications, I would try to elliminate the more simple possible causes first, and in your case that would be the readings of ammonia! The readings of ammonia could also have weakened their immunesystem and made them more susceptible for some infection they would normally be able to fight off. I don't know!
Maybe someone with more knowledge will come by and give you more or better answers, but that's my 2 cents on this!