Of all the bacteria in existence, almost 99% are good, helpful bacteria. The other 1%, however, is harmful towards the body and can make you very sick, sometimes fatally ill.
One type of harmful bacteria is Tuberculosis, caused by the Mycobacterium tuberculosis bacteria. This disease is transmitted through the air, but is nearly impossible to catch with one social interaction with someone infected. If you are exposed constantly, though, you could catch this disease. 90% of the people who are infected with the disease will stay inactive, meaning they still have the bacteria in them, but they show no signs or symptoms and can't spread the disease. These people, however, can become active and become sick. This means that the remaining 10% have the active bacteria can result in serious sickness, even death.
Tuberculosis is an infection that spreads in your body through the lymph nodes and bloodstream. Although these bacteria can travel anywhere within the body, they are most likely to end up in the lungs. These bacteria kill the tissue in the organs they infect.
Symptoms of TB include: A bad cough that lasts 3 weeks or longer, weight loss, coughing up blood or mucus, weakness or fatigue, fever and chills and night sweats. Although TB can be fatal, there are ways to treat it. To treat TB, usually you take antibiotics ranging from six to nine month to destroy the disease, and the differences in antibiotics depend on your age, overall health, drug resistance, form of TB and the infected location in the body. People who have inactive TB can also take these antibiotics to prevent it from becoming active.
Mycobacterium tuberculosis: Mycobacteria are waxy celled, pleomorphic rods, which range from 2-4 micrometers in length, and .2-.5 um in width. These bacilli cells also have a high concentration of lipids in them, called mycolic acids. Because of this, they have a resistance to many antibiotics. Also, these lipids are hydrophobic and affect the permeability, allowing of liquids or gases to pass through, in the cell wall. These are found in habitats such as water or soil. This specific TB causing bacteria has been causing harm since before human times. Evidence shows that this transferred over to humans through cows in 8000-4000 B.C., through milk consumption. For more information on this bacteria, go to this website