Bacteria are microscopic unicellular organisms that have no membrane bound nucleus. They play different roles in the ecosystem. Most of them are very helpful to the environment but some are disease-causing organisms. Pathogenic bacteria are very efficient in evading the immune system and one of the bacteria that have been able to manipulate our immune system to resist most immune defenses and survive is Mycobacterium Tuberculosis. This is a bacterium that causes tuberculosis, a debilitating disease that causes many deaths in poor and developing countries particularly HIV endemic areas. To further understand the potency and resistance of M. Tuberculosis and the efforts by leading scientists around the world in combating this bacterium, I will examine an article written by G. Maartens and R. J. Wilkinson called Tuberculosis.
The incidence of tuberculosis continues to increase worldwide. According to Maartens and Wilkinson, the annual incidence of tuberculosis among HIV infected individuals is more than 25% as compared to incidence of tuberculosis in the general population. This is devastating for infected people in sub-Saharan Africa because of the prevalence of HIV infection. The disease is transmitted when a healthy person breathe in air that contains droplets of an infected person. M. Tuberculosis hides and multiplies inside the cell and can shift, duplicate or delete genes to avoid immune response. These processes have enabled M. tuberculosis’ genomes to be considered as one of the most important bacteria. The bacterium presents different infective stages in different people. Some infected people will be asymptomatic with latent Tuberculosis infection or recover without signs of the disease and the bacteria will be dormant for years and reactivate when conditions are right particularly in the immunocompromised, elderly and children who have increased risk factors. When the bacteria are active in infected people, they will show symptoms ranging from coughing sometimes with blood, fever, fatigue to weight loss and chest pain.
Studies have revealed the different strains of M. Tuberculosis that exist in different parts of the world. This is true because the genes associated with infection in humans differ from population to population. Among the more than 800 strains studied, only six have adapted to specific population except for the east Asian strain which has high success rate of infecting people worldwide. Furthermore, studies have described the different strains of M. Tuberculosis as one of the reasons for resistance of the bacterium to treatment. This has created a tough job for scientists, researchers and health workers to come up with a viable treatment. Before going further with treatment, I will first discuss the studies on the diagnosis of tuberculosis. Many diagnostics tests are available and oldest of which is tuberculin skin test. Fluorescent microscopy is faster and more sensitive but it is unaffordable for many communities in poor and some developing countries. Since the disease is more prevalent in poor and developing countries, some studies have advocated in-house diagnosis test such as nucleic acid amplification test for tuberculosis. However, the test can sometimes present some inaccuracies and it is not financially sustainable for patients in these countries. There are some promising diagnostic tests that can detect active tuberculosis. For instance, Lalvani and colleagues determined that ELISpot analysis has a higher efficiency in detecting active tuberculosis even in HIV patients than TST which can give false positive tests because of the presence of different antigens. The downside of ELISpot analysis is it cannot differentiates between latent tuberculosis and active tuberculosis. For HIV patients, the most effective test is clinical based combined with radiology. There are other commercial tests available in the market such as QuantiFERRON TB Gold and T-SPOT.TB. Most of these diagnostic tests for tuberculosis usually take place in several days.
The treatment of tuberculosis occurs over a long period of time. The treatment varies depending on the infection, strains and resistance of the bacteria. The most common and effective medication for tuberculosis are isoniazid, rifampicin, pyrazinamide and ethambutol. The internationally recommended treatment is called directly observed treatment short course or DOTS. For complete and effective treatment of tuberculosis, patients must be supervised by clinics or their communities and must take all their medication over a certain period of time. For example, isoniazid, rifampicin, pyrazinamide, and ethambutol are taken for 2 months, followed by isoniazid and rifampicin for 4 months. Some of these drugs can have threatening side effects and any relapse during this treatment period can pose risk factors such drug resistance and infectious status. In addition, M. Tuberculosis particularly in HIV patients has developed some resistance to some of these drugs. Other promising sign in the fight against tuberculosis is vaccination. In some studies, administration of dead M. Veccae or BCG vaccination showed some increased immune defense against M. Tuberculosis. Nevertheless, a person vaccinated with M. Veccae or BCG can test positive for tuberculosis antibodies even he does not have an active tuberculosis. Some clinical data have also shown the result of these vaccines as inconclusive.
In summary, M. Tuberculosis is one of the most devastating and elusive bacteria in the world. It has caused tremendous suffering to humankind. As intracellular bacteria, their ability to mutate their genome and use the cell mechanism to evade the immune defenses has created an enormous task for researchers and scientists to come up with viable method to treat tuberculosis. There are greater risk factors when the disease is present in an HIV infected patient because of the weakened immunity. The article describes various studies and researches to combat tuberculosis. In my opinion, there is not enough work by leading drug makers to combat the diseases. Since the disease is most prevalent in poor and developing countries, the incentive for drug makers to spend large sum of money to come up with a vaccine or treatment is very low. Drug makers are beholden to their shareholders to show profits and most of the people in countries where tuberculosis is endemic such as Vietnam and South Africa cannot afford these drugs. However, there is some hope because of nonprofit organization such as the Bill and Melinda Gate foundation donation of millions of U.S dollar to scientists and researchers to combat tuberculosis. The eradication of tuberculosis will require a concerted effort by everyone particularly the TB patients as well as the governments. TB patients must strictly follow their treatment to prevent the spread of the disease and governments must fund researches about TB and implement policies to protect healthy citizens.
