Treatment/ Prevention

 Due to the nature of the disease, the treatment programme must be endured for at least six months; sometimes even up to a year. the patient is usually prescribed a daily dose of a combination of drugs, including; isoniazid, rifampicin, pyrazinamide and ethambutol for the first two months and then prescription of the latter two are stopped. The most commonly used drugs are a combination of bacteriostatic and bacteriocidal with differing mechanisms of action, such as; inhibition of protein transcription and translation, intervention with fatty acid production and removal of the protective cell wall barrier. A patient undergoes sputum examinations following two and four months of treatment and are considered cured when if the results for the smears are negative. In addition, further follow up checks are included to prevent a patient from entering re-lapse.

The persisting issue that prevents a much larger scale of control for TB is the fact that the bacteria can very quickly develop resistance to a particular drug; or even a combination of many. It is therefore crucial to initially utilise early diagnosis and tracking of patients with multi drug resistant (MDR) strains of the bacteria and then use variations of different drugs with different pharmokinetics for a period of up to one year. Furthermore, failure of treatment in chronic MDR-TB may require the use of reserve drugs that are kept as the last resort to prevent the bacteria developing resistance to them, such as, amikacin which binds to the 30S ribosomal subunit and therefore prevents protein synthesis. 

Side-effects

There are a range of side effects that can occur from the range of drugs in the programme. These include:

• Skin rashes 
• Deafness
• Vertigo
• Jaundice and hepatitis
• Visual impairment
• Decreased urine output

Directly Observed Therapy - Short Course (DOTS)

The World Health Organization (WHO) launched a new programme in 1994 to try and control the rising worldwide TB epidemic; it was called directly observed treatment, short course. The scheme involves a health worker being present when the patient is administering the anti-tuberculosis drugs so that it is made sure they follow the strict treatment programme. It is very important that the patient does not miss a drug dose as this gives the bacteria the opportunity to grow and spread, as well as developing into drug-resistant strains. Many people have trouble remembering to take their medicines for the duration of six months and some even stop taking the drugs when they start to feel better; however, it is important that this is prevented. The strategy has had a good level of success during the time it has been implemented with a global treatment rate of 84% and is now included in 184 countries. Further use of the strategy to try and eliminate TB as a worldwide epidemic continues with guidelines set out based on five key components of DOTS:

• Political commitment with increased and sustained financing
• Case detection through quality-assured bacteriology
• standardized treatment with supervision and patient support
• An effective drug supply and management system
• Monitoring and evaluation system 

Bacillus Calmette-Guerin (BCG) vaccination

Since 1953 there has been a vaccination program set in place to combat TB. The BCG vaccination involves using a live cultured strain of Mycobacterium bovis which has lost its virulence in humans but is still strong enough to induce an immune response. Prior to administering the vaccine, patients should participate in a tuberculin test to detect whether they have already been exposed to the bacteria or present active TB.  Furthermore, it is important that patients fulfil certain criteria before they can be administered the vaccine, such as:

• They must not have a past history of TB or have a positive skin test
•  It cannot be given to patients with a compromised immunity due to other treatments or diseases; this    specifically includes HIV- positive patients 
• They have had another vaccine less than 3 weeks before

The success of the vaccine has been the subject of much recent debate whereby it is reported the protective effect is between 60-80% and lasts for around 15 years. In 2005, the vaccination program to immunize school children was stopped to due falling cost-effectiveness and low incidence rates. It is now generally considered only important to vaccinate infants (under 12 months) or people living in high risk area. 

 "BCG Apparatus" image used courtesy of Wikimedia Commons under Creative Commons License: Original image

Current drug development

Continuation of research is crucial to counter the rising problem of MDR-TB. One organization in particular, TB Alliance, is overseeing the clinical trials of a number of new potential medicines. A drug pre-existing drug, Moxifloxacin, is currently the best contender for a new treatment against TB; progress through to phase 3 trials has indicated that it could decrease the treatment region by 2 months. Moxifloxacin also offers an advantage by not interfering with anti-viral drugs used at the same time for patient suffering with HIV-TB.