Question

8. Tuberculosis

The genus mycobacterium contains over 50 species with several human pathogens of concern.

Mycobacteria are distinguishable from other types of bacteria by the presence of wax layers and

high molecular weight fatty acids (mycolic acids). This complex, external structure offers

protection from acids, drying and some germicides. In fact, mycobacteria are also referred to as

acid-fast bacilli because acid treatments will not result in decolorization during staining.

One of the mycobacteria species of medical interest is Mycobacterium tuberculosis, the

causative agent of tuberculosis (TB). TB is a disease that affects millions of people worldwide.

In fact, the Center for Disease Control (CDC) estimates that one third of the total world

population is infected with TB.

M. tuberculosis normally attacks the lungs, but can infrequently infect other areas of the body.

An infection with M. tuberculosis can result in latent TB infection or TB disease. Latent TB

infections occur when M. tuberculosis is present but not active. People with latent TB infections

do not exhibit any symptoms, do not feel sick, and are not infectious. If the M. tuberculosis

becomes active and multiplies, the person will develop TB disease.

People with TB disease are infectious. TB is spread primarily by M. tuberculosis becoming

airborne in droplets of respiratory mucus when a person with TB disease coughs, sneezes,

sings or speaks. By breathing in the airborne bacteria, the new person is inoculated. Symptoms

of TB disease include pain in the chest, coughing up blood or sputum, or a bad cough that lasts

three weeks or longer. TB is tested for by either a TB skin test (TST) or by a TB blood test.

Direct identification of acid-fast bacilli in sputum is also used to detect M. tuberculosis. Current

treatments for TB include long term use (6 to 24 months) of a combination of medications.

Questions:

1. What are some of the other symptoms of TB disease not mentioned above?

2. In the U.S., Certain populations have a disproportionate rate of TB. Which populations

are these?

3. How have antibiotic resistant strains of M. tuberculosis hindered treatment?

4. Why are many health care workers required to get tested for TB?

5. A chest x-ray is used occasionally to detect lung damage in TB patients. What is the

radiologist looking for in the x-ray?

6. How are giant African rats being used to detect TB?

7. What other sites in the body can be infected by M. tuberculosis?

8. What is the primary habitat for M. tuberculosis?

Answer 1

1 a bad cough lasts 3 weeeks ,pain in chest ,coughing up blood or mucous other symptoms include fever ,weightloss ,weakness ,chills ,sweating at night

2 hispanics /latinos impacted by tb for a great extent

3it is very important that people who have taken tratment should finish medicine if they stop taking drug too soon they can become sick again tb bacteria that are still alive become resistant to those drugs and it becomes more harder and expensive to treat certain drugs require activation of redox enzyme in micobacterial cytoplasm to become cytotoxic the prodrug activation process produces reactive o2 and free radicals that exert micobactericidal activity .if the reactive o2 fail to kill the bacterial cell they wil turn bad by promoting cellular mutagenesis and the emergence of drug resistant mutation

4 tb is commmunicable by inhalation of airborne particles when patients with tb visit healrth care workers they transmit the disease

5 a pa chest x ray shows signs of infiltrates or consolidation and cavities in upper lungs with or without mediastinal or hilar lymphadenopathy

6 they have an excellent sense of smell and are trained to respond consistently in one way if the sample contains tb bacillus and to respond in another way if it do not contain bacilli

7 tb can infect any place in body like inner organs like bone ,brain ,spine ,kidney

8 macrophages are the primary habitat of m.tuberculosis humans are the reservoirs when it is phagocytosed by macrophages they are unable to kill the bacterium