Medical Microbiology Report: Tuberculosis Case Study

This medical microbiology report focuses on tuberculosis, a contagious disease caused by Mycobacterium tuberculosis. The report details the pathogen's characteristics, transmission via airborne particles, and the body's immune defenses, including macrophages and interleukins. It outlines symptoms like coughing, chest pain, and weight loss, along with diagnostic methods such as chest X-rays, sputum tests, and the Mantoux test. The report covers treatment using drugs like isoniazid and rifampicin, and preventive measures such as ventilation and hygiene. A case study of a pregnant woman with tuberculosis is included, highlighting the disease's impact and treatment considerations. The report references several sources to support the information presented.

Running Head: MEDICAL MICROBIOLOGY
Medical Microbiology
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Part 1: Causal Organism of Tuberculosis
Tuberculosis is a contagious disease that is transmitted by the causal organism
Mycobacterium tuberculosis bacteria. It infects the lungs mainly but can affect the other parts
of the body as well. Mycobacterium tuberculosis belongs to the Mycobacteriaceae family.
These pathogenic bacteria are characterised by an abnormal waxy coating on its cell surface
due to the presence of an acid known as mycolic acid. It was first discovered by Robert Koch
in the year 1882 (World Health Organization, 2013).
Part 2: Entry and transmission of pathogen
Mycobacterium tuberculosis is a pathogen that is transmitted through air borne particles is
known as droplet nuclei. These infectious droplet nuclei are released from an infected person
through coughing, sneezing, shouting or singing. These airborne droplet nuclei can remain
suspended for several hours in the environment. This pathogen is transmitted through air and
not by surface contact. Transmission occurs when a person inhales the infectious droplet
nuclei. This droplet nuclei containing the pathogen traverse the mouth or the nasal passage
followed by the upper respiratory tract, bronchi and finally reaches the alveoli of the lungs
(Getahun et al., 2015).
Part 3: Immune defences against the pathogen
When the pathogen Mycobacterium tuberculosis, infects an individual it attacks the lungs
primarily. The first line of defence is initiated by macrophages. Interleukins are certain
immunity proteins that are activated in the macrophages in response to the pathogenic attack.
But interferon also aids in exacerbating the tuberculosis. Two types of interleukins are
involved in the process. The interleukin 1 fights the bacteria and interleukin 2 aids in invasion
of the disease. This weakens the immune response (O'Garra et al., 2013).

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Part 4: Symptoms of the tuberculosis
The symptoms of tuberculosis involve coughing that is mild to severe lasting for more than
three weeks, sometimes coughing up blood is also encountered. Observable chest pain with
breathing or coughing. It accompanied by unintentional weight loss, fatigue, fever, night
sweats and chills. Loss of appetite is also observed.
Part 5: Diagnosis, treatment and control
The diagnosis of tuberculosis involves the initial test of chest X-ray to check for the presence
of cavitation due to the presence of the bacterium in the lungs. This is not a confirmatory test
and it is often followed by the sputum test. The sputum is subjected to acid fast staining
which is an ancient microscopic technique to detect the presence of the pathogen. The most
common test for tuberculosis exploited is Mantoux test. This test exploits injection of
tuberculin protein intradermally and observing the skin test after 48-72 hours of injection.
The localized swelling is the basis of detection for this test. Another blood test exploited for
diagnosis of tuberculosis includes Interferon Gamma release assay. This blood test can be
exploited in place of the Mantoux test (Dye et al., 2013).
The precautionary measures that should be followed to control and prevent tuberculosis
involves-
 The pathogen remains suspended in the air for several hours hence effective
ventilation would reduce the chances of acquiring tuberculosis.
 There should be allowance of natural light in the rooms this is because Ultra violet
light from the sun kills the tuberculosis bacterium.
 The most important of all includes maintenance of good hygiene that is covering the
mouth while coughing or sneezing. This effectively reduces the spread of the bacteria
(Ryu, 2015).

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The treatment of tuberculosis exploits the use of isoniazid, rifampicin, pyrazinamide and
ethambutol or streptomycin. This is carried on in the initiation phase and once the
tuberculosis isolate is effectively susceptible, the fourth drug either streptomycin or
ethambutol whichever is administered to the patient can be discontinued in the continuation
phase (Zumla, Nahid and Cole, 2013).
Part 6: Case study
A 20-year old women in her first trimester went for her routine check-up. She complained
that she had persistent cough for quite a long time and in the past to months she observed an
unintentional weight loss of 4kgs.
On examining no significant findings was observed not even lymphadenopathy but
crackles were observed in the upper lobe of the left lung. The blood test revealed that the
CD4 count of her blood was low as 320cells/mm3. The sputum sample was taken and send for
acid fast staining and the test result was positive.
Untreated tuberculosis poses a big threat to the mother as well as the foetus. The
tuberculosis drugs do not negatively impact the outcome of pregnancy. The drugs cross the
placental membrane but poses no harm to the foetus. Untreated tuberculosis of the pregnant
women may cause low weight of the babies and they also might be infected with the
pathogen.
The first line drugs for treatment of tuberculosis were isoniazid, rifampicin, pyrazinamide
and ethambutol for the initial two months and then in the continuation phase isoniazid and
rifampicin alone are administered.

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References
Dye, C., Glaziou, P., Floyd, K. and Raviglione, M., 2013. Prospects for tuberculosis
elimination. Annual review of public health, 34, pp.271-286.
Getahun, H., Matteelli, A., Chaisson, R.E. and Raviglione, M., 2015. Latent Mycobacterium
tuberculosis infection. New England Journal of Medicine, 372(22), pp.2127-2135.
O'Garra, A., Redford, P.S., McNab, F.W., Bloom, C.I., Wilkinson, R.J. and Berry, M.P.,
2013. The immune response in tuberculosis. Annual review of immunology, 31, pp.475-527.
Ryu, Y.J., 2015. Diagnosis of pulmonary tuberculosis: recent advances and diagnostic
algorithms. Tuberculosis and respiratory diseases, 78(2), pp.64-71.
World Health Organization, 2013. Global tuberculosis report 2013. World Health
Organization.
Zumla, A., Nahid, P. and Cole, S.T., 2013. Advances in the development of new tuberculosis
drugs and treatment regimens. Nature reviews Drug discovery, 12(5), p.388.