Causal Organism of Tuberculosis

Running Head: MEDICAL MICROBIOLOGY
Medical Microbiology
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Medical Microbiology1
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).