Mycobacterium Leprae and Mycobacterium Tuberculosis - Essay Example

An estimate of 1.7 million deaths were reported by WHO caused by tuberculosis (TB) in the year 2004 (St Georgiev, 2009, p. 103). This highlights the destructive and intensely pathogenic nature of M. tuberculosis and the need to study it thoroughly. M. leprae, discovered in 1874, causes a chronic infectious disease leprosy which is found throughout the world. However, the highest prevalence rates are found in India, China and Africa. In India 3.2 million people are suffering from leprosy (Sehgal, 2004, p.5). The considerably higher estimates in the above mentioned states makes this pathogen quite intriguing and worth research.

The devastating nature of the M. tuberculosis and M. leprae and the increasing frequency of the infectious diseases caused by them, necessitates further study and awareness about these pathogens. The paper will discuss general characteristics of mycobacterium and the following features of the specific pathogens in the given sequence- nutritional requirements, growth rate, general features of pathogen, transmission of disease, disease progression, skin testing, treatment and immunization. The general characteristics of Mycobacterium are applicable to all the members included in this genus.

Mycobacteria are strictly aerobic acid-fast bacilli and are neither gram-negative nor gram positive. The reason for this property is the high lipid content in their cell walls. This unusual characteristic of their cell walls make them resistant to many disinfectants, drying and corrosive chemicals. However, they are not resistant to heat or ultraviolent radiation. They mostly cause diseases that lead to the formation of slowly progressing granulomatous lesions (Harvey et al 2007, p. 185; Levinson 2008, p. 161). The highly resistant nature of mycobacterium explains the easy transmission and difficult prevention of the infectious diseases.

Mycobacterium tuberculosis The general features about the M. tuberculosis highlight the growth rate of the pathogen, nutritional requirements, strains of the bacterium which are helpful in assessing the treatment plans and diagnostic therapies. M. tuberculosis grows at a very slow pace and it takes 18 hours to get doubled. Thus, in comparison to other bacteria it has a slower growth rate. As mentioned earlier, M. tuberculosis is an obligate aerobic, hence it requires oxygen majorly for its growth.

The media used for its growth is Lowenstein-Jensen medium that uses complex nutrients to support its growth. These include egg yolk and some dyes like malachite green. The dyes are used to inhibit the growth of other bacteria present in the sputum samples (Levinson 2008, p. 161). Although the M. tuberculosis has a very slow doubling rate, it can be grown quite favorably in the laboratory environment by providing supporting nutrients. The important properties of M. tuberculosis include the appearance and dimensions, the virulent strains and the chemical compositions. M. tuberculosis appears as curved slender rods that are 2 to 4 um long and 0.2to 0.5 um wide.

The bacterium possesses a particular “cord factor” that causes its virulence. The virulent strains grow in a serpentine fashion while the avirulent strains lack this property. The high lipid content in cell wall constituting of mycolic acids and phosphatides are the factors for causing acid-fact property and caseation necrosis, respectively (Levinson 2008, p. 161; St Georgiev 2009, p.106). M. tuberculosis is