HBM2105 Medical Microbiology And Immunity


You will write a creative essay as follows:

* Each student will complete this assignment independently. Students will be asked to create a non-technical story from the perspective of a microbe you choose (i.e.

The microbe will take the role of the writer and tell their story. This is a straightforward yet factual task that any 1st-year university student would understand.

* Students must choose a microbe, such as a bacteria, virus, or parasite, and identify the key ideas. These will be the foundation of their essay, which will describe the pathogenesis and infection of their microbe.



I am a bug. I am proud to be a bacterium.

This means that I belong the genus Salmonella. A beautiful name we did not inherit from our fathers, but were given it by Dr Daniel Salmon who first learned much about us (Chugh, et al. 2008).

Like the other S. enterica serovars Salmonella Typhimurium, and S. Enteriditis I cause severe diseases in the human intestinal tract.

Despite sharing many of the same features, we are very different (Younus (2014)).

My personal passion is to spread typhoid fever to humans. It’s so much fun!

As I mentioned, my specialisation is in Typhoid Fever, which kills approximately 17million people annually.

Due to their rapid growth, 600,000 people are my human hosts who succumb to the disease (Younus (2014)).

I am an obligate parasite and have no other reservoir than humans.

Humans don’t know anything about the origin of my infections. However, they believe that I caused the deaths famous humans like Rudyard Kipling the British poet and Wilbur Wright the inventor of the aeroplane.

Humans know of the 17th century outbreak I started in Jamestown in Virginia. It was a typhoid epidemic that killed approximately 6,000 people.

Although it is not common in the USA, the possibility of recurrence is real.


Karl J. Erberth was the first scientist to isolate me in 1880.

I’m a multi-organ pathogen. My home can be found in lymphatic tissues, particularly in small intestines.

I’m not known to reside in animals. However, I enjoy living in poor countries that have poor sanitary systems. It is a safe environment for me to operate in and for my family. (Younus (2014).

There are not enough antibiotics available to me in these countries so people who travel to Asia and Africa or Latin America will be at a greater “risk” of experiencing my effects.

A microbiological perspective of who I am

While I admit that I am far too tiny to be seen by the naked eye, it is something I love about helping others down by spreading their disease and organs.

I am an enteric bacillus and gram-negative bacterium of the Enterobacteriaceae Family.

I am very mobile but mostly a facultative, anaerobic bacterium. However, I can take several antibiotics.

In the laboratory, there are more than 107 strains (Garrett 2016).

Many of the strains I have already isolated possess metabolic characteristics that differ from those found in nature.

They also have different levels of virulence. I also have varying multidrug resistance genes that allow me to complicate the treatment for typhoid in humans in those regions where resistance has been made more common (Younus, 2014.

Humans can always identify us by diagnostic identification. Therefore, they feed us MacConkey and EMB.

Because they know that me, including my strains, remain a strictly non-lactose fermenting bacterium in nature.

Because I do not produce gas, especially when I’m cultured in TSI media, I can be distinguished from other Enterobacteriaceae (Garrett (2016)).

It seems you don’t enjoy producing gas either!

Typhoid/ Enteric Fever

Infecting someone with typhoid virus can cause them to develop enteric fever.

Typhoid fever can cause a sudden onset and/or persistent fever. It can also lead to severe headaches, nausea, loss of appetite, severe constipation and diarrhoea.

Additionally, I may cause meningitis in some people (Chugh and colleagues, 2008).

If we are not treated with antibiotics effectively, or if we suffer from typhoid-related complications, there is a chance of a 12- to 30% mortality rate.

These individuals are saved by typhoid-related treatment, which has a 99 percent survival rate (Younus (2014)).

This means that antibiotics have destroyed our bodies.

Virulence Factors

There are a few things that make me either a true bug or a highly effective pathogen.

I first got an endotoxin, which is very common in any gram-negative micro-organism.

My Vi antigen, which is a well-known gene that increases my virulence within human organs, also helps me.

I also produce and excrete invasion proteins that allow cells that are not phagocytic to lift me up like a baby so I can live in them (Mweu English, 2008).

It’s so much fun, you probably know.

Furthermore, I have the ability to inhibit the oxidative burst from human leukocytes. This renders their innate immune response extremely ineffective.

With these attributes, I can float like an insect and sting like one.

My colon is more common in healthy people than those with my colonies.

Patients with poor hygiene are more likely to contract secondary infections.

People who eat shellfish in water bodies that contain our colonies are more likely to contract typhoid disease.

Even so, we all know that the greatest source of infection is water that has been contaminated by the urine and/or excrement of infected people.

Our colonies have an inoculum that is large enough to trigger typhoid fever.

Humans report that this condition (typhoid/enteric flu) is the most commonly reported infective.

Our triumphant entry into the bodies and minds of people occurs most often through their ingestion.

We cannot, however, be transmitted to healthy individuals by aerosol means.

Guha (2016). Once we have been ingested, our small intestines begin to multiply within one to three weeks.

In order to spread to many other organs or tissues, we then wreak havoc on the intestinal wall.

Our destructive abilities are now very evident and the host’s natural defense system can do little to stop them.

We are able to inhibit oxidative depletion while simultaneously being taken up and absorbed by cells. Once taken up, our bodies can also grow. (Mweu & Engleh, 2008).

It has been proven that I can be transmitted via the faecal/oral route from asymptomatic people.

Garrett (2016) has also shown that 2-5 percent of people who were infected previously by my colonies remain chronic carriers and show no symptoms.

They do however shed us in stronger form so we can infect others.

Mary Mallon, a food handler, who infected 78 people and caused the deaths of 5, was a carrier. (Toichuev (2011)

According to human reports, such carriers can be very dangerous for the public health sector as they do not show any symptoms and yet pass on our colonies to others.

Although the destruction I do to the human organs can be reversed, it is even less if my colonies are not multiplying before they get too much attention (Wang et. al. 2014).

My feasting behavior can be avoided by humans by preventing faecal contamination of their drinking waters and food supplies. (Wang et. al., 2014).

Humans must control my transmission by ensuring hygiene, proper waste management, effective treatment of the sick, and proper hygiene practices. They also need to be aware that I am primarily transmitted from infected individuals.

My recommendations to reduce my population have been mainly implemented in advanced societies, which has a low incidence rate of typhoid.

In the US, for example, there are approximately 400 cases per year. However, this occurs almost exclusively in those who have traveled recently to developed nations (Garrett 2016).

The effectiveness of a vaccine, however, is questionable. I have broken its efficacy many times.

Also, when humans use large amounts of inoculum, we overpower our body immunity and cause disease.

Therefore, I believe the significance of the disease which I have caused has been significant in history.

While I am able to thrive in developing nations, an area that is plagued by disasters and poor sanitation is where I prefer to live (Toichuev 2011, 2011).

Today, people are concerned about my epidemics and/or outbreaks. They also fear that my diseases could spread to large numbers. Guha (2016) says that this is because I’m not easy to identify and travel makes me a threat worldwide.

I find it very concerning that antibiotics, including vaccines, could be developed more rapidly to destroy many of our colonies and a significant portion of our worldwide population.

But I’m still considered a gallant buggy in human history.

My name is always mentioned in their history.

Refer to

Chugh T., Kothari A., and Pruthi A.

The Burden Of Enteric Fever.

The Journal of Infection in Developing Nations, 2 (04).

The surveillance of enteric fever in Asia: Estimating community burden.

International Journal of Infectious Diseases. 45. p. 64.

Journal of Medical Science And Clinical Research, 04(12), pages 14855-14856.

Mweu E., and English M. (2008).

Typhoid fever in Africa children.

Tropical Medicine & International Health 13, pp.532-540.

Journal of Clinical and Diagnostic Research.

The Impact of Climate Changes and Environmental Pollution on Typhoid Fever Seasonal Fluctuations.

Why have a special issue in JIDC about enteric fever.

The Journal of Infection in the Developing Countries, 2 (04).

Wang, Y. Huang K. and Huo Y.

Comparison of the proteomic profiles of Salmonella Typhimurium versus Salmonella Typhi.

Journal of Microbiology, 52(1) pp.71-76.

Consuming eggs and meat from carriers birds can cause Typhoid Fever (salmonellosis), which is a public-health problem.