Assessment: Infectious Diseases, Antibiotic resistance, Cataracts

Essay by bardouh2High School, 12th gradeA+, August 2008

download word file, 5 pages 0.0



Tuberculosis is an infectious disease caused by an infecting agent(pathogen). The pathogen that causes tuberculosis is in the form of rod-shaped bacteria and is known as Mycobacterium tuberculosis.


The tubercle bacillus affects the human host cell. The host-microbe intercation regarding tuberculosis is still unknown and is being researched at the moment.


The tuberculosis disease is transmitted via airborne processes. When a person has lung or throat cancer, sneezing or coughing causes the germ tubercle bacillus to become airborne. This germ is then inhaled from the air by another person and will become infected. In countries other than Australia, tuberculosis can be spread by drinking unpasteurised milk attained from infected feedstock.


COUGH: Constant coughing a common symptom of tuberculosis. This coughing is intense and contains thich cloudy mucus. This mucus is sometimes ejected with blood.

FATIGUE AND WEAKNESS: A tuberculosis patient never feels energetic.

There will be a constant feeling of sluggishness where the patient is unable to undertake and complete daily activities. A tuberculosis patient feels the need to sleep.


When the tubercle bacillus is inhaled, it may penetrate beyond the air ways into alveolar sacs in lungs. Then macrophages usually will engulf the bacillus and digest it via phagocytosis. The bacterium resist digestion and begin multiplying. Some macrohages carry these bacterium and travel through bloodstream. After weeks of exposure sweeling occurs in the alveolar sacs where bacterium containing macrophages clump together causing destruction of surrounding lung tissue. The tough tissue around the tubercle prevents bacilli from attaining oxygen and therefore prevents growth of bacilli. The bacilli remain alive but inactive. This is called Latent-TB infection.


The treatment of tuberculosis involves the consumption of 3-4 types of antibiotics for a prolonged period of 6-12 months, These antibiotica must be regularly and constantly taken without stopping for even a day. A strike in medicine consumption might lead to multi-grug resitant bacterium which is really dangerous for the patient. The 2 most common antibiotics used for TB are:

-- isoniazid

-- pyrazinamide

These antibiotics are most useful as they destroy the dormant bacteria which might become active in the future.

If in a patient antibiotic based treatment has no effect, then the only other alternative is surgical treatment. Surgical treatment involves the removal of the infected tissue from the patient's body. The surgical procedure is useful because the TB inected tissue causes the symptoms and pain. When the tissue is removed, the person feels better and becomes non-contagious.


The main form of prevention in kids is vaccination. Vaccination is used for kids while there are no vaccinations available for adults. The vaccine is called Bacillus Calmette-Guérin (BCG). BCG targets the prevention of spread of the disease.

Hospitals use different techniques to prevent spread of TB. Ultraviolet light can be used to sterilize the air and destroy the TB causing bacteria. Sterilization is also achieved with negative pressure rooms and special filters. Many hospitals also place TB patients in isolated rooms with controlled ventilation.


-- If a person is really sick and must be placed in a hospital, the patient is placed in a special room isolated from other patients and visitors

-- The patient's mouth must always be covered with a special mask

-- Contact with other people must be avoided

-- The patient's rooms must be aired out regularly since tuberculosis spreads in poorly ventilated and conjested areas


1. For a named antibiotic, describe how it affects bacteria at the cellular level.

PENICILLIN works by preventing a very inportant part of bacterial cell formation-the production of cell wall. The cell walls of bacteria are made of cross-linked polymers of peptidoglycan. The enzyme transpeptidase is vital for this reaction to occur. The beta-lactam structure of penicillin acts as a substrate and binds onto the active site of the enzyme and prevents the crosslinking of cell walls. As water moves in, the unprotected bacteria membrane will rupture and die.

2. Antibiotics do not cure all diseases. When are antibiotics used to treat diseases?

Antibiotics cannot cure or treat all diseases. Antibiotics work only in the case of bacterial, fungal and often parasitic infections. Antibiotics are useless against diseases caused by viruses.

3. What are the dangers of using antibiotics too often?

The truth about antibiotics is just becoming clear. Antibiotics do indeed cause the death of disease causing bacteria. As a human, in the intestines there is 3-4 pounds of beneficial bacteria and yeast. These compete for nutrients and beneficial bacteria come out on top due to higher numbers. Antibiotics destroy beneficial bacteria, and overtime the yeast will thrive. Yeast has ability of poking holes in intestinal wall lining, which causes leaky gut syndrome. These are dangers of continuous antibiotic consumption.

4. Why should a course of antibiotics be completed each time it is prescribed?

Each time a course of antibiotics is prescribed, it must be completed. If the course is not completed, the bacteria after not being exposed to the antibiotic for a while, will develop a strong irreversible resistance to that certain antibiotic, which means the

5. Bacteria develop resistance to particukar antibiotics. What are the implications of this in management of a disease?

Antibiotics are used to treat disease by killing bacteria. The incorrect use of antibiotis can lead to antibiotic-resistant bacteria. This is when bacteria are not affected by the antibiotic by changing its chemical composition and structure. These resistant bacteria are able to multiply in presence of antibiotic and can cause life threatening diseases. This is a serious health issue.

6. What alternatives are there to treating people with antibiotics?

Due to increasing numbers of antibiotic-resistant bacteria, alternatives are needed. In nature there are many herbs which inhabit many antibacterial(antibiotic) properties. Herbs such as garlic, ginger and goldenseal are known to be sued by herbalists around the world to treat bacterial diseases. These herbs are useful as they only kill bad bacteria, and not the beneficial ones.



Complicated cataract disease is cataract which develop as secondary effects in patients with glaucoma, detached retina, diabetes. Complicated cataracts can also result from exposure to ionizing radiation or infra-red rays.


BLURRED VISION: A person with cataract will find that vision is blurred, like looking through a cloudy glass. The gradual growth of cataracts causes worsening of vision with time. The cloudy part of lens might get larger making it difficult to see.

GLARE: Cataract patients experience glare. This means that car headlights, traffic lights and even sunlight seem too bright. This glare is accompanied by the appearance of a halo to cataract sufferers.

FADED COLOURS: For a cataract patient, colours will seem faded. There becomes a confusion between blues and purples. Also, in some cases colours are not visible at all, instead everything appears black.



Removes the cataract but leaves lens capsule. A 3 mm incision is made where cornea meets conjunctiva and small probe is inserted dividing cloudy lens into pieces by producing ultrasound waves. The cataract pieces are disposed of. An artificial lens is inserted into lens capsule


A larger incision of 10mm is made where cornea and sclera meet. Lens capsule nucleus is removed in one piece and lens cortex is vaccuumed out leaving capsule. An intraocular lens(IOL) is placed into empty lens capsule


This procedure removes the entire lens(including intact lens) using cyroextraction. This is when the lens sticks to an extremely cold metal probe for easy and safe removal


These new technologies are mainly advantageous for patients and society. Paitents who were catarct blind are able to see. Also, regaining sight often increases an individual's life span. Phacoemulsification is a really affordable process and is simple. These technologies eliminated need for anaesthetic and injections, and also made catarct removal quicker and much safer.