Hubs1401 Human Bioscience- Clostridium Tetani Assessment Answers

a. For each of the three wound observations indicate, and provide a rationale, as to whether it is a sign or a symptom.

b. Discuss the physiological basis of the first observation.

c. Discuss the physiological basis of the second observation.

d. Discuss the physiological basis of the third observation.

3. Development and benefits of fever.

a. How did Mary fever develop?

b. Discuss two ways in which fever is beneficial.

4. Possible sources of contamination and modes of transmission

a. Name one endogenous source of contamination and discuss the mode of transmission from the source to the new host.

b. Name one exogenous source of contamination and discuss the mode of transmission from the source to the new host.

5a. Given the colonizing organism was Staphylococcus aureus, discuss why Augmentin is an appropriate prescription? 
b. Describe the added benefits that Augmentin provides, with reference to the role of the major ingredients in Augmentin.

Answers

1a. Clostridium tetani, a bacterium that can infect wounds exposed to soil or dirt is an endospore-forming, rod shaped bacterium that can cause tetanus. In Mary's case she had got an open wound when working in her garden and this could have exposed her wound to the soil and also to the bacterium C. tetani. Tetanus is caused due to two toxins released by the bacterium, tetanospasmin and tetanolysin, both of which are neurotoxins. There is however the tetanus booster vaccine which can be given to Mary so that she gets adequate protection (Immunise.health.gov.au, 2017).

b. Since Mary is 50 years of age, she should receive the tetanus booster vaccine, particularly if she has not received a vaccine in the past 10 years. There have been cases where even a booster prior to the injury has not been able to prevent tetanus. So, it is best that soon after an exposed wound is treated, it should be followed by a tetanus toxoid booster (Immunise.health.gov.au, 2017). A tetanus booster soon after the injury can increase the concentration of circulating antibodies against tetanus toxins in Mary's blood making her immune system capable of fighting a Clostridium tetani infection if the need arises.

2 a. The moment an injury occurs, the acute inflammatory response swings into action. The release of several biochemicals at the wound site try to bring about homeostasis and control the entry of pathogens that could cause an infection.

b. The edges of the wound are hot to touch and red due to a sequence of acute inflammatory response that is triggered in the event of an injury. The chemicals that cause inflammation and are released at the injury site are the complement system components, histamines, prostaglandins and some kinins. The combined effect of these compounds and some cytokinins increases the blood flow to the site so the edges appear to be red in color. Nitric oxide plays a role in vasodilation, so the capillaries near the cut are dilated for increased blood flow. The prostaglandins, E1 amd E2 increase the vascular permeablity so that neutrophils can extravasate from the capillaries into the surrounding tissue and they also relax the smooth muscles ofthe blood vessels. An increase in the temperature at the injury site causes the cells to metbolize at a faster rate, so the edges appear to be hot (Craft, 2015).

c. There is evidence of swelling in the area around the injury. It is also known as edema and occurs due to the oozing out of a fluids from the blood vessels. This fluid occupies the spaces between the tissues and this symptom is also accompanied by pain. The pain reduces movement and due to lack of movement of the affected area patient can recover from the injury faster (Marieb Hoehn, 2014).

d. A purulent and odorous discharge is noticed from the wound and by then Mary is also febrile. A discharge of this nature is a clear indication of an infection and that is why the healthcare staff sent a wound swab for culture testing and identification of the pathogen and its antibiotic sensitivity (Bowler, Duerden, Armstrong, 2001). Following an infection, the immune system responds by increasing the volume of exudate and there is an increase in the swelling and pain. An oral antibiotic can be given to the patient in order to treat infection by a pathogen (Craft, 2015).

3a. Fever is also an important part of the immune response. Fever is defined as a core temperature that is measured rectally and is equal to or more than 38⁰C. Since Mary suffered from an infection endotoxins released from the infectious bacteria triggered the release of cytokines interleukin-1, interleukin-6 and tumor necrosis factor- (TNF ), the three pyrogenic cytokines. These in turn cause the release of endothelin I, cortocotrophin releasing factor and prostaglandin E2. The pre-optic area of the anterior hypothalamus is acted upon by the pyrogens so as to trigger a fever. The temperature of the body begins to rise as the body begins to produce and conserve heat (Craft, 2015).

b. Fever is beneficial because it can stop the multiplication of the pathogenic bacteria. Fever depletes three minerals, copper, iron and zinc that are vital for bacterial replication and reduces the rate at which bacterial pathogens multiply. Phagocytosis also occurs at a faster rate and the elimination of pathogens occurs much faster (Marieb Hoehn, 2014).

4a. Staphylococcus aureus is a natural inhabitant of the human skin and also a harmless commensal that remains associated with the mucosa of the nasal cavity, the vagina and the oro-pharyngeal cavity. Transmission by contaminated hands is possible and the source for most endogenously transmitted infections. Once the bacterium is transferred to an injured site, such as a cut, it finds more nutrition, in the moist subcutaneous environment and quickly turns into a pathogen, that delays healing. Antibiotics may then have to be administered to treat the infected wound (Demidova-Rice, Hamblin, Herman, 2012).

b. An exogenous source of contamination could be hands of healthcare personnel or surfaces, such as door handles or showers contaminated with Staphylococcus aureus. Although in Mary's case her wound was contaminated with soil, soil bacteria are not known to cause wound infections. S. aureus infections are usually known to be endogenous in origin, when exogenous, the contamination usually occurs due to lack of hand washing by healthcare staff dressing the wound (Lee, 2016).

5a. Mary's wound swab report confirmed that she suffered from an S. aureus infection on the wound. The report also stated that the culture was sensitive to Amoxycillin. But several strains of Staphylococcus are known to be resistant to beta lactam antibiotics and Augmentin is an antibiotic that is effective against antibiotic resistant S Aureus.So it is an appropriate choice of an antibiotic to treat her condition (Bullock Manias, 2017).

b. Augmentin is a combination of Amoxycillin and Clavulenic acid. The mode of action of Amoxycillin is that it blocks the formation of the peptidoglycan cell wall in bacteria. But due to the development of antibiotic resistance, the beta lactam antibiotics were rendered ineffective against bacteria. Bacteria developed the ability to synthesize the beta lactamase enzyme which causes breakdown of the beta lactam ring, so even in the presence of the antibiotic the bacterial cell wall could be synthesized and multiplication could continue unabated. The addition of clavulenic acid to amoxycillin made the antibiotic effective again because clavulenic acid could block the activity of beta lactamase enzyme and the beta lactam could once again interrupt peptidoglycan cell wall formation. Thus Augmentin can be used as an effective therapy against S. aureus infection (Bullock Manias, 2017)

References

Bowler, P. G., Duerden, B. I., Armstrong, D. G. (2001). Wound Microbiology and Associated Approaches to Wound Management . Clinical Microbiology Reviews, 14(2), 244 269. https://doi.org/10.1128/CMR.14.2.244-269.2001.

Bullock, S., Manias, E. (2017). Fundamentals of pharmacology (8th ed.). Frenchs Forest, Australia: Pearson Australia.

Craft, J. . (2015). Understanding pathophysiology (2nd Australian and New Zealand ed.). . Chatswood, Australia: Elsevier.

Demidova-Rice, T. N., Hamblin, M. R., Herman, I. M. (2012). Acute and Impaired Wound Healing: Pathophysiology and Current Methods for Drug Delivery, Part 1: Normal and Chronic Wounds: Biology, Causes, and Approaches to Care. Advances in Skin Wound Car.

Immunise.health.gov.au. (2017, August 1). /Aus-Imm-Handbook.pdf. Retrieved from https://immunise.health.gov.au: https://immunise.health.gov.au/internet/immunise/publishing.nsf/Content/7B28E87511E08905CA257D4D001DB1F8/$File/Aus-Imm-Handbook.pdf

Lee, G. . (2016). Microbiology and infection control for health professionals (6th ed.). . Melbourne, Victoria : Pearson Australia.

Marieb, E., Hoehn, K. (2014). Human Anatomy Physiology, Global Edition. Pearson Education Limited.