Physiological Basis of Wound Healing, Sources of Contamination and Antibiotic Rationale

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1. Physiological basis of the wound observations (Total: 10 marks)
Research shows that there are four stages of wound healing: Hemostasis, Inflammation,
Proliferation and Remodelling. (Orsted et al, 2018). Immediately Mary’s injury occurred, the
body reacted and the healing process began. Hemostasis is the immediate phase and occurs
within minutes of the injury. The platelets are the cells involved, their job being sealing off
the damaged blood vessels, which constrict in response to injury by forming a stable clot.
Adenosine Diphosphate (ADP) influences the working of platelets by leaking from injured
cells and they stick to the uncovered type 1 Collagen. They then secrete sticky glycoprotein
which causes more platelet aggregation. Thrombin is released which initiates the conversion
of fibrinogen to fibrin. Fibrin forms a mesh which strengthens the aggregate, forming a clot.
Platelets also secrete growth factors which recruit cells like neutrophilis and monocytes and
initiate the recruiting of fibroblasts by the epithelial cells bring about the the next stage,
inflammation (Altmeyer, Hoffmann, Gammal, & Hutchinson, 2012).
Inflammation is the second phase. (Orsted et al, 2018). It is characterized by erythema
(redness of the skin), warmth and swelling, often linked to pain This is the stage Mary’s
wound currently is and lasts upto four days after injury. The constriction of vessels in the
hemostasis stage is follwed by dilation in the inflammation phase. Here, cleaning of the
debris occurs done by neurophilis cells or polymorphonuclear neutrophilic leukocytes
(PMNs).The blood vessels in response release plasma and PMN’s. So as to provide defence
against infection, the neutrophilis phagotize debris. They also take part in oxidative bacteria

killing, increasing the effectiveness of antibiotics, but as they digest bacteria and debris, they
die. Monocytes then come in and digest the tissue further. Cytokines and growth factors help
cells communicate. They bind to receptors on target cells and stimulate them to move and
they synthesize releasing substances needed to form the extracellular matrix which plays a
role in healing. Macrophages and extracellular matrix come into contact and are able to
phagotize bacteria providing a second streak of defence. They help in resolving inflammation
by degrading enzymes from the matrix metalloproteinasis (MMPs). Uncontrolled activities in
MMPs may cause degradation in the new formed tissue thus a delay in would healing
(Altmeyer et al., 2012).
2. Possible sources of contamination and modes of transmission (Total: 10 marks)
2.1 Name one endogenous source of contamination and discuss the mode of transmission from
the source to the new host. (5 marks)
One example is Enterobactericeae (Samuelsson, 2013). Enterobacteria pathogens cause
urinary tract contagions and septicaemia cases. The most common mode of bacterial
transmission is contact transmission and it is divided into two; direct and indirect
transmission. Sometimes body surfaces of the clinical providers come into touching base
with patients, for example while taking blood pressure or pulse, touching the patients groin
twice for a few seconds then cleaning with soap and afterwards to manipulate a sterile foley
catheter can lead to Enterobactericeae being transmitted (Long, Prober & Fischer, 2017). In
Mary’s case, the microorganism that caused her condition was the bacteria Staphylococcus
aureus which is often a commensal organism on the skin and upper respiratory tract.
2.2 Name one exogenous source of contamination and discuss the mode of transmission from
the source to the new host. (5 marks)
The most common source of human infection is other humans. Some agents are more
transmissible than others, for example, measles. Outbreaks occur and human beings transmits
pathogens to others. An example of an exogenous mode of transmission is sexual

transmission of agents, for example, Neisseria gonorrheae. Others are HIV and Treponoma
pallidum, Chlamydia trachomatis. These agents may be transmitted sexually and they survive
in hosts as a result of killing of the white blood cells and weakening immunity, hence they
thrive in the body of the host. (Wright, 2013). Staphylococcus aureus can be carried on hands
by people like healthcare personnel and end up spreading to the patients. (Bush & Schmidt,
2018). In Mary’s case, the bacteria was possibly present on the glass that cut her, hence was
spread to her through the glass.
A study by the Centre of Health Protection (2017) shows that Methicillin-resistant
Staphylococcus aureus (MRSA) is mainly transmitted through contact with wounds, soiled
and discharge areas. Unhygienic, crowded conditions and places, close contact with people
or objects infected with the bacteria, breaks in the skin due to wounds or indwelling
catheters.
Outbreaks of MRSA have also been seen in communities and households. In a variety of
community based reservoirs including Sports clubs day care facilities, jails, schools and work
places. Within households, the risk of infections from one household member to another is
high. This is because of contact between people and contact with objects. ( Knox, Uhlemann
& Lowy, 2015)
3. Rationale for choices of antibiotics (Total 10 Marks)
3.1 Rationale for the stat dose of ceftriaxone administered IVI immediately. (3 marks)
A study by ISMP Canada (2016) shows that ceftriaxone is an antibiotic and for Mary’s
wound, it was used for completion. It fights staphylococcus aureus, which was the primary
microorganism affecting Mary’s wound. Ceftriaxone can be used on skin and skin structures,
based on susceptible organisms (West Suffolk NHS Foundation Trust, 2018).
3.2 Rationale for the oral cephalexin. (2 marks)
Research by Auro Pharma Inc (2017), shows that cephalexin is bactericidal. In Mary’s case,