Infectious Conjunctivitis: Causes, Symptoms, and Treatment

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1. Background of the case study (Total: 5 marks)
1.1 What is infectious conjunctivitis?
Infectious conjunctivitis is a clinical condition that leads to inflammation of the conjunctiva
and results in dilation of the conjunctival blood vessels resulting in symptoms of red eye,
purulent discharge and irritation caused by infection by bacteria or viruses. The symptoms
may continue in patient for less than two weeks and the clinical manifestations may differ
based on the type of causative organism. Some common types of infectious conjunctivitis
includes bacterial conjunctivitis, viral conjunctivitis, Chlamydia and non-infectious
conjunctivitis (Watson, Cabrera-Aguas & Khoo, 2018). In the case study, John, an 88
years old man has developed infectious conjunctivitis in his right eye. He has symptoms of
red and swollen eyes, purulent discharge and painful eye.
1.2 Of the four micro-organisms listed below, justify which one is more likely to be the cause
of John’s eye infection. Indicate why the other micro-organisms from the list are least likely
to cause the infection.
Legionella pneumophila
Yes or no, with reason:
No, Legionella pneumophila is least likely to be the cause of John’s eye
infection because this bacterium must be inhaled to cause disease and inhalation is not
the cause of conjunctivitis. Legionella mostly leads to Legionnaire’s disease, which is a
type of pneumonia resulting in lung inflammation and mostly caused by person-to-
person contact (Chahin & Opal, 2017). In John’s case, his infection was linked to
inflammation in the eyes and not lungs.
Plasmodium ovale
Yes or no, with reason:
No, plasmodium ovale is least likely to cause John’s conjunctivitis because it is a protozoa
and conjunctivitis is never caused by a protozoa. Plasmodium is a causative organism of
malaria and plasmodium ovale is never linked to any type of infective conjunctivitis (Lee &

Bishop, 2016).
Adenovirus
Yes or no, with reason:
No, adenovirus is least likely to cause conjunctivitis in John’s case because viral
conjunctivitis is associated with watery discharge from the eyes. However, in case of John,
his symptoms included purulent and sticky discharge from the eye. Therefore, John’s eye
infection due to adenovirus infection is not possible.
Staphylococcus aureus
Yes or no, with reason:
Yes, Staphylococcus aureus is most likely to be causing John’s eye infection
because his symptom of red eye and purulent discharge is seen in case of bacterial
conjunctivitis. Staphylococcus aureus is a common bacteria causing conjunctivitis and
John’s symptoms are similar to that of bacterial conjunctivitis infection (O’Callaghan,
2018).
2. Mechanism of action and adverse reactions (Total: 5 marks)
2.1 Describe the mechanism of action of gentamicin?
Gentamicin is a drug that is used to treat variety of bacterial infections. Gentamicin is an
aminoglycoside that exhibits its action by directly binding to the 30s protein subunit and
the 16s rRNA. The drug binds with the four nucleotides of 16S rRNA and amino acid of
S12, thus interfering with decoding site in the 16S rRNA of 30S subunit. It is the region
which interacts with the wobble based in the anticodon of tRNA and this disrupts the
initiation complex. Hence, misreading of RNA result in incorrect addition of amino acids
and instead various monosomes and toxic peptides are produced (Bullock & Manias,
2017). Therefore, by disrupting protein synthesis, the bacterium is killed and infection is
reduced in patient.
2.2 Name two adverse reactions of this drug?
Two adverse reactions associated with use of gentamicin include respiratory depression
and allergic reactions such as itching (Burchum & Rosenthal, 2019).
3. Physiological basis of signs (Total: 10 marks)
3.1 sign 1:

Red eyes
Explanation of this phenomenon:
The primary symptoms found for John was red eyes and this occurred because of the
inflammation of the conjunctiva due to bacterial infection. The infection irritates the blood
vessels of the conjunctiva resulting in swelling of the blood vessels. This process of
inflammation makes the eye appear reddish or pink (Craft & Gordon, 2019).
3.2 sign 2:
Thick, purulent and sticky discharge
Explanation of this phenomenon:
In patients with bacterial conjunctivitis, purulent and sticky discharge is seen because of
the infection with bacterial pathogens. Bacterial conjunctivitis results in severe purulent
discharge resulting in eye swelling, eye pain and palpation. Inflammation associated with
infection and dilation of the blood vessels of the eye is the main cause behind discharge
from the eye. Makker and Kaufman (2019) gives the evidence that purulent discharge
and oedema are suggestive of bacterial conjunctivitis.
3.3 sign 3:
Painful eye
Explanation of this phenomenon:
Painful eye is seen because of irritation and infection of the conjunctiva. Due to the
pathophysiological process associated with bacterial conjunctivitis, the conjunctiva
becomes infected and inflamed resulting in mild pain (Craft & Gordon, 2019).
4. Infection control issues (Total: 5 marks)
4.1 Issue 1:
Exposure to infected individual through poor hand hygiene
Discussion as to why this is an issue:
John is a resident of high dependency aged care facility where many health care staffs
and other patients reside. There is a risk of spread of conjunctivitis to staffs or patient
because of poor hand hygiene and transmission of infection from hand to eye contact.
John might be rubbing the eyes and then touching bed linens and towels. The hospital