Infectious Conjunctivitis: Causes, Mechanism of Action of Gentamicin, Signs, and Infection Control

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1. Background of the case study (Total: 5 marks)
1.1 What is infectious conjunctivitis?
It refers to conjunctiva inflammation that is usually caused by bacteria or viruses.
According to Bullock and Manias (2017), conjunctiva could be infected by the bacteria and
viruses. swelling, discharge and reddening are some of the common signs and symptoms,
other individuals become very sensitive to light.
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, because it is non-spore forming, gram-negative bacterium and it is the causative
agent of Legionnaires disease (Norris, 2019). It thus suggests that the specific causative
bacteria agents to the infectious conjunctivitis cannot be the same as the causative for
legionellosis. The condition of the eye has the specific bacterial and viral agents that
affects it (Boland, Santall & Video Education Australasia, 2011).
Plasmodium ovale
Yes or no, with reason:
No, it is because infectious conjunctivitis is not caused by a plasmodium. Plasmodium
ovale is a group of causative agents of malaria and thus it is less likely to be the cause of
infectious conjunctivitis; it is only the specific viruses and bacteria that could cause the
condition of the eye.
Adenovirus
Yes or no, with reason:
Yes, it is because it is a common virus that infect the eye linings, airways and even lungs.
It also affects nervous system and urinary tract. It is well known as being the common
cause of fever, sore throats, diarrhoea and pink eyes (Craft & Gordon, 2019). Therefore, the

microorganism is likely to be the causative agent of the eye condition in question.
Staphylococcus aureus
Yes or no, with reason:
Yes, it is because the bacterium is well known for causing acute bacterial conjunctivitis
according to Lee and Bishop (2016). The bacteria are a gram positive and round shaped and
a member of the microbiota of the body and occasionally found in the upper respiratory
tract and on the surface of the skin.
2. Mechanism of action and adverse reactions (Total: 5 marks)
2.1 Describe the mechanism of action of gentamicin?
The drug is a bactericidal antibiotic that functions by binding the 30S subunit of the
bacterial ribosomes and thus impacting negatively the protein synthesis. The principal
mechanism of action is generally accepted to function through ablating the ribosomes’
ability to discriminate in appropriate transfer of RNA and messenger RNA interactions. On
a general scale, whenever incorrect pairing of tRNA and mRNA codon occurs at the
aminoacyl site of the adenosines ribosome 1492 and 1493 are exempted from the
interaction making them to retract thus, signalling the chromosome in rejecting
aminoacylate tRNA. However, when binding of gentamicin, a helix 44 of 16S rRNA occurs,
it then compels the adenosines to maintain the position that they always taking whenever
there is a proper match between aa-tRNA and mRNA (Marieb & Hoehn, 2019)
As a result, acceptance of the incorrect aa-tRNA occurs causing the ribosome to perform
synthesis of proteins with wrong amino acids strategically arranged throughout (an
approximate if every 1 in 500). The effect is that the non-functional, aggregated and
mistranslated proteins misfolded, ultimately causing death of the bacterium. Gentamicin is
believed to preclude ribosomes interactions with ribosome factors of recycling, making the
two subunits of the ribosomes stay complex even after completion of the translation of the
new proteins. The resultant pool of inactive ribosomes is unable to reinitiate ad translate
new proteins (Burchum & Rosenthal, 2019).