Topical Ocular Anesthetics Harbour Clinically Important Microbes

Kyei S 1*, Appiah E 2, Ayerakwa AE2, Antwi BC2, Kwarteng AM3

1. Department of Optometry and Vision Sciences, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana.
2. Department of Biomedical Sciences, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
3. Discipline of Optometry, College of Health Sciences, University of KwaZulu-Natal, South Africa.
Corresponding Author: Dr Samuel Kyei. Email: Phone: +233243309718


Purpose: The study was to determine clinically important microbial contaminants of topical ocular anaesthetic medications used in eye centres in Ghana.

Methods: A cross-section of eye clinics were sampled for the topical ocular anaesthetic agents. Standard laboratory procedures and protocols were observed in culturing the samples on different Agars. Microscopy and various biochemical tests were performed to identify microbial species.  Antimicrobial susceptibility tests were also performed to ascertain the clinical importance of the isolated microbes.

Results: A total of 27 anaesthetic agent were obtained (which consisted of 15 Proparacaine and 12 Amethocaine), from which 87 bacteria were isolated which included Bacilli spp. 26(29.89%), Coagulase Negative Staphylococci spp. 17(19.54%), Moraxella spp. 17(19.54%), Staphylococcus aureus 8(9.19%), Streptococcus spp. 3(3.45%), Klebsiella spp. 3(3.45%), Pseudomonas spp. 1(1.15%), Proteus spp. 7(8.05%), Escherichia coli. 2(2.30%), and Shigella spp. 3(3.45%). There were 22 isolated fungal contaminants mainly Penicillium spp. 7(31.82%), Cephalosporium spp. 5(22.73%), Aspergillus spp 4(18.18%), Cercospora spp. 2(9.09%), and Cladosporium spp. 4(18.18%). The anaesthetic agent with the most bacterial contamination was Proparacaine 44(50.57%) followed by Amethocaine 43(49.43%). Also, both agents were equally contaminated with fungus 11(50.0%) in each. Gentamicin was the only antibiotics that showed 100% activity against all the bacterial isolates. Fungal contaminants were more susceptible to Ketoconazole as compared to Fluconazole (p≤0.05).

Conclusion: Topical ocular anaesthetic preparations used in clinical settings in  Ghana are contaminated with clinically important microbes as the isolated bacteria were susceptible only to Gentamicin and fungi to Ketoconazole and Fluconazole.

Keywords: Anesthetics, Ocular infections, Amethocaine, Proparacaine

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