Microbial contamination of multiple‐use bottles of fluorescein ophthalmic solution

Abstract

Background

The contamination of ophthalmic solutions in ophthalmic practices remains an important cause of a myriad of secondary eye infections and a source of aggravation of ocular disorders such as corneal ulcers and keratitis. The aim of this study was to investigate the possible microbial contamination of fluorescein sodium dye solutions used in eye clinics in Ghana.

Methods

Fluorescein sodium solutions were collected from various eye clinics in Ghana. Twenty‐one samples of multiple‐use fluorescein ophthalmic solutions were collected from various regions in Ghana. Eighteen unopened bottles yet to be used were also collected to serve as controls from the same facilities. The solutions were inoculated in different culture plates (blood agar, MacConkey agar, Sabouraud dextrose agar and plate count agar). The resulting microbial growth was identified using standard microbial identification techniques. Susceptibility tests were performed to ascertain the clinical importance of the organisms identified.

Results

Positive cultures were recorded for all 21 multiple‐use bottles (in‐use) collected, but there were no positive cultures for the unopened bottles (yet to be used). Six different genera of bacteria were identified from fluorescein solutions, including resistant strains of Staphylococci spp., Bacillus spp., Klebsiella spp., Pseudomonas spp., Haemophilus spp. and Bordetella spp. Pseudomonas spp. were the most common bacterial contaminants. For fungi contaminations, Aspergillus spp., Penicillium spp. and Cladosporium spp. were isolated. The most common fungal contaminants were Aspergillus spp.

Conclusions

Multiple‐use bottles of fluorescein solution used in eye clinics in Ghana were contaminated with clinically important strains of bacteria and fungi.

Key words:

• corneal ulcer
• fluorescein
• keratitis
• Pseudomonas spp.
• resistant strains

ACKNOWLEDGEMENTS

The authors are grateful to Francisca Akpene and Sandra Freda Wood for proofreading the manuscript.

Supporting information

Additional supporting information may be found in the online version of this article at the publisher’s website:

Figure S1. Plates of cultures of multiple‐use bottles of A: fluorescein solution on blood agar; B: fluorescein solution on plate count agar (PCA); C,D: fluorescein solution on Sabouraud; and D: control (unopened fluorescein).

Figure S2. A: Gram‐positive cocci bacteria viewed under ×100 lens (oil emersion); B: Gram‐negative bacillus (rod) visualised under the oil emersion lens of a light microscope; C: filamentous fungi; and D: a yeast‐like structure. Both fungi were stained with lactophenol blue and viewed under microscope with a magnification of ×40.