Abstract
Purpose: :
Fluorescein and benoxinate solution in a multiple use bottle is an important clinical tool for diagnostics and tonometry measurement in ophthalmology clinics. However, this solution may also be the source for dissemination of ocular infections. Contamination of ocular solutions may occur due to rapid administration, poor patient cooperation and clinician distraction. We aimed to determine the rate of bacterial and fungal contamination of 5 mL multiple usage bottles of fluorescein 0.25% and benoxinate 0.4% solution after a single day of use in an ophthalmology outpatient clinic. We also calculated the average duration of a 5 mL solution.
Methods: :
This project is a prospective blinded study. One unopened bottle of fluorescein sodium 0.25% and benoxinate hydrochloride 0.4% solution was placed in every exam room of the University of Sherbrooke ophthalmology clinics at the beginning of the day. All staff members working in the clinics were unaware of the ongoing project to prevent any change in their usual practice. At the end of the clinical day, all bottles were collected, left at room temperature for less than 24 hours and sent for culture. Three drops from each bottle were put on each of five culture media: blood agar, chocolate agar, Brucella agar, Sabouraud agar and Thioglycolate broth. All media where immediately stored in an air oven at 35 degrees Celsius until being delivered to the microbiology laboratory for further analysis. All cultures were kept for at least one week of observation before being discarded.
Results: :
A total of 27 bottles were collected from nine ophthalmologists. All of the bottles had negative culture after one week of incubation. All physicians were unaware of the project at the time of sample collection and reported to have used this solution, on average, for 80% of their patients. Considering the average frequency of usage and the average number of patients seen per day, a 5 ml of this solution would last two and a half days.
Conclusions: :
The multiple use of a single bottle of Fluoresceine sodium 0.25% and Benoxinate hydrochloride 0.4% is safe on a 24 hours basis in regard of the bacterial and fungal contamination risk. To our knowledge, this is the largest in-use contamination experimentation for this solution. The safety profile over a longer period of utilization warrants further investigation.
Keywords: microbial pathogenesis: experimental studies