Evaluation of microbial contamination in multi-dose fluorescein eyedrops in a reference eye center

ABSTRACT Purpose: To analyze the presence of microorganisms in fluorescein eyedrops used in a reference eye center in Recife-PE. Methods: This real-life and masked study evaluated fluorescein eyedrops used at the Altino Ventura Foundation in May 2019. Cultures were performed according to exposure times; I) three eyedrop bottles were analyzed after one day of use, II) three eyedrop bottles after 4 d of use, III) three eyedrop bottles after 8 d of use, and IV) three unopened bottles used as control. Samples were collected from the bottle’s tip, instilled drop, and residual fluid. After incubation, all colonies were analyzed and identified through biochemical tests. Results: The contamination rate of the fluorescein eyedrop bottles in this study was 55.5% (5/9 vials). There was no contamination in the control group. The highest contamination was seen in one day exposed eyedrops, in 100% of the bottles. The bottle’s tip had a higher rate of contamination compared to the drop and residual fluid. Gram-positive bacteria were isolated in 7/27 (25.9%) samples. Growth of fungi or gram-negative bacteria was not observed. Conclusion: The identification of gram-positive bacteria predominantly on the tip of the fluorescein eyedrop bottles suggests inadequate handling as the main cause of contamination.