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Microbial contamination of medications used to treat glaucoma
O Geyer1, E J Bottone, S M Podos
1Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
Aims:
A study was conducted to estimate the frequency of contamination of topical antiglaucoma medications used by asymptomatic patients.
Methods:
The drops and the bottle tips of 194 in use topical medications and the conjunctiva from 109 treated glaucoma patients were cultured.
Results:
Bacteria were recovered from 55 (28%) medications. The bottle tip was more frequently contaminated than the drops (p = 0.008). Gram positive organisms were cultured from 50 (91%) of 55 contaminated medications. Thirteen patients (12%) had the same microorganism recovered from the conjunctiva and from the contaminated medication. The frequency of contamination of medications increased with increasing duration of use. Bacterial contamination occurred in 19% of eyedrops less than 8 weeks old in contrast with 40% of bottles used for more than 8 weeks.
Conclusion:
Our data suggest that ocular medications to treat glaucoma frequently become contaminated with bacteria and that contamination is related to duration of use. We therefore recommend that opened topical antiglaucoma eyedrops should be replaced on a regular basis.
Insights
Topical antiglaucoma medications frequently become contaminated with bacteria, especially after 8 weeks of use. Regular replacement of opened eyedrops is recommended to prevent bacterial contamination and potential ocular infections.
Area of Science:
- Ophthalmology
- Microbiology
Background:
- Glaucoma is a leading cause of irreversible blindness worldwide.
- Topical antiglaucoma medications are the mainstay of treatment.
- Contamination of ophthalmic solutions can lead to ocular infections.
Purpose of the Study:
- To determine the frequency of bacterial contamination in topical antiglaucoma medications.
- To investigate the relationship between medication usage duration and contamination.
- To assess the potential for microbial transfer from medication to the ocular surface.
Main Methods:
- Bacterial cultures were performed on 194 in-use topical glaucoma medications (drops and bottle tips).
- Conjunctival cultures were obtained from 109 glaucoma patients using these medications.
- Statistical analysis was used to compare contamination rates and identify risk factors.
Main Results:
- Bacteria were recovered from 28% of the medications.
- Bottle tips showed higher contamination rates than the drops.
- Medication contamination increased significantly with longer duration of use, with 40% of bottles used over 8 weeks being contaminated.
- 12% of patients had matching microorganisms found in both the medication and on their conjunctiva.
Conclusions:
- Topical antiglaucoma medications are frequently contaminated with bacteria.
- Duration of use is a significant factor in medication contamination.
- Opened antiglaucoma eyedrops should be replaced regularly to minimize contamination risk and prevent ocular infections.