May 2008
Volume 49, Issue 13
ARVO Annual Meeting Abstract  |   May 2008
Bacterial Contamination of Multi-Use Eye Drop Tips in a Clinic Setting
Author Affiliations & Notes
  • E. K. Walsh
    New York Medical College, New York, New York
  • G. Zaidman
    New York Medical College, New York, New York
  • J. Geliebter
    New York Medical College, New York, New York
  • H. Gould
    New York Medical College, New York, New York
  • Footnotes
    Commercial Relationships  E.K. Walsh, None; G. Zaidman, None; J. Geliebter, None; H. Gould, None.
  • Footnotes
    Support  None.
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 1977. doi:
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      E. K. Walsh, G. Zaidman, J. Geliebter, H. Gould; Bacterial Contamination of Multi-Use Eye Drop Tips in a Clinic Setting. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1977. doi:

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: : In a clinical setting, most eye drops are dispensed from multi-dose, multi-patient bottles. This study will investigate the potential bacterial contamination of bottles of multi-use eye drops.

Methods: : Forty-seven opened bottles of eye drops were grouped according to type of drop: glaucoma (n=11), dilating (n=10), anti-inflammatory (n=10), anesthetic (n=10), and anti-bacterial (n=6). The bottles and their solutions were tested for bacterial contamination in 3 ways. First, a sterile cotton swab was moistened with sterile water and the tip was swabbed and cultured on a blood agar plate (GROUP 1). Second, the tip was sterilized with a 70% isopropanol swab, allowed to dry, and re-swabbed with a second new moistened cotton swab and cultured (GROUP 2). Third, 4 drops of solution from the bottle were dropped onto a dry sterile cotton swab and cultured (GROUP 3). Samples from 3 unopened bottles were cultured as a negative control. Bacterial growth was monitored daily for 3 days. A Gram stain of each colony was performed to aid in identification of any growing organisms.

Results: : Overall, 11 of 47 (23.4%) opened bottleshad bacterial growth-- 3/11 glaucoma drops, 3/11 dilating drops, 3/11 anti-inflammatory drops and 2/11 anesthetic drops. No growth was noted from anti-bacterial drops (0/6). All bacterial growth was from GROUP 1(Tip); no growth was noted from either GROUP 2 (Sterilized tip) or GROUP 3 (Drop only). Eight tips cultured one organism while 3 cultured multiple organisms. Of the 8 monocultures, 7 were various species of staphylococcus while, the other monoculture was a Gram positive rod, Bacillus subtilis. Of the 3 bottles with multiple organisms grown, 2 bottles produced 2 different species of staphylococcus. The last bottle with multiple species produced 2 different species of staphylococcus and one species of lactobacillus.

Keywords: cornea: clinical science • keratitis • antibiotics/antifungals/antiparasitics 

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