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Updated: Jul 20, 2026
In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells
Published on: May 16, 2011
[In vitro adherence of Staphylococcus epidermidis and Pseudomonas alcaligenes to intraocular lenses]
Patrícia Ioschpe Gus1, Jacobo Melamed, Afonso Barth
1Faculdade de Medicina, Universidade Luterana do Brasil, Porto Alegre, RS, Brazil.
Purpose:
To quantify and compare the in vitro adherence of Staphylococcus epidermidis and Pseudomonas alcaligenes to different intraocular lenses (IOLs).
Methods:
Fourteen intraocular lenses were used in the experiment. Four of polymethylmethacrylate (PMMA), four of silicone, four of hydrogel and two of acrylic. Eight intraocular lenses were placed in eight test tubes containing 4 ml of Pseudomonas alcaligenes suspension, and six intraocular lenses were placed in six test tubes containing 4 ml of Staphylococcus epidermidis suspension. The bacterial suspension used for adherence tests was 10(8) colony-forming units per milliliter (CFU/mL) which corresponds to 0.5 in the scale of McFarland. The lenses were incubated at 37 degrees for two hours. After this, intraocular lenses were removed from the test tubes and dried twice with the use of distilled and sterile water. The material was spread on blood-agar for cultivation at 35-37 degrees C and was evaluated every 24 hours up to 72 hours. In the samples where there was bacterial growth, the colonies were counted using the conventional laboratory methods. All assays were performed in duplicate.
Results:
Adherence of Staphylococcus epidermidis to PMMA intraocular lenses was lower than to hydrogel and silicone intraocular lenses. Adherence of Pseudomonas alcaligenes to hydrogel intraocular lenses was lower than to PMMA, acrylic and silicone intraocular lenses.
Conclusions:
Results suggest that in vitro adherence of Staphylococcus epidermidis and Pseudomonas alcaligenes to intraocular lenses is influenced by type of material of the lens and by microorganism species. Bacterial adherence may play a role in the pathogenesis of some forms of endophthalmitis after cataract surgery. More in vitro and clinical studies are necessary to elucidate the mechanisms by which Staphylococcus epidermidis and Pseudomonas alcaligenes cause endophthalmitis.
Insights
Bacterial adherence to intraocular lenses (IOLs) varies by IOL material and bacterial species. This finding is crucial for understanding endophthalmitis after cataract surgery.
Area of Science:
- Ophthalmology
- Microbiology
- Biomaterials Science
Background:
- Cataract surgery is a common procedure, and intraocular lenses (IOLs) are implanted to restore vision.
- Endophthalmitis, a serious intraocular infection, can occur post-surgery, with bacteria like Staphylococcus epidermidis and Pseudomonas alcaligenes being potential causative agents.
- The interaction between bacteria and IOL surfaces is a critical factor in the development of endophthalmitis.
Purpose of the Study:
- To quantitatively compare the in vitro adherence of Staphylococcus epidermidis and Pseudomonas alcaligenes to various intraocular lens (IOL) materials.
- To investigate how different IOL materials influence bacterial adhesion.
Main Methods:
- Fourteen IOLs made of polymethylmethacrylate (PMMA), silicone, hydrogel, and acrylic were exposed to standardized suspensions of Staphylococcus epidermidis and Pseudomonas alcaligenes.
- Bacterial adherence was assessed by culturing after incubation and quantifying colony-forming units (CFU/mL).
- All experiments were performed in duplicate to ensure reliability.
Main Results:
- Staphylococcus epidermidis showed lower adherence to PMMA IOLs compared to hydrogel and silicone.
- Pseudomonas alcaligenes exhibited lower adherence to hydrogel IOLs than to PMMA, acrylic, and silicone IOLs.
- These results indicate material-specific bacterial adhesion patterns.
Conclusions:
- The type of IOL material and the specific bacterial species significantly influence in vitro bacterial adherence.
- Bacterial adherence to IOLs may contribute to the pathogenesis of endophthalmitis following cataract surgery.
- Further in vitro and clinical research is needed to fully understand the mechanisms of bacterial endophthalmitis.
