A biofilm within a contact lens case can increase the risk of microbial keratitis and infiltrative keratitis (Szczotka-Flynn et al, 2010). Reusable contact lens wearers require lens care solutions to inhibit the growth of pathogens to decrease the risk of soft contact lens-related infections (Gabriel et al, 2018). Because bacterial biofilm formation on soft contact lenses increases the possibility of infectious eye diseases, and because biofilms are highly resistant to antibiotics (Artini et al, 2015), it is critical for soft contact lens care solutions to have the ability to reduce or prevent biofilm formation (El-Ganiny et al, 2017). Commercially available soft contact lens multipurpose solutions may be ineffective against biofilms (Kilvington et al, 2010).

There have been encouraging results with the development of new components and technologies for reducing microbial contamination of contact lenses and related products (Willcox et al, 2021). The majority of such studies have examined the effect of potential new disinfectants on microbes suspended in solution. There is little information regarding their ability to control microbe adhesion to contact lenses.

Super Foods and Plant Power

Allium sativum (garlic) is a food known for its immunomodulatory, antimicrobial, anti-inflammatory, antimutagenic, and antitumor properties (Donma and Donma, 2020). Cannabis oils are extracts from cannabis plants and contain cannabidiol (CBD) and delta-9 tetrahydrocannabinol (THC). Unprocessed, these oils contain the same active ingredients as the plants. The balance of compounds depends on the specific plants from which the oil is derived. Different options for the medical use of cannabis have been reported in the literature, among which are anti-inflammatory and antitumor effects as well as treatment of glaucoma (Novack, 2016).

One study evaluated two natural mixtures—Allium sativum fermented extract (BGE) and CBD—for their ability to inhibit/remove Pseudomonas aeruginosa biofilms on/from soft lenses (Di Onofrio et al, 2019). BGE and CBD were compared to a multipurpose soft lens care solution. Two different P. aeruginosa strains (ATCC 9027 strain and clinical strain) isolated from ocular swabs were tested and quantified. Both forms of P. aeruginosa generated biofilms. BGE at minimal inhibitory concentration (MIC) had inhibition percentages higher than 55% for both strains; CBD inhibited biofilm formation by nearly 70% (Di Onofrio et al, 2019).

The effect of BGE on microbial biofilm eradication on soft contact lenses at MIC was 45% eradication for P. aeruginosa ATCC 9027 and was 36% for P. aeruginosa clinical strain. With CBD, there was 24% biofilm eradication for both strains. For the soft lens care solution, these were 43% eradication for P. aeruginosa ATCC 9027 and 41% for P. aeruginosa clinical strain.

Synergistic combinations of antimicrobials have been proposed and recommended to eradicate biofilm-associated infections due to multi-resistant pathogens (Dosler et al, 2016). Fractional inhibitory concentration index values of test antimicrobials were determined to assess the type of antibiofilm interaction (synergistic, additive, or antagonistic) (Di Onofrio et al, 2019). In the Di Onofrio study, the test soft contact lens solution/BGE combination demonstrated synergistic antibiofilm efficacy against 69% of test bacterial isolates. The test soft lens solution/CBD combination demonstrated synergistic antibiofilm efficacy against 75% of test bacterial isolates. The possible mechanisms of the synergistic interactions of test soft contact lens solutions in combination with BGE and CBD is not understood at this time. Future studies are required and may provide insight into novel contact lens solutions that modulate biofilm formation. CLS

For references, please visit www.clspectrum.com/references and click on document #310.