A new study has found that a naturally occurring ingredient is an effective disinfectant for contact lenses, which are worn by millions of people worldwide.
Microbial keratitis is one of the most serious potential complications for contact lens wearers. It is an infection of the cornea caused by bacteria; The most common is Pseudomonas aeruginosa.
Previous studies have shown that existing disinfectant solutions are not effective at preventing biofilms, which are clusters of bacteria attached to the surface of the lens.
Hydroquinine, an organic compound found in the bark of some plants, is known to have bactericidal activity against Pseudomonas aeruginosa and other clinically important organisms including Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae.
The team behind the discovery, from the University of Portsmouth in England and Naresuan and Pibulsongkram Rajabhat Universities in Thailand, have now explored the potential use of a versatile formulation containing hydroquinine as a disinfectant for contact lenses.
They tested the antibacterial, anti-adhesion and anti-biofilm properties of a hydroquinine-formulated multi-purpose solution (MPS) and then compared it with two commercial MPS; Opti-free replenishment and Q-I. The natural compound kills 99.9 percent of bacteria while disinfecting.
The paper, published in Antibiotics, says these findings could help develop novel antibiotics aimed at combating P. aeruginosa bacteria.
Commercially available disinfectant solutions, which are made from many chemicals, can sometimes cause reactions with painful side effects.
We hope that new agents made from natural products may be an excellent alternative to limit or reduce the risk of contact lens contamination.
It is exciting to see how this research has progressed; From discovery to exploring potential applications.”
Dr Robert Baldock, School of Pharmacy and Biomedical Sciences, University of Portsmouth
Up to 3.5 million corneal infections are reported annually and in extreme cases can result in permanent eye damage and vision loss. The risk of microbial keratitis doubles when someone wears contact lenses overnight and/or more than the recommended daily amount.
According to the World Health Organization (WHO), corneal blindness caused by microbial keratitis is emerging as a leading cause of visual impairment. The World Health Organization (WHO) has classified multidrug-resistant P. aeruginosa as a pathogen of greatest concern.
Drug-resistant bacteria occur in more than 2.8 million infections and are responsible for 35,000 deaths each year. Antimicrobial resistance occurs when microbes change over time and no longer respond to drugs, making infections difficult to treat.
Amoxicillin and trimethoprim are commonly prescribed antibiotics to which some strains of P. aeruginosa have become resistant.
Hydroquinine is already known to be an effective agent against malaria in humans, and is also being used in the Netherlands to treat nocturnal muscle cramps. Until now, very little has been investigated regarding its drug-resistant properties.
The lead author, Sattaparn Weuxiangsang from the Faculty of Allied Health Sciences at Naresuan University, is currently a visiting researcher at the University of Portsmouth.
He said: “Our preliminary findings suggest that soaking contact lenses in a multipurpose solution containing hydroquinine is likely to be helpful in preventing contamination and infection.
“However, further investigation is needed to determine whether hydroquinone also has adverse reactions or toxicity.
“We are continuing to test the compound in several cells, and so far, the results are really promising. This potential development could contribute to the creation of new disinfectants from natural products, effectively fighting P. aeruginosa infections and reducing cases of corneal infections.”
The paper concludes by recommending further research examining the effectiveness of hydroquinine with different contact lens materials and against other pathogenic microorganisms.
Weawsiangsang, S., etc (2024). Hydroquinine enhances the efficacy of contact lens solutions to inhibit Pseudomonas aeruginosa adherence and biofilm formation. antibiotics. doi.org/10.3390/antibiotics13010056.