Featured Research

from universities, journals, and other organizations

Soft Contact Lens Corneal Infections Fueled By Resistant Microbes

Date:
January 29, 2008
Source:
University Hospitals of Cleveland
Summary:
Researchers find lens care solutions are inadequately tested with an outdated and irrelevant fungus strain. New research shows that corneal infections associated with soft contact lenses are fueled and made resistant to treatment by the formation of a highly resistant structure of microbial cells held together with a glue-like matrix material. Scientists call this conglomeration of cells biofilms.

In 2006, Bausch & Lomb withdrew its ReNu with MoistureLoc contact lens solution because a high proportion of corneal infections were associated with it. Now in a new study from University Hospitals Case Medical Center, researchers show that these infections were fueled and made resistant to treatment by the formation of a highly resistant structure of microbial cells held together with a glue-like matrix material. Scientists call this conglomeration of cells biofilms.

"Once they live in that type of state, the cells become resistant to lens solutions and immune to the body's own defense system," said Mahmoud A. Ghannoum, Ph.D., director of the Center for Medical Mycology at University Hospitals Case Medical Center and senior investigator of the study which appears in the January 2008 issue of the journal Antimicrobial Agents and Chemotherapy. "This study should alert contact lens wearers to the importance of proper care for contact lenses to protect against potentially virulent eye infections," he said.

"Biofilms are a constellation of resistant organisms," Dr. Ghannoum said. They were suspected with the spate of infections in 2005-2006, but until this study, there were no data to prove this. This is the first in-vitro model for cornea keratitis infections caused by the fungus Fusarium, which was one of the main culprits in the ReNu with Moisture Loc cases, and another fungus called Candida albicans.

The researchers also discovered that the strain of fungus (ATCC 36031) used for testing the effectiveness of lens care solutions is a strain that does not produce biofilms as the clinical fungal strains do. Lens care solutions currently are tested against an old and rare genotype fungal strain obtained in the 1970s from a patient from Nigeria. The contact lens solutions, therefore, are effective in the laboratory, but fail when faced with strains in real-world situations. "The multipurpose contact lens solutions cannot kill these germs, to put it simply," said Dr. Ghannoum.

"We recommend that solutions be tested for biofilms produced by more recent clinical isolates," said Dr. Ghannoum. "One of the underlying reasons for ReNu with MoistureLoc not being effective against the outbreak of keratitis is that the solution is not effective against biofilms and the organisms contained in biofilms."

The researchers tested six kinds of contact lenses made by three different manufacturers and two lens care solutions (Bausch & Lomb's MoistureLoc and MultiPlus) against three fungal strains (two recent clinical strains and the one from the 1970s) of Fusarium and one strain of C. albicans.

Since biofilm contamination of contact lens cases is a common finding, and ReNu with MoistureLoc is ineffective against fungal biofilm, the industry must ensure that their multipurpose solutions are effective against biofilms, said Dr. Ghannoum. In the meantime, extreme caution must be taken to ensure the contact lens care case is not contaminated with biofilm.

Dr. Ghannoum recommends that soft contact lens wearers use only fresh lens care solution, not add fresh solution to old solution, a phenomenon known as topping off, and use solution by expiration dates written on the package. He also recommends a rub and rinse method, regardless of which cleaning or disinfecting solution used (which also is recommended by the Centers for Disease Control and Prevention). An additional preventative measure to prohibit the development of biofilms is to ensure that the bottle caps and tips of multipurpose solutions are clean.

The study involved researchers in the Center for Medical Mycology, Department of Dermatology, and Department of Ophthalmology and Visual Sciences at University Hospitals Case Medical Center and Case Western Reserve University in Cleveland. The strains of fungus tested in the study were obtained from patients with fungal keratitis at University Hospitals Case Medical Center, the Cleveland Clinic Foundation, and the American Type Culture Collection (Manassas, Va.). This work was supported by funding from the National Institutes of Health.


Story Source:

The above story is based on materials provided by University Hospitals of Cleveland. Note: Materials may be edited for content and length.


Cite This Page:

University Hospitals of Cleveland. "Soft Contact Lens Corneal Infections Fueled By Resistant Microbes." ScienceDaily. ScienceDaily, 29 January 2008. <www.sciencedaily.com/releases/2008/01/080128113204.htm>.
University Hospitals of Cleveland. (2008, January 29). Soft Contact Lens Corneal Infections Fueled By Resistant Microbes. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2008/01/080128113204.htm
University Hospitals of Cleveland. "Soft Contact Lens Corneal Infections Fueled By Resistant Microbes." ScienceDaily. www.sciencedaily.com/releases/2008/01/080128113204.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins