Vaccine cures dangerous yeast infections in mice

By Julie Steenhuysen

CHICAGO (Reuters) - A vaccine helped mice fight off a life-threatening type of yeast infection, U.S. researchers said on Monday in a finding that holds promise for preventing this severe condition as well as pesky vaginal infections.

The yeast Candida albicans normally lives in the mouth, gastrointestinal tract and vagina without causing trouble but antibiotics or other drugs can cause an overgrowth.

When Candida organisms enter the blood, they can be disseminated throughout the body, causing severe illness.

"This is a life-threatening form of the disease," killing an estimated 70,000 to 100,000 people in the United States each year, said Jim Cutler of the Research Institute for Children at Children's Hospital in New Orleans, who worked on the vaccine.

"It has over the last 30 years very much taken off as a significant problem, especially in hospitalized individuals," Cutler said in a telephone interview.

He said certain hospital procedures, such as gastrointestinal surgery, put people at a higher risk for invasive candidiasis. And while antifungal drugs help, they do not work in 30 percent to 45 percent of patients, he said.

Cutler and colleagues thought a vaccine given ahead of immune-compromising treatments might help prevent some of these deaths.

They developed a synthetic vaccine made from the yeast that incorporates both a carbohydrate and a protein from the yeast cell, offering the immune system two potential targets.

The researchers gave mice three doses of the vaccine, and then challenged them with what is normally a lethal infection.

Mice that did not receive the vaccine died after 24 days, but the vaccinated mice got better.

"They recovered completely to the point where we can no longer detect the presence of the fungus in any of the tissues," said Cutler, who reported his findings in the journal Proceedings of the National Academy of Sciences.

He said they also tried the vaccine against a form of vaginal yeast infection and the antibodies protected these mice as well.

Cutler said the next step is to vaccinate rhesus monkeys and see if a serum made from their blood can help cure mice with invasive yeast infections.

If successful, Cutler thinks the vaccine might be used to reduce the risks of invasive candidiasis and might even help prevent vaginal yeast infections.

(Editing by Maggie Fox and Vicki Allen)