Pichia identified as Candida antagonist
BOSTON — Researchers have discovered that the fungus Pichia inhibits the ability of Candida to form biofilms in patients with HIV and also those who are healthy. According to Mahmoud Ghannoum, PhD, this finding may lead to the development of novel approaches to control Candida in those with HIV and other immunocompromised patients.
Ghannoum, director of the Center for Medical Mycology in the department of dermatology at Case Western Reserve University in Ohio, presented results at a press conference today.
"The purpose of doing our work was to try to understand whether there is a relationship between microbiota, fungi and bacteria with the disease process in the HIV setting," Ghannoum said. "We characterized, for the first time, the core mycobiome in the sample of bacteria and fungi present in HIV-infected patients and uninfected controls."
The researchers collected clinical data and medication information for 12 patients with HIV and 12 healthy participants; no clinical symptoms of disease in the mouth were noted.
Ghannoum and colleagues identified 14 core oral bacteriomes present in at least 20% of participants in both groups: Actinomyces, Granulicatella, Fusobacterium, Leptotrichia, Rothia, Neisseria, Haemophilus, Pasteurella, Porphyromonas, Prevotella, Gemella, Streptococcus and Veillonella. There was no significant difference in bacterium between the two groups. Core mycobiomes among HIV-infected patients included Candida, Penicillium, Alternaria, Epicoccum and Trichosporon; among healthy controls, the core mycobiomes were Candida, Penicillium, Pichia, Cladosporium and Fusarium.
They then examined the association between Candida colonization and members of the core oral mycobiome and core oral bacteriome. They found that a decrease in colonization by Pichia correlated with a simultaneous increase in Candida colonization. There was no association between Candida and core oral bacteriome. To validate this association, they examined the effect of Pichia supernatants on Candida biofilms; Penicillium, present in both groups, was used as a control.
In the presence of Pichia, Candida-produced biofilms were significantly reduced (P=.19) compared with Penicillium-treated and -untreated controls. Additionally, exposure to Pichia supernatant led to disrupted, thinner biofilms (29 mcm and 61 mcm thick, respectively; P=.032). - by Stacey L. Fisher
For more information:
- Ghannoum M. #784. Presented at: IDSA 49th Annual Meeting; Oct. 20-23, 2011; Boston.
Disclosure: Dr. Ghannoum reports no relevant financial disclosures.