The identification by Irish researchers of a new form of fungal infection which severely impairs HIV-infected and AIDS patients is leading to improved treatments and better quality of life for people with the disease, a conference in Dublin has been told.
A team headed by Prof David C. Coleman in the school of dental science and department of microbiology in Trinity College discovered a new form of yeast - also known as Candida - which exploits the patient's compromised immune system, causing severe mouth infections as it spreads to the body's food pipe.
Because they discovered a new species, they were allowed name it. "We called it after Dublin, using the Latin name; Candida dubliniensis," Prof Coleman told a Royal Irish Academy conference on how microbes respond to stress.
The discovery is prompting a reappraisal of drug treatments for HIV/AIDS infection, he said. Being a particularly insidious bug, because it develops resistance rapidly to a variety of anti-fungal drugs, early intervention is now being deployed in an attempt to identify it and treat it using alternative drugs which do not promote resistance. With this regime, patients are not subject to repeat infections usually associated with Candida.
The discovery is not only leading to reappraisal of treatments, but also giving new insights on how microbes cause disease and is fuelling renewed global interest in research into fungal diseases. The species is only one of a handful capable of causing disease in humans discovered over the past 100 years. In recognition of this, Prof Coleman yesterday received the RIA National Commission for Microbiology award for excellence in microbiological research. Since 1990, the group has used advanced DNA fingerprinting techniques to investigate the properties of oral Candida in Irish HIV-infected and AIDS patients. The team noticed a significant increase over a three year period of Candida organisms with "very unusual fingerprints", particularly from people experiencing repeated episodes of oral infection.
Other scientists believed it was a "weird form of Candida albicans". The genetic analysis of Prof Coleman, with Dr Derek Sullivan, however, revealed it as a new species found throughout the world. Why it is predominantly among HIV/AIDS patients is not completely understood, but there is strong evidence to suggest its ability to develop resistance to drugs "in a matter of days" could partly explain its recent emergence in humans.
By gaining clear insights into the operation of their stress response mechanisms, "we are becoming better able to impede or to assist microbes to our benefit", according to Prof Charles Dorman of Trinity College.
Dr Jay Hinton of Oxford University outlined how his research team had developed a system to identify the signals for "switching on expression of specific bacterial genes" as well as visualising genetic expression in individual cells through the use of a green fluorescent protein found in Aequorea jellyfish.
This technique is providing valuable insight into stress responses of E coli and salmonella bacteria and their relationship to human infection. While it requires a massive dose of salmonella organisms to cause infection, he believed it was not a case of "one gets lucky" and makes its way inside the body.
