Fungal Infection Test Measures Gene Response

A test being developed will measure how a patient's genes respond to fungal infections. The test will be suitable for very sick or immunocompromised patients, particularly critical care patients.

The early gene-expression test for the fungal pathogen Candida was demonstrated in mice by scientists at Duke University's Institute for Genome Sciences & Policy (Durham, NC, USA). The scientists are gathering human specimens to devise a similar test to be used in humans.

The scientists performed an analysis of gene expression in blood samples of mice that were exposed to Candida albicans and a group of healthy control mice. They studied genes associated with immune response and found 20 sets of 60-80 genes were expressed together. One group of genes in particular distinguished the infected samples from the control samples.

Data were combined from the C. albicans group with data from a group of mice infected with Staphylococcus aureus. Two groups of genes were identified that could distinguish between the three groups of mice (healthy, those with candidemia and those with a staph. infection).

Candidemia in humans often has similar symptoms to other serious bloodstream infections. Discriminating between a bloodstream fungal infection and a bacterial infection using blood culture tests can take 48-72 hours and the results are not always reliable.

"This study provides the basis for development [of] a blood-gene expression test in humans to detect a life-threatening infection earlier than can be done using currently available methods," said Duke University's Prof. Geoffrey Ginsburg, senior author of the study.

People most at risk for Candidemia include patients hospitalized in intensive care units (ICUs), those after abdominal surgery, receiving antibacterial therapies, with central line catheters, and those who are immunosuppressed.

Duke University's scientific team considers the findings as the first step in the production of gene-expression signatures. As Prof. Ginsburg commented, ''This work is also part of a portfolio of blood gene-expression-based tests we are developing to detect viral, bacterial and now fungal infections that will lead to more precise diagnosis and more appropriate therapies for infectious disease."

The findings appeared in the March 3, 2010 edition of the journal Science Translational Medicine.

Related Links:
Duke University's Institute for Genome Sciences & Policy