Cryptococcus infections misdiagnosed in many AIDS patients
Most AIDS patients, when diagnosed with a fungal infection known simply as cryptococcosis, are assumed to have an infection with Cryptococcus neoformans, but a recent study from Duke University Medical Center suggests that a sibling species, Cryptococcus gattii, is a more common cause than was previously known.
The difference between these strains could make a difference in treatment, clinical course, and outcome, said Joseph Heitman, M.D., Ph.D., senior author of the study and chair of the Duke Department of Molecular Genetics and Microbiology.
The study was published Sept. 1 in PLoS Pathogens.
The study emphasizes that health professionals need more careful recording of the cryptococcal species to understand different clinical courses and possibly to change treatment strategies.
Researchers at Duke University Medical Center discovered that in the Los Angeles area, over 12 percent of AIDS patients diagnosed with Crypotococcus were infected with C. gattii, much higher than earlier studies, suggesting only about 1 percent have C. gattii. The researchers based these figures on molecular testing of fungal DNA barcodes.
This discovery comes at the same time as a C. gattii outbreak is expanding in the Pacific Northwest, spreading southward from Vancouver, British Columbia, through Washington, Oregon, and into northern California. Molecular testing is helping both health officials and scientists gain a picture of how a formerly tropical fungus could find new territory, in temperate climates, for infection.
"Importantly, we found that isolates causing the outbreak and those infecting AIDS patients are completely different (VGII vs. VGIII)," said co-lead author Edmond Byrnes, Ph.D., a recently graduated student in the Heitman laboratory.
Wenjun Li, Ph.D., also a co-lead author and researcher in the Heitman laboratory, noted that, based on the fungal isolate samples taken from patients, those with C. gattii may experience resistance to the commonly used "azole" drugs that combat fungal infections, and clinicians might be better aware of potential treatment problems if they knew the species.
Because cryptococcal strains are responsible for over 620,000 deaths annually and responsible for one-third of all AIDS deaths, this species distinction may be of public health importance.
"There may be an unrecognized health burden in AIDS patients attributable to C. gattii rather than C. neoformans," Heitman said.
He said that while a simple test is all that is needed to distinguish the two strains, "few clinical microbiology labs or hospitals, even in developed countries, are equipped to distinguish C. neoformans from C. gattii."
Heitman said that he doesn't believe that there is any human-to-human transmission of C. gattii, but rather, patients are being exposed in the environment. For example, one AIDS patient from San Diego had an isolate that was traced back to a type of tree, which is a common place to find C. gattii, in Australia and elsewhere.
"This study clearly illustrates that AIDS patients in certain areas of the world might be infected by two different cryptococcal species," said John R. Perfect, M.D., professor of medicine at Duke University Medical Center. "Although the outcome of infection in comparison between the two species remains uncertain, this study shows that we need to carefully control for potential differences and study them further."
Medical management might be more complicated for C. gattii compared to C. neoformans, including the possibility of azole drug resistance and the formation of cryptococcomas in the central nervous system that can be difficult to treat and that cause abscesses. "Based on the prevalence we found, it makes sense to pursue further clinical studies, not just to find out the species, but also the molecular type, so we can learn all we can about how this pathogen is travelling and evolving," Heitman said.
Provided by Duke University Medical Center
- New strain of virulent airborne fungi, unique to Oregon, is set to spread Apr 22, 2010 | not rated yet | 0
- Tiny molecules protect from the dangers of sex Nov 15, 2010 | not rated yet | 0
- GE eucalyptus tree investigation urged Jun 15, 2007 | not rated yet | 0
- Unexpectedly high rate of multiple strains in fungal infection May 19, 2010 | not rated yet | 0
- Tiny fungi may have sex while infecting humans Oct 30, 2008 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
The integration of mental health interventions into HIV prevention and treatment platforms can reduce the opportunity costs of care and improve treatment outcomes, argues a new Policy Forum article published in this week's ...
HIV & AIDS 2 hours ago | not rated yet | 0
(AP)—The decade-old law that transformed the battle against HIV and AIDS in developing countries is at a crossroads. The dream of future generations freed from the epidemic is running up against an era ...
HIV & AIDS 15 hours ago | not rated yet | 0
The hunt for an HIV vaccine has gobbled up $8 billion in the past decade, and the failure of the most recent efficacy trial has delivered yet another setback to 26 years of efforts.
HIV & AIDS May 19, 2013 | 5 / 5 (1) | 0
Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.
HIV & AIDS May 18, 2013 | 5 / 5 (2) | 0
Researchers at the University of Cincinnati (UC) have found that incorporating a peer-referral program for HIV testing into emergency departments can reach new groups of high-risk patients and brings more patients into the ...
HIV & AIDS May 17, 2013 | not rated yet | 0
An experimental sleeping pill from US drug company Merck is effective at helping people fall and stay asleep, according to reviewers at the US Food and Drug Administration, which could soon approve the new drug.
1 hour ago | 5 / 5 (1) | 0
(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...
8 hours ago | 4 / 5 (4) | 0 |
Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May ...
2 hours ago | 5 / 5 (3) | 0 |
(Medical Xpress)—Despite spending billions of dollars on research and development, drug companies have been unable to come up with effective treatments for dementia and Alzheimer's Disease (AD). Now, A. ...
6 hours ago | 4.8 / 5 (6) | 0 |
A drug commonly used to treat depression and anxiety may improve a stress-related heart condition in people with stable coronary heart disease, according to researchers at Duke Medicine.
3 hours ago | not rated yet | 0 |
The gap between life expectancy in patients with a mental illness and the general population has widened since 1985 and efforts to reduce this gap should focus on improving physical health, suggest researchers in a paper ...
1 hour ago | not rated yet | 0