Malassezia: a fungus among us

Hypopigmentation caused by Malassezia (Photo: astrium.com)

A group of clinical researchers from the School of Biochemistry and Pharmacy at the National University of Rosario received the Best Scientific Work Award for their work in the assessment of culture media for studies on Malassezia growth and drug sensitivity. The ceremony took place during the Argentine Meeting on Micology in Posadas, Misiones.

According to Silvana Ramadán, the researcher who presented the work, “I believe that more than the methodology applied, our dedication, the bench work and our efforts to obtain the yeast isolates were considered”.

Along with Silvana Ramadán, authors  Maximiliano Sortino , Lucía Bulacio, Clara López  and Laura Ramos were interested in a kind of yeast that produces human mycoses, known as Malassezia. Formerly known as Pitirosporum, name we have heard in many commercial ads refering to anti dandruff shampoos against Pitirosporum ovale, this fungus is currently considered to be the same as Malazzesia. This yeast species is very difficult to propagate since its nutritional requirements are very specific and heavily-dependent on lipids. At the same time, the development of appropriate culture media is absolutely neccesary if we are to determine this fungus sensitivity to different antifungal drugs used in the treatment of patients.

Malassezia is usually present on normal human skin (and in dogs) but under some conditions may overgrow leading to skin manifestations and folliculitis. In hospitalized patients, Malassezia may display a more agressive behaviour leading to catheter-associated sepsis, especially in those cases where patients receive lipid-based parenteral nutrition.

“When I was a student, Malassezia furfur was the only species we had knowledge of. Now, we know that there are more than 15 species and it is hard to distinguish between them, especially because they are hard to grow in regular culture media and also very difficult to maintain in the lab since they require lipid-rich media. That is the reason why these yeasts are found in patients with sebhorreic skin and in body areas such as chest and face”, added Ramadán.

Antifungal sensitivity tests are neccesary to determine drugs and concentrations required to treat patients. This becomes a problem when no standard methods are available to grow Malassezia in optimal conditions. The two methods employed by the researchers yielded results comparable to previously published data. The next steps include the standardization of the different variables as well as correlation studies between both techniques. The aim is to provide new approaches to determine antifungal resistance for Malassezia at the hospital and community levels.

Source:
http://www.unr.edu.ar/noticia/3738/premio-al-mejor-trabajo-cientifico-sobre-micologia-clinica/

Let there be (UV) light

Vinchucas (Triatoma infestans) are carriers of Trypanosoma cruzi, the parasite causing Chagas-Mazza disease, an endemic pathology affecting different countries in Latin America. Mainly affected areas in Argentina include the north and northwest parts of the country. Also known as American trypanosomiasis, the disease is one of Argentina’s main health problems for which no cure is available although different treatments have been developed to lessen its effects. Parasites may cause heart disease and lesions affecting the digestive and nervous systems and in view of the current status, prevention is key.

Now, a group of researchers at the Regional Center for Scientific Research and Technology Transfer (CRILAR) from the province of La Rioja, report the results of a study aimed at the early detection of vinchucas. Methods to clearly determine the risk of the spread of disease as well as the presence of these insects are crucial for the successful design and evaluation of programs to control the malady.
Researchers point to the use of ultraviolet (UV) light to expose vinchuca´s feces as an easy way for the early detection of these vectors. “Vinchuca detection through the use of UV light is based in the fluorescent properties of these insects’ droppings when exposed to that light wavelength”, said Silvia Catalá, researcher at the CRILAR and the paper’s main author (see Sources).

Vinchuca’s feces vary in color (yellow, black, white or colorless) and the study showed that, except when black, all other colors display different fluorescent intensities. Fluorescence is higher in more recent depositions and in materials such as ordinary and adobe bricks, wood, paper and plastic. Droppings on certain fabrics and cardboard showed weaker fluorescence. According to Catalá “if we consider brick and wood as the two most common materials found in humble rural homes, this technique would allow us for an efficient detection of these insects”. According to the paper, colorless urine can also be detected by this method.

The technique would also provide with a quick way for the early detection of vinchuca infestation, since it can estimate number of insects and date of depositions (fluorescence decreases over time).
Dr. Catalá indicated the existence of portable UV flashlights which are commercially available and would permit the early detection of vinchuca infestation before their number becomes harder to handle.

Sources:
www.agenciacyta.org.ar
Paper in Acta Tropica

The sooner the better: detecting hepatitis C and HIV

The research group (left to right): Taborda, Giri, Perez and Gardiol.

Current methods to screen blood donors include a questionnaire and tests to detect a disease. But all those precautions cannot rule out the existence of the so-called window period. This is the period of time during which no antibody against an infection can be detected. Considering the hepatitis C and Human Immunodeficiency viruses this is a worrying situation when we think that for 22 (HIV) or 69 days (HCV) a
person can be considered suitable as a donor while they are actually infected. That is why proper detection methods are key when a blood transfusion is required.

A group of researchers at the Institute of Molecular and Cell Biology in Rosario are currently working to develop a method that will allow the detection of genetic material from any of these viruses. Such material is already present in the blood right after the infection unlike antibodies, which appear several days after the event, originating the window period.

Researchers, who are also faculty members at the School of Biochemistry and Pharmacy, National University of Rosario, are currently conducting a pilot study at one of the local public hospitals. Depending on the results, authorities will be notified in order to consider a large-scale implementation of the new test.

Another advantage of the new analysis is that it will allow for the detection of HIV and Hepatitis C virus strains circulating in the region. This, in turn, will favor better detection methods and treatments. “Many molecular diagnostic systems use kits made in the USA and Europe and may not consider strains circulating in our country leading to inaccuracies when making a diagnosis”, explained Project Director Adriana Giri.

The research group is formed by Adriana Giri, Daniela Gardiol y Miguel Taborda (PhDs), PhD-student Germán Perez and the Hemotherapy Service at the Hospital Provincial del Centenario leaded by Dr. Marcela Ruzzini.

Source:
Distéfano, S. Diseñan un test para detección temprana de virus de Hepatitis C y HIV. www.unr.edu.ar. 06/27/2011. www.unr.edu.ar/noticia/3715/disenan-un-test-para-deteccion-temprana-de-virus-de-hepatitis-c-y-hiv