New antiseptic capable of eliminating 99.9% of Candida parapsilosis cells

A 0.5% alcohol-based chlorhexidine antiseptic, combined with the natural organic compounds eugenol and menthol, can eliminate 99.9% of Candida parapsilosis cells. This fungus is one of the leading causes of infections in hospital settings, such as intensive care units (ICUs). 

During testing, the formulation was more effective at eliminating C. parapsilosis than 70% ethanol, a common alternative for this type of disinfection. The results were published in the journal Pathogens. The discovery is significant because C. parapsilosis is highly resistant to medications and biocidal products.

Typically, C. parapsilosis lives in the human body without causing harm. However, if it comes into contact with wounds, surgical incisions, or medical devices implanted in patients, such as catheters, it can cause serious infections. In hospitals, contamination can occur via the hands of healthcare professionals because the species forms a biofilm on surfaces.

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The research was supported by FAPESP and is led by Regina Helena Pires, a professor at the University of Franca (UNIFRAN) in the state of São Paulo, Brazil. Professor Pires collaborated with researchers from the Federal University of Uberlândia, the Institute of Tropical Medicine at the University of São Paulo’s Medical School (FM-USP), and the University of Minho in Portugal.

Drug-resistant

“These microorganisms are drug-resistant, and many end up resistant to antiseptics and disinfectants as well. That’s why it’s so important to develop a product that’s effective at eliminating this fungus. Furthermore, healthcare professionals need to sanitize their hands many times a day, and alcohol ends up drying out the skin a lot. The formulation we’re developing includes essential oil components precisely for that reason because these herbal ingredients also moisturize the skin,” Pires explains. 

Although 0.5% alcohol-based chlorhexidine is already used as an antiseptic for hand antisepsis before invasive procedures such as surgeries, this new formulation may be more widely adopted by healthcare professionals because it is not toxic to human skin.

Fungal samples

Fungal samples were collected from the hands of 60 healthcare professionals working in pediatric and oncology ICUs.

According to the professor, the tests were conducted using products that are part of routine hospital practice. In total, nine combinations of potential antiseptics were tested.

“Since C. parapsilosis adheres to both human skin and to plastics and surfaces, the results indicate that using combinations of compounds can increase effectiveness against the fungus,” says Pires. 

Next steps in the research

The research group has been working on this line of study since 2023. Currently, they are conducting various tests with antiseptics, which are products applied to surfaces such as hands, and disinfectants, which are intended for surfaces of equipment or objects. According to Pires, these studies may lead to the development of more potent and specific products for use in ICUs and operating rooms in the future.

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“We’re conducting tests on pieces of pig skin in the lab because it’s the closest thing we have to human skin. That part of the research is already in its final phase. In October [2026], one of the researchers will travel to Portugal to do new tests on different surfaces in partnership with researchers from the University of Minho. We’ll use scanning microscopy, for example, to see what happens to these fungal cells after applying the formulations being tested, and we’ll conduct immunofluorescence assays to determine how many cells were damaged after application,” the researcher explains.