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Surface Carrier Testing of Hospital Antiseptics Against Candida parapsilosis from Healthcare Workers' Hands
Jenyffie Araújo Belizário1, Maria Eduarda Brites Jardine1, Gabrielle Lameado Pereira1
1Laboratory of Microbiology, University of Franca, Franca 14404-600, SP, Brazil.
Abstract:
Candida parapsilosis is a major cause of healthcare-associated infections due to its persistence on abiotic surfaces and efficient transmission via healthcare workers' hands. This study evaluated the antifungal efficacy and safety of clinically relevant antiseptics against 60 C. parapsilosis clinical isolates using a surface carrier test designed to simulate contamination and disinfection events on hospital surfaces. Antifungal activity was assessed by logarithmic reduction (log10) assays on surface carriers and by minimum inhibitory concentration (MIC) testing. Potential synergistic interactions between antiseptics and selected phytochemicals were investigated using checkerboard assays, and toxicity was evaluated in vivo using Caenorhabditis elegans. Surface carrier assays showed that 70% ethanol and 0.5% alcoholic chlorhexidine (CHG) achieved the highest fungicidal activity, with reductions of up to 5 log10 after 1 min exposure at 25 °C. Polyhexamethylene guanidine hydrochloride (PHMGH) displayed consistently low MIC values (0.4-0.9 ppm) and intermediate surface activity. CHG combined with eugenol or menthol produced strong synergistic interactions, reducing CHG MICs from up to 6250 ppm to as low as 20 ppm (>300-fold). Toxicity assays revealed a narrow safety margin for CHG, whereas PHMGH showed a more gradual concentration-dependent toxicity profile. These findings highlight clinically relevant differences in antiseptic performance and identify combination strategies that may reduce CHG exposure while maintaining antifungal efficacy.
Insights
This study assessed antiseptic efficacy against Candida parapsilosis, a common healthcare infection source. Ethanol and chlorhexidine (CHG) showed high fungicidal activity, with phytochemicals enhancing CHG safety and effectiveness.
Area of Science:
- Microbiology
- Infectious Diseases
- Public Health
Background:
- Candida parapsilosis is a significant cause of healthcare-associated infections.
- Its persistence on surfaces and transmission by healthcare workers facilitate spread.
- Effective disinfection strategies are crucial for infection control.
Purpose of the Study:
- To evaluate the antifungal efficacy and safety of clinically relevant antiseptics against Candida parapsilosis.
- To investigate synergistic interactions between antiseptics and phytochemicals.
- To assess the toxicity profiles of tested antiseptics.
Main Methods:
- Surface carrier tests simulating hospital surface contamination and disinfection.
- Logarithmic reduction (log10) assays and minimum inhibitory concentration (MIC) testing.
- Checkerboard assays for synergistic interactions and in vivo toxicity assays using Caenorhabditis elegans.
Main Results:
- 70% ethanol and 0.5% alcoholic chlorhexidine (CHG) demonstrated the highest fungicidal activity (up to 5 log10 reduction in 1 min).
- Polyhexamethylene guanidine hydrochloride (PHMGH) showed low MIC values (0.4-0.9 ppm) and moderate surface activity.
- Combinations of CHG with eugenol or menthol exhibited strong synergy, significantly reducing CHG MICs; CHG had a narrow safety margin, while PHMGH showed dose-dependent toxicity.
Conclusions:
- Clinically relevant differences exist in antiseptic performance against Candida parapsilosis.
- Combination strategies with phytochemicals can potentially reduce CHG exposure while maintaining efficacy.
- PHMGH presents a more favorable toxicity profile compared to CHG.
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