In vitro long-term exposure to chlorhexidine or triclosan induces cross-resistance against azoles in Nakaseomyces glabratus.

Summary

A high-throughput in vitro exposure platform showed that long-term chlorhexidine or triclosan exposure led to azole resistance in 50 N. glabratus isolates, associated with PDR1 and PMA1 mutations, while octenidine did not induce cross-resistance. Resistance to the antiseptics themselves did not become stable.

Key Findings

• Long-term exposure to chlorhexidine or triclosan induced azole resistance in 50 N. glabratus isolates, with mutations identified in PDR1 and PMA1.
• Stable resistance to the antiseptics themselves did not develop after prolonged exposure.
• Octenidine did not promote cross-resistance to azoles under the same conditions.

Clinical Implications

Consider limiting routine use of chlorhexidine and triclosan where alternatives (e.g., octenidine) are feasible, and strengthen surveillance for azole resistance in Candida/Nakaseomyces species, especially in high-exposure settings.

Limitations

• In vitro-only findings; clinical translatability and exposure conditions in vivo remain to be established
• Species-specific results; effects on other Candida species are not detailed in the abstract

Future Directions

Validate findings in clinical cohorts with antiseptic exposure histories, assess fitness costs and reversibility, and evaluate stewardship interventions substituting octenidine in high-use settings.