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Published on: September 8, 2021
Analysis of the adaptation capacity of Staphylococcus aureus to commonly used antiseptics by microplate laser
1Department of Dermatology, University Medical Center Jena, Jena, Germany. C.Wiegand@med.uni-jena.de
Background:
Bacterial colonization and infection are important factors in compromised wound healing. Antiseptics have become an alternative for antimicrobial applications as antibiotic resistance is increasing; they have multiple targets with a broad spectrum of activity. Hence, the risk for developing resistance should be low. However, concerns have been raised that their growing use may result in bacteria that are less susceptible.
Methods:
The capacity of common antiseptics such as silver nitrate, polihexanide, octenidine, chlorhexidine and polyvinylpyrrolidone (PVP)-iodine to induce adaptation in a Staphylococcus aureus strain was analyzed in vitro using microplate laser nephelometry. S. aureus was repeatedly incubated with the respective half maximal inhibitory concentration (IC(50)) over a time period of 100 days. The influence of the continued treatment was determined by in situ monitoring of changes in the dose-response curves and calculation of the current IC(50) values for the substances tested.
Results:
During the experiment, S. aureus quickly adapted to high concentrations of the antibiotic mupirocin during repeated treatment. Moreover, a significant increase of the IC(50) for silver nitrate was observed over time. On the other hand, no significant difference was observed for polihexanide or chlorhexidine. While the IC(50) for octenidine was also found to increase significantly, although the change was only marginal, reiterated incubation with PVP-iodine led to a decrease in the IC(50).
Conclusion:
Repeated treatment of S. aureus with polihexanide, chlorhexidine, octenidine and PVP-iodine did not trigger bacterial adaptation to these substances.
Insights
Repeated exposure to common antiseptics like polihexanide and chlorhexidine did not lead to Staphylococcus aureus adaptation. This suggests these antiseptics remain effective against bacterial resistance in wound healing.
Area of Science:
- Microbiology
- Antimicrobial resistance
- Wound healing
Background:
- Bacterial colonization and infection impede wound healing.
- Increasing antibiotic resistance necessitates alternative antimicrobial strategies.
- Antiseptics offer broad-spectrum activity, but concerns exist regarding potential bacterial adaptation.
Purpose of the Study:
- To investigate the in vitro capacity of common antiseptics to induce bacterial adaptation.
- To assess the development of reduced susceptibility in Staphylococcus aureus upon repeated exposure to antiseptics.
Main Methods:
- Staphylococcus aureus was repeatedly incubated with the half maximal inhibitory concentration (IC50) of various antiseptics over 100 days.
- Microplate laser nephelometry was used to monitor changes in dose-response curves and calculate IC50 values.
- The study analyzed adaptation to silver nitrate, polihexanide, octenidine, chlorhexidine, and polyvinylpyrrolidone (PVP)-iodine.
Main Results:
- Staphylococcus aureus rapidly adapted to mupirocin, showing increased IC50 values.
- A significant increase in IC50 was observed for silver nitrate, indicating adaptation.
- No significant changes in IC50 were observed for polihexanide or chlorhexidine.
- Octenidine showed a marginal increase in IC50, while PVP-iodine demonstrated a decrease in IC50.
Conclusions:
- Repeated exposure of Staphylococcus aureus to polihexanide, chlorhexidine, octenidine, and PVP-iodine did not result in significant bacterial adaptation.
- These findings suggest that polihexanide, chlorhexidine, octenidine, and PVP-iodine may be reliable options for managing bacterial infections in compromised wound healing.
- Further research is warranted to confirm these in vitro findings in clinical settings.
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