Related Experiment Video
Updated: Dec 23, 2025
A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection
Published on: February 28, 2019
Auranofin Rapidly Eradicates Methicillin-resistant Staphylococcus aureus (MRSA) in an Infected Pressure Ulcer Mouse
Haroon Mohammad1, Nader S Abutaleb1, Mohamed N Seleem2,3
1Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA.
Abstract:
Pressure ulcers (PUs) frequently occur in individuals with limited mobility including patients that are hospitalized or obese. PUs are challenging to resolve when infected by antibiotic-resistant bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA). In this study, we investigated the potential of repurposing auranofin to treat pressure ulcers infected with MRSA. Auranofin's in vitro activity against strains of S. aureus (including MRSA) was not affected in the presence of higher bacterial inoculum (107 CFU/mL) or by lowering the pH in standard media to simulate the environment present on the surface of the skin. Additionally, S. aureus did not develop resistance to auranofin after repeated exposure for two weeks via a multi-step resistance selection experiment. In contrast, S. aureus resistance to mupirocin emerged rapidly. Moreover, auranofin exhibited a long postantibiotic effect (PAE) in vitro against three strains of S. aureus tested. Remarkably, topical auranofin completely eradicated MRSA (8-log10 reduction) in infected PUs of obese mice after just four days of treatment. This was superior to both topical mupirocin (1.96-log10 reduction) and oral clindamycin (1.24-log10 reduction), which are used to treat infected PUs clinically. The present study highlights auranofin's potential to be investigated further as a treatment for mild-to-moderate PUs infected with S. aureus.
Insights
Auranofin effectively treats methicillin-resistant Staphylococcus aureus (MRSA) in pressure ulcers, showing superior results to current treatments. This repurposed drug offers a promising new option for infected pressure ulcers.
Area of Science:
- Microbiology
- Dermatology
- Pharmacology
Background:
- Pressure ulcers (PUs) are common in immobile individuals and difficult to treat when infected with antibiotic-resistant bacteria like MRSA.
- Current treatments for MRSA-infected PUs have limitations in efficacy and resistance development.
Purpose of the Study:
- To investigate the potential of repurposing auranofin as a treatment for MRSA-infected pressure ulcers.
- To evaluate auranofin's in vitro activity, resistance development, and in vivo efficacy against MRSA.
Main Methods:
- Assessed auranofin's in vitro activity against S. aureus (including MRSA) under various conditions (high inoculum, low pH).
- Conducted multi-step resistance selection experiments comparing auranofin and mupirocin.
- Evaluated the postantibiotic effect (PAE) of auranofin in vitro.
- Tested topical auranofin efficacy in a murine model of MRSA-infected pressure ulcers.
Main Results:
- Auranofin maintained in vitro activity against MRSA despite high bacterial loads and acidic conditions.
- Staphylococcus aureus did not develop resistance to auranofin after prolonged exposure, unlike rapid resistance to mupirocin.
- Auranofin demonstrated a significant long postantibiotic effect.
- Topical auranofin achieved complete MRSA eradication in mouse PUs within four days, outperforming mupirocin and clindamycin.
Conclusions:
- Auranofin shows potent in vitro and in vivo activity against MRSA in pressure ulcers.
- Auranofin's lack of rapid resistance development and superior efficacy make it a promising candidate for treating MRSA-infected PUs.
- Further investigation of auranofin for mild-to-moderate MRSA-infected pressure ulcers is warranted.
