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Published on: April 8, 2013
Low pH nasal rinse solution enhances mupirocin antimicrobial efficacy
K Hon1, S Liu1, C Cooksley1
1Department of Surgery-Otolaryngology Head and Neck Surgery, Basil Hetzel Institute for Translational Health Research, Central Adelaide Local Health Network, Woodville South, Australia; Adelaide Medical School, The University of Adelaide, Adelaide, Australia.
Background:
Chronic rhinosinusitis (CRS) is a common condition negatively impacting a patient's quality of life. It has been hypothesized that bacterial biofilms are involved in the pathogenesis of CRS due to their persistence and difficulty to eradicate with conventional antibiotic therapy. Hence, the topical delivery of antibiotics via nasal rinse solution has gained a lot of attention due to the ability to deliver higher local concentrations, with less systemic absorption and side effects. This study investigates the efficacy of mupirocin dissolved in the 3 most commonly used sinus rinses in Australia Neilmed (isotonic saline), Flo Sinus Care (sodium chloride, sodium bicarbonate, potassium chloride, glucose anhydrous and calcium lactate and Pentahydrate) and FloCRS (sodium chloride, potassium chloride and xylitol).
Methods:
Planktonic and biofilm cultures of S. aureus (ATCC25923, 2 methicillin-resistant S. aureus (MRSA) (C222 and C263), and 2 methicillin-susceptible S. aureus (MSSS) (C311 and C349) clinical isolates) were treated with mupirocin dissolved in three sinus rinses (Neilmed, Flo Sinus Care and FloCRS with different pH). To establish whether pH was a significant factor in determining antibiotic activity, experiments with Flo CRS were performed both at pH 5.64 and elevated pH 7.7. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for planktonic cells. The biofilm biomass and metabolic activity were assessed by using crystal violet assay and alamarBlue assay respectively.
Results:
The combination of mupirocin in low pH (pH 5.64) sinus rinse (FloCRS) had the highest efficacy in reducing the growth of S. aureus in both the planktonic and biofilm forms. Mupirocin diluted in FloCRS (pH 5.64) showed a significantly higher reduction in both biomass and metabolic activity than that was observed when mupirocin was diluted in Neilmed, Flo Sinus Care or FloCRS (pH 7.7).
Conclusion:
The choice of irrigant solution for topical mupirocin delivery appears to be important for antimicrobial activity. The delivery of mupirocin via low pH FloCRS could be useful in eliminating S. aureus biofilms present on the sinus mucosa of patients with CRS.
Insights
Topical mupirocin in low pH sinus rinse effectively reduced Staphylococcus aureus biofilms. This finding is crucial for treating chronic rhinosinusitis (CRS) and improving patient quality of life.
Area of Science:
- Microbiology
- Pharmacology
- Otolaryngology
Background:
- Chronic rhinosinusitis (CRS) significantly impacts patient quality of life.
- Bacterial biofilms are implicated in CRS pathogenesis due to antibiotic resistance.
- Topical antibiotic delivery via nasal rinse offers localized treatment with reduced systemic effects.
Purpose of the Study:
- To investigate the efficacy of mupirocin delivered via common Australian sinus rinse solutions.
- To assess the impact of different sinus rinse formulations and pH on mupirocin's antimicrobial activity against Staphylococcus aureus.
- To determine the optimal conditions for eradicating S. aureus biofilms in the context of CRS treatment.
Main Methods:
- Evaluated planktonic and biofilm cultures of S. aureus, including methicillin-resistant (MRSA) and susceptible strains.
- Tested mupirocin efficacy in Neilmed, Flo Sinus Care, and FloCRS (at pH 5.64 and 7.7).
- Determined Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC); assessed biofilm biomass and metabolic activity.
Main Results:
- Mupirocin in low pH (5.64) FloCRS demonstrated superior efficacy against S. aureus biofilms and planktonic forms.
- Significantly greater reduction in biofilm biomass and metabolic activity was observed with mupirocin in low pH FloCRS compared to other rinses.
- The pH of the sinus rinse solution was a critical factor influencing mupirocin's antimicrobial effectiveness.
Conclusions:
- The choice of irrigant solution is critical for the antimicrobial efficacy of topical mupirocin.
- Low pH FloCRS is a promising vehicle for delivering mupirocin to eliminate S. aureus biofilms in CRS patients.
- This approach may enhance treatment outcomes for chronic rhinosinusitis by targeting persistent bacterial biofilms.
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