Purchase this article with an account.
Hsiao-sang Chu, Fung-Rong Hu, Chin-Tin Chen; Photodynamic antimicrobial chemotherapy for methicillin-resistant Staphylococcus aureus -in vitro, biofilm, and ex vivo bovine keratitis model. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4307.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate the efficacy of micelle encapsulated chlorin e6 (mCe6) photodynamic antimicrobial therapy (PACT) on methicillin-resistant Staphylococcus aureus (MRSA) infection.
Chlorin e6 was encapsulated into micelles by the reversed-phase evaporation method. 405nm purple laser with adjustable fluence rate was used as the light source. MRSA suspension (2×108/ml) was incubated with various concentration of mCe6, followed by exposure of light. Colony forming units (CFUs) of diluted suspensions were counted for survival assay after treatment. For biofilm growth, stainless steel mircodisc was incubated with MRSA suspensions (108/ml) over night. The microdiscs were washed and incubated with different concentration of mCe6, followed by exposure of light. The biofilm on the microdisc was removed by mechanical oscillation for survival assay after PACT. For keratitis model, fresh bovine eyes were inoculated with MRSA (100CFU/10μL) in superficial corneal stroma and incubated in moist chambers. Biomicroscopic examinations were performed 12 and 16 hours after infection. Twelve hours after infection, bovine eyes were divided into four groups: no treatment, treated with hourly topical vancomycin (50mg/ml)(V), treated with 10μL mCe6 (100mM) topically every 5 minutes for 30minutes, followed by exposure of light at a fluence rate of 35mW/cm2 for 10 minutes(P), combined mCe6 mediated PACT with hourly topical vancomycin (50mg/ml)(P+V). Four hours after treatments, the corneal buttons were trephined for tissue homogenization and bacterial survival assay.
mCe6 mediated PACT showed a dose-dependent inhibition on MRSA suspension and biofilm. Under the light dose of 10J/cm2, at a concentration of 1μM, mCe6 was able to decrease 5 log bacteria in suspension. Under the light dose of 20J/cm2, at a concentration of 100μM, mCe6 was able to decrease 2 to 3 log bacteria in biofilm. For ex vivo bovine keratitis model, compared with the control, the vancomycin treated)(V), and the mCe6-PACT treated(P) groups, significantly fewer CFUs were noted in the combined treatment group)(P+V).
This study demonstrated the effectiveness of mCe6-PACT against MRSA. mCe6 mediated PACT could be a potential alternative treatment for MRSA keratitis.
This PDF is available to Subscribers Only