Antimicrobial activity of microparticles loaded with biocide precursors against MRSA and carbapenem-resistant E coli.

Adrian Fellows1,2,2

1Gama Healthcare Ltd

2AGA nanotech Ltd

3Gama Australia Pty. Ltd

Introduction: The development of antibiotic-resistance requires new therapeutic approaches. We evaluated the antimicrobial activity of microparticles loaded with biocide precursors against MRSA and CREC.

Methods: Sodium percarbonate and tetraacetylethylenediamine (are precursors for hydrogen peroxide (H2O2) and (PAA), were loaded onto polymer microparticles. Time-kill studies were performed using aqueous suspensions of loaded microparticles in contact with suspensions of MRSA and E. coli, varying the hydration time of the microparticles and contact time with the bacterial suspension. Hydration time was varied to test whether the antimicrobial activity of the microparticles would be sustained in vivo.

Results: MRSA and E. coli titres of ~6.0 log10 cfu were reduced to below the detection limit (10cfu) within 6 hours of contact when exposed to microparticles loaded with TAED and SP. Antimicrobial activity of the microparticles continued when hydration time was 1, 3 and 7 days, with a reduction in the inoculum challenge occurring within 18 hours. At 14 days, the microparticles continued to display antimicrobial activity (~2 log10 cfu and ~1 log10 cfu reductions for MRSA and E. coli bacteria, respectively) after 18 hours contact time.

Conclusion: The biocidal activity of TAED and SP is attributed to the formation of PAA via the reaction of the acyl group in TAED with the hydrogen peroxide from SP. The microparticles exhibited bactericidal activity over extended periods of hydration prior to exposure against two key MDRO pathogens. The controlled delivery of oxidative biocides offers the possibility of new therapeutic products to combat infection without the use of antibiotics.