Methods: Explants of porcine vaginal mucosa (PVM, 5 mm, full-thickness squamous epithelium) were infected with MRSA USA300 LAC strain (1 x 106CFU/explants). Following 2h infection, explants were treated with Betadine® Solution, 3M™ SNP, or Clorox Healthcare™ Nasal Antiseptic for 1 h or left untreated. Explants were washed with PBS + 2% mucin to mimic mucocilliary clearance and incubated at 37˚C for 1 h, 6 h, or 24 h. Bacteria were enumerated by transferring explants to neutralization broth, vortex mixing and plating. Data presented are M ± SEM, N ≥ 3, n=3.
Results: Treatment with 3M™ SNP, Betadine® Solution or Clorox Healthcare™ Nasal resulted in a 4.6 ± 1.9 log10, 4.8 ± 1.9 log10 or 3.1 ± 1.9 log10 reduction in MRSA (CFU/explants), respectively. All were significantly different from untreated control 1 h post-wash. 3M™ SNP had significant persistence at 6 h (4.4 ± 1.3 log10 reduction) and at 24 h. By 24 h, regrowth was observed in some treatment groups, however the antimicrobial effect of 3M™ SNP was significantly better than that of all other treatments (6.0 ± 1.7 log10 versus Betadine® Solution’s 1.9 ± 1.8 log10, or Clorox Healthcare™ Nasal’s 2.8 ± 1.8 log10 difference from untreated controls).
Conclusion: Iodine-containing formulations significantly reduce MRSA colonization of ex vivo mucosal tissue at 1 h; however, 3M™ SNP was persistent and superior to other iodine-containing formulations for reducing MRSA burden over 24h.
L. Breshears, 3M: Grant Investigator , Research support
T. Nordby, 3M: Employee and Shareholder , Salary
M. Hulse Stevens, 3M: Employee and Shareholder , Salary
M. Scholz, 3M: Employee and Shareholder , Salary