The in-vitro activity of povidone-iodinecream against Staphylococcus aureus and its bioavailability in nasal secretions

J Hosp Infect. 2000 Jul;45(3):198-205. doi: 10.1053/jhin.2000.0733.


Due to the emergence of mupirocin-resistance in some epidemic strains of methicillin resistant Staphylococcus aureus (EMRSA) and the appearance of EMRSA with intermediate resistance to vancomycin, we evaluated the in-vitro activity of 5% povidone-iodine ('Betadine') cream as a possiblealternative to mupirocin for the elimination of nasal carriage of S. aureus. As judged by enrichment culture, povidone-iodine was bactericidal against three mupirocin-sensitive strains of S. aureus from nasal carriers, and against mupirocin-resistant and -sensitive strains of EMRSA types 3, 15 and 16, after incubation with povidone-iodine for 1.0 min at 32 degrees C. Mupirocin nasal ointment did not prevent growth after 180 min incubation. In a quantitative suspension test, 1:100 dilution of povidone-iodine cream completely eliminated an inoculum of 10(8)cfu/mL of all nine test organisms after incubation at 32 degrees C for 1.0 min, and 1:1000 dilution reduced cfu, by a factor of 10(5). After direct inoculation of the povidone-iodine cream to give 10(5)cfu/g, none of the test strains were recoverable after 30 s, giving a killing rate of approximately 10(4)cfu/s; for mupirocin nasal ointment, the maximum reduction of mupirocin-sensitive strains was ten fold after 3 h. Povidone-iodine activity was not detectable in sensitivity-testing agar, although 0.025% of povidone-iodine was detectable in a 15% nutrient strength tryptone soya agar. Using this minimal medium, the addition of nasal secretions (from any of 11 samples) reduced the activity of povidone-iodine by 80-90%, but mupirocin activity was unaffected. One millilitre of nasal secretions inactivated the equivalent of approximately 22.5 mg of povidone-iodine. These results suggest that povidone-iodine cream may have a role in the prevention of colonization and infection caused by MRSA, including mupirocin-resistant strains.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Anti-Infective Agents, Local / pharmacokinetics
  • Anti-Infective Agents, Local / pharmacology*
  • Biological Availability
  • Carrier State
  • Drug Resistance, Microbial
  • Humans
  • Microbial Sensitivity Tests
  • Mupirocin / pharmacology
  • Nasal Mucosa / metabolism
  • Nose / microbiology
  • Povidone-Iodine / pharmacokinetics
  • Povidone-Iodine / pharmacology*
  • Staphylococcal Infections / prevention & control
  • Staphylococcus aureus / drug effects*


  • Anti-Bacterial Agents
  • Anti-Infective Agents, Local
  • Povidone-Iodine
  • Mupirocin