Effectiveness of honey on Staphylococcus aureus and Pseudomonas aeruginosa biofilms

OBJECTIVES: Biofilms formed by Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) have been shown to be an important factor in the pathophysiology of chronic rhinosinusitis (CRS). As well, honey has been used as an effective topical antimicrobial agent for years. Our objective is to determine the in vitro effect of honey against biofilms produced by PA and SA. STUDY DESIGN: in vitro testing of honey against bacterial biofilms. METHODS: We used a previously established biofilm model to assess antibacterial activity of honey against 11 methicillin-susceptible SA (MSSA), 11 methicillin-resistant SA (MRSA), and 11 PA isolates. Honeys were tested against both planktonic and biofilm-grown bacteria. RESULTS: Honey was effective in killing 100 percent of the isolates in the planktonic form. The bactericidal rates for the Sidr and Manuka honeys against MSSA, MRSA, and PA biofilms were 63-82 percent, 73-63 percent, and 91-91 percent, respectively. These rates were significantly higher (P < 0.001) than those seen with single antibiotics commonly used against SA. CONCLUSION: Honey, which is a natural, nontoxic, and inexpensive product, is effective in killing SA and PA bacterial biofilms. This intriguing observation may have important clinical implications and could lead to a new approach for treating refractory CRS. (C) 2009 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.