Squalamine ointment for Staphylococcus aureus skin decolonization in a mouse model

Abstract

Objectives: Staphylococcus aureus colonization of the skin and the nostrils remains a major cause of surgicalsite infections despite preoperative and preventive procedures. To date, many compounds have been used for S. aureus decolonization, including mupirocin ointments and antiseptics, with variable results. The emergence of mupirocin-resistant S. aureus strains has led to the search for new antimicrobial agents specifically for S. aureus decolonization. In this work we evaluated squalamine and related parent-derived ointments (1%) as potential new compounds for S. aureus decolonization in a new mouse model. Methods: We report the development and application of squalamine and related parent-derived ointments in a new mouse skin model. After skin shaving, mice were colonized with an S. aureus suspension that was calibrated to 104-106 cfu/mL. The remaining bacterial load was monitored for 2 days after a single application of squalamine by spreading. Results: We found that S. aureus colonization of the skin was stable for at least 2 days before it was naturally eliminated. Using this model we found that squalamine ointment (1%) could reduce S. aureus viable cells by up to 4 log with a single, 1 h application of ointment, whereas mupirocin application reduced viable cell numbers by only 1.3 log during that same time (P < 0.05). Conclusions: Our results suggest that such compounds may be useful for S. aureus nasal and skin decolonization and may constitute a potent alternative for skin and nasal antisepsis before surgery. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.