Mupirocin resistance: clinical implications and potential alternatives for the eradication of MRSA.

Mupirocin 2% ointment is used either alone or with skin antiseptics as part of a comprehensive MRSA decolonization strategy. Increased mupirocin use predisposes to mupirocin resistance, which is significantly associated with persistent MRSA carriage. Mupirocin resistance as high as 81% has been reported. There is a strong association between previous mupirocin exposure and both low-level and high-level mupirocin resistance. High-level mupirocin resistance (mupA carriage) is also linked to MDR. Among MRSA isolates, the presence of the qacA and/or qacB gene, encoding resistance to chlorhexidine, ranges from 65% to 91%, which, along with mupirocin resistance, is associated with failed decolonization. This is of significant concern for patient care and infection prevention and control strategies as both these agents are used concurrently for decolonization. Increasing bacterial resistance necessitates the discovery or development of new antimicrobial therapies. These include, for example, polyhexanide, lysostaphin, ethanol, omiganan pentahydrochloride, tea tree oil, probiotics, bacteriophages and honey. However, few of these have been evaluated fully or extensively tested in clinical trials and this is required to in part address the implications of mupirocin resistance.