This information is provided by:
Grant Stiver MD, FRCPC
Editorial Board Member for the CAN-R Website
Fusidic acid (FA) (Fucidin®) combined with another antimicrobial such as rifampin,
has been observed to be effective in treating methicillin-resistant Staphylococcus aureus (MRSA)
infections, particularly skin and soft tissue infections.1 However resistance develops readily with
FA monotherapy, and this may have been the reason that the drug was never licensed in the United States.
Although current use of FA for treatment of FA-susceptible MRSA invasive infection includes a second agent
such as rifampin to mitigate the emergence of resistance, this has not been the case for topical FA,
which is usually used alone. The use of topical FA has been shown to correlate with increased FA
resistance in S. aureus. In Norway, an FA-resistant clone of S. aureus was associated
with summer outbreaks of bullous impetigo, when topical FA alone was frequently used.2 Similarly, rates of
FA resistance in S. aureus rose from 6% to 11.5% from 1998 to 20013 in Bristol England and the
number of prescriptions for topical FA in the United Kingdom doubled during that time. FA resistance
rates for S. aureus in some countries approach 67%. Caution has been raised regarding increasing
rates of resistance to mupirocin. Mupirocin resistance in MRSA was also associated with a five-fold higher
rate of FA resistance (21% versus 4%).5 A strong case has been made for restriction or abolition of
topical FA, to prevent the loss of this useful agent in combating both methicillin-resistant and
susceptible S. aureus.6 Fusidic acid resistance and associated factors need to be carefully
monitored by cross-Canada surveillance networks.
- Whitby M. Fusidic acid in the treatment of methicillin-resistant Staphylococcus aureus. Internat J Antimicrob Agents 1999;12 (Suppl 2):S67-71.
- Tveten Y et al. A fusidic acid-resistant clone of Staphylococcus aureus associated
with impetigo bullosa is spreading in Norway. J Antimicrob Chemother 2002;50: 873-6.
- Brown EM, Wise R. Fusidic acid cream for impetigo. BMJ 2002;324:1394.
- Nickerson E et al. Staphylococcus aureus bacteremia in a tropical setting: patient outcome and impact of antibiotic resistance. PloS One 2009;4:1-7.
- Simor AE et al. Mupirocin-resistant methicillin-resistant Staphylococcus aureus (MRSA) in Canadian hospitals. Antimicrob Agents Chemother 2007;51:3880-6.
- Howden B, Grayson ML. Dumb and dumber – the potential waste of a useful antistaphylococcal agent: emerging fusidic acid resistance in Staphylococcus aureus. Clin Infect Dis 2006;42:394-400.
