Community-Associated Staphylococcus aureus ... - SWACM

Concordance Among Index CaseInfecting and Colonizing StrainsIndex Cases163Concordance Among Index CaseInfecting and Household ContactColonizing StrainsIndex Cases163Colonizingstrains =Infectingstrains: 109(67%)Colonizingstrains ≠Infectingstrains: 54(33%)HHcolonizingstrain =Infectingstrain: 75(46%)HHcolonizingstrain ≠Infectingstrain: 57(35%)No HHcontactColonization31 (19%)Rodriguez M, et al. 49 th Annual Meeting of the Infectious Diseases Society of America, 2011Rodriguez M, et al. 49 th Annual Meeting of the Infectious Diseases Society of America, 2011Challenges toDecolonizationMupirocin Resistance• Low-level resistance– MIC 8-128 µg/mL– Alteration in the isoleucyl-tRNA synthetase geneileS• High-level mupirocin resistance– MIC ≥256 µg/mL– Conferred by the plasmid-encoded mupA gene• Encodes novel isoleucyl-tRNA synthetase• Plasmids carrying the mupA gene may carry resistancegenes for other systemic antibioticsPatel JB, et al. Clin Infect Dis 2009; 49:935-41Cadilla A, et al. J Clin Microbiol 2011; 49:95-100Clinical and Laboratory Standards InstituteMupirocin Resistance• Widespread use of mupirocin in thecommunity has been associated withincreasing resistance 1• Mupirocin resistance may be related todecolonization failure 2• Up to 12% of S. aureus SSTI are caused bymupirocin resistant strains 3(1) Upton A, et al. J Antimicrob Chemother 2003; 51:613-7(2) Lee AS, et al. Clin Infect Dis 2011; 52:1422-30(3) McNeil JC, et al. Antimicrob Agents Chemother 2011; 55:2431-3Mupirocin Resistance and EradicationSuccessBaseline Mup-RPatients with S. aureus108923 Mup-R 1066 Mup-SPrescribed Mupirocin408Baseline Mup-SColonized atColonized atOne MonthOne Month4/4 (100%) 144/324 (44%) p=0.041Fritz SA, et al. 49 th Annual Meeting of the Infectious Diseases Society of America, 201111