Methicillin-resistant Staphylococcus aureus (MRSA)
infections are prevalent in
burn wards, and are especially serious in S. aureus
bacteremia (SAB) patients.
Glycopeptides and
daptomycin are effective against MRSA
infections, but MIC creeps can reduce their efficacy. Our object was to perform a molecular epidemiological investigation of S. aureus isolates in our burn center and to evaluate MICs for antimicrobials against SAB-associated MRSA isolates. A total of 259 S. aureus isolates, obtained from August 2011 to July 2016, were used in this study. Multiple molecular typing was used for molecular epidemiological analysis. E-tests were used to determine MICs of
vancomycin,
teicoplanin, and
daptomycin for SAB-associated MRSA isolates. MIC values were stratified by collection date or source and compared. Spearman's test was used to analyze MICs correlations amongst tested antimicrobials. ST239-MRSA-III-t030-agrI clone was found to be dominant in both SAB and non-SAB patients, and significantly more in SAB patients (P < 0.0001). SAB-MRSA isolates exhibited decreased MICs for
vancomycin,
teicoplanin, and
daptomycin during the 5-year period. Compared to those isolated from
catheters or
wounds, SAB-MRSA isolates from the bloodstream were less susceptible to
vancomycin and
daptomycin, but more susceptible to
teicoplanin. MICs Correlation was found only between
vancomycin and
daptomycin in MRSA isolates from the bloodstream (rho = 0.250, P = 0.024). In conclusion, our results suggest that MRSA
infections are still serious problems in burn centers. In contrast to most other studies, we observed increased susceptibility to
glycopeptides and
daptomycin against SAB-associated MRSA in our center from 2011 to 2016, suggesting the use of
glycopeptides does not lead to MIC creeps. Isolates from different sites of the body may exhibit different levels of susceptibility and change trend over time for different antimicrobials, antimicrobials selection for MRSA
infections should be considered comprehensively.