A Phase 2 study of the novel fluoroquinolone JNJ-Q2 in community-acquired bacterial pneumonia

1 mg/L by BMD and 2 mg/L by the Etest (Table 2). When the geometric mean MIC values were compared, they varied from 0.97 to 1.28 by BMD and 0.88 to 1.23 by the Etest. The vancomycin MIC values showed fluctuation from year to year. This fluctuation was not statistically significant either by the BMD method (P ¼ 0.225) or the Etest (P¼ 0.136). Although the vancomycin MIC values fluctuated from year to year, we could not detect vancomycin MIC creep with either method. These differences between the years could be due to the large variability among the number of isolates from each year. Similar to the vanco-mycin susceptibility trend, the daptomycin MICvalues also showed fluctuation over time. This fluctuation was found to be statistically significant (P ¼ 0.005), but no MIC creep was detected between 1999 and 2009. In conclusion, although MIC fluctuation was found in our institution over time, we did not detect a decrease in vancomycin and daptomycin susceptibility among MRSA blood isolates over an 11 year period, either by BMD or the Etest. It is important to monitor the trend in vancomycin and daptomycin MICs, as changes in vancomycin MICs for S. aureus can occur over time within specific institutions.