Assay performance with ciprofloxacin.

<p>Relative growth values for 35 <i>S</i>. <i>aureus</i> strains derived from the MBT-ASTRA assay performed with ciprofloxacin are shown. A relative growth cutoff of 0.5 was utilized to classify resistance, indicated by the horizontal line. Strains are arranged from left to right in order of increasing MIC, with exact values given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0183899#pone.0183899.t001" target="_blank">Table 1</a>. Data points colored red indicate major or very major errors. For each strain, 4–6 independent replicates were obtained on different days.