Shown is a repeat of an earlier slide to allow us to make another point. We isolated colonies from various points along these curves, which were generated for moxifloxacin and levofloxacin with S. pneumoniae. We then determined the nucleotide sequences of the QRDR (quinolone-resistance-determining regions) for the gyrA, gyrB, parC, and parE genes. The results, shown in the next slide, illustrate differences between the two target genes.