ERRATUM
Volume 5, no. 6, doi:10.1128/mBio.02141-14, 2014. The x axis of the right panel of Fig. 3C was mislabeled. Panel C should appear as shown below.
Volume 5, no. 6, doi:10.1128/mBio.02141-14, 2014. The x axis of the right panel of Fig. 3C was mislabeled. Panel C should appear as shown below.