FIG 6.

Spheroplast formation and recovery in human serum. (A and B) The indicated isolates were grown overnight in serum growth medium (SGM), diluted 1:10 (final volume, 500 μl) into fresh SGM, and incubated in the presence (A) or absence (B) of 10 μg/ml meropenem. Cells were plated (CFU per milliliter) at the indicated time points. (C) After 6 h of incubation, purified NDM-1 carbapenemase was added to remove meropenem, followed by time-lapse microscopy on agarose pads containing 40% (vol/vol) human serum. All values represent means of results from three biological replicates; error bars represent standard errors of the means. The red circle indicates the initial growth steps of a recovering spheroplast within cell debris.