FIG 2.

Schematic representation of transformation steps. The genes of PBP2x, PBP1a, MurM, and CiaH present in penicillin-resistant strain Hu17 (top right) were introduced individually or in various combinations into sensitive nonencapsulated laboratory strain S. pneumoniae R6 or into clinical isolate Hu15, as indicated by the colors. The direction of gene transfer is indicated by arrows. Gray circles represent recipient strains R6 and Hu15 and donor strain Hu17. Transformants containing all four genes are identified at the bottom and named according to the order of the transformation steps.