FIG. 1.

Prominent amino acid substitutions in the PBD of PBP 1A from penicillin-resistant pneumococcal isolates compared to the sequence of susceptible strain R6 (two or more consecutive substitutions are boxed). The positions of the three conserved amino acid sequence motifs (STMK, SRN, and KTG) are indicated. (A) Amino acid sequence data for strain R6. (B) Amino acid substitutions for isolates for which MICs were from 0.25 to 1 μg/ml. (C) Amino acid substitutions for isolates for which MICs were ≥2 μg/ml. The data are numbered according to the published sequence of Martin and coworkers (14).