Alterations of penicillin-binding proteins in pneumococci with stepwise increase in β-lactam resistance

Infection caused by Streptococcus pneumoniae has become increasingly complicated and costly to treat due to the increase in β-lactam resistance. A total of 80 pneumococcal isolates with stepwise increase in penicillin and ceftriaxone resistance were analyzed for the sequential changes in their penicillin-binding proteins (PBPs) 1a, 2b, and 2x. The result provides an insight into the evolution of PBPs associated with β-lactam resistance in a natural population of S. pneumoniae.