Polymethylmethacrylate itself has a slight, long-term bacteriostatic
effect on the growth of staphylococci, but while polymerizing the heat of
polymerization and possibly the elaboration of monomer can be bactericidal
to many pathogenic organisms. Twelve antibiotics incorporated into
polymethylmethacrylate cement retained their antibacterial activity for
long periods in dry storage, but the antibiotics leached out of
polymethylmethacrylate quite rapidly in vitro and in vivo. No antibiotic
could be found after thirty-seven days in treated cement pellets placed in
a rabbit thigh.