Effect of peritoneal dialysis solution on the antimicrobial activity of cephalosporins

We studied the effect of peritoneal dialysis solution (PDS) on the antibacterial activity of seven cephalosporins, gentamicin, tobramycin and amikacin. The six bacterial species employed in the study survived in a wide range of concentrations of PDS, however, Staphylococcus aureus did not survive beyond 24 h in PDS. There were no physical incompatibilities between any of the antibiotics and PDS. None of the cephalosporins was bactericidal in PDS, whereas, the bactericidal concentrations of the aminoglycosides in PDS approximated those of aminoglycosides in broth. We conclude from these in vitro data that cephalosporins may not be ideal agents for intraperitoneal therapy when they are administered in PDS.