Antimicrobial activity of cytotoxic drugs may influence isolation of bacteria and fungi from blood cultures

Abstract

The potential antimicrobial activity of cyclophosphamide, vincristine, and adriamycin against Gram positive and negative bacteria and Candida albicans was examined. The time taken for different microbial inocula to turn a simulated blood culture positive in the presence of different concentrations of these drugs was measured. Doxorubicin retarded the growth of Staphylococcus aureus, Staphylococcus epidermnidis, and Streptococcus sanguis in a concentration dependent manner. Cyclophosphamide and vincristine showed mimal antimicrobial activity. Escherichia coli and Pseudomonas aeruginosa were unaffected by any of the drugs. An inoculum dependent effect was seen with some combinations of microbial inocula and cytotoxic drug concentrations.