Influence of chemotherapeutic agents on the antibacterial activity of normal and leukemic sera.

Abstract

The influence of various chemotherapeutic agents on the antibacterial activity of normal and leukemic sera was tested by bacteriolytic and bactericidal assays with use of 2 rough strains of Escherichia coli, one sensitive to the antlbacterlal activity of human serum and another resistant to such action. With a “low” dose of drugs, daunorublcine, mechlorethamine, and methotrexate slightly inhibited early stages of bacteriolytic activity of normal human serum against E. coli Lilly. With a "high" dose of drugs, mechlorethamine, daunorubicine, and cytarabine definitely enhanced early stages of bacteriolytic activity. Enhancement of bactericidal activity of normal human serum against E. coli Lilly was achieved by admixture with 1,3-bis(2-chloroethyl)-l-nitrosourea (SCN.U, carmustine) fluorouracil, methotrexate, vincrisUne, cytarabine, and prednisone. There was no enhancement of antibacterial activity by any drug against E. coli resistant to the action of normal human serum. Preincubation of E. coli Lilly with various drugs indicated that their enhancing activity was not expressed when the bacterial envelope was intact. Sera of patients receiving cyclophosphamid e intravenously did not differ in antibacterial activity from the samples drawn before the injection. Apparently certain chemotherapeutic agents influence antibacterial activity of the serum in vitro against some microorganisms. This fact should be considered when defense mechanismsof patients with leukemia or cancer are investigated.