Interaction between antibiotics and antineoplastic drugs on antibacterial activity in-vitro - estramustine phosphate...

The antibacterial and interactive effects of doxorubicin, cisplatin, cytarabine, vincristine, carmustine, mitoxantrone, methotrexate, bleomycin, 5-fluorouracil, epirubicin, DTIC, mitomycin, etoposide and estramustine phosphate on the antibacterial activity of penicillin G, piperacillin, ceftazidime, imipenem, trimethoprim, amikacin, tetracyclin, oxacillin, metronidazole, 5-FC, and amphotericin B were studied on 57 bacterial strains. The bacterial species investigated were Escherischia coli, Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Streptococcus pneumoniae, and Bacteroides fragilis. The antineoplastic drugs were diluted in Muller-Hinton agar on which the bacteria were propagated. For the susceptibility tests standard antibiotic paper discs were used and results were confirmed with the PDM epsilometer test. Seven of the fourteen cytostatic agents displayed an intrinsic antibacterial effect. A most striking interactive effect was seen in the situation where estramustine phosphate caused a marked increased sensitivity of pneumococci to amikacin, a drug to which they are regularly completely resistant.