ROLE OF CHEMOTHERAPEUTIC ANTAGONISM IN OPPORTUNISTIC INFECTIONS

The most widely-known anti-tumour drugs often induce marked immunosupp ression which can give rise to one or more sepses. Anti-infection meas ures immediately applied can sometimes prove largely ineffective or ev en useless, the patient dying not as a result of the spread of the tum our but as a direct consequence of opportunistic infection. We postula te that antagonism between anti-tumour and antimicrobial drugs may als o play an important part in this. By way of illustration of this hypot hesis, we have studied the action of a number of known inhibitors of p eptidoglycan synthesis and of DNA-gyrases on certain strains of Gram-p ositive and Gram-negative microorganisms cultured in medium containing various concentrations of some of the best-known anti-tumour antimeta bolites. The experimental data show that antimicrobial and anti-tumour drugs can sometimes induce synergic or indifferent chemotherapeutic i nteractions with many bacteria, while in others the effect is antagoni stic. In practice, the action of the drugs could lead to bacterial sel ectivity, which, in conjunction with immunosuppression and the presenc e of resistant strains, could favour the evolution of opportunistic in fection.