The Effect of Antibiotics on Experimental Malaria (Plasmodium Cathemerium and Plasmodium Berghei)

Abstract

Summary and Conclusions Certain antibiotics derived from various types of Streptomyces possess definite antimalarial properties. Against Plasmodium cathemerium in the canary, aureomycin and terramycin have marked prophylactic effect and even afford complete protection in some instances when administered for 10 days or longer. Aureomycin has a suppressive effect equal to that of quinine, and terramycin a relatively poor suppressive effect against the blood parasites. Chloramphenicol has a meager prophylactic and suppressive effect only in maximum tolerated doses. None of these drugs proved to be curative, either alone or in combination with quinine. Dihydrostreptomycin, neomycin, rimocidin, thiolutin, and two Brucella-active lyophilized broths were totally ineffective. The same three antibiotics, aureomycin, terramycin, and chloramphenicol, show a suppressive effect in P. berghei infections in the white mouse. Aureomycin is again nearly equivalent to quinine, while terramycin and chloramphenicol both have rather low quinine equivalents of 0.16 and 0.17 respectively. Neomycin had no suppressive effect on P. berghei infections. The marked prophylactic effect of certain of these antibiotics, confirming previous reports of such activity by others indicates further search for more effective preparations in this group. To our knowledge, causal prophylaxis is demonstrated by only two other compounds against P. cathemerium infections—metachloridine (Wiselogle, 1946) and Endochin (unpublished observations). As this type of antimalarial activity may be interpreted as bearing chiefly on the exo-erythrocytic forms of the parasite, there is a possibility that among the antibiotics or a combination of one of them with another antimalarial will be found a less toxic curative agent for vivax malaria.