Studies on the Combined Use of Various Drugs against Antibiotic-Resistant Strains of Dysentery Bacilli

Abstract

Investigations were carried out on the combined use of various drugs against antibiotic-resistant strains of dysentery bacilli.
Combined use of 2 drugs were studied with 49 combinations revealing the following 6 combinations to demonstrate an increase of antibiotic activity against drug-resistant strains: TC-KM, TC-PM, TC-Pol-B, TC-B.E, TC-FM and CP-Pol-B. Synergistic effects were noticed only between FM and Vic. On the other hand, antagonistic effects were noticed between KM and Co.S and in other 17 combinations, whereas the other 25 combinations demonstrated neither synergistic nor antagonistic effects. These results might suggest no great expectation on an increase of antibiotic activity by combined use.
Prevention of the acquirement of antibiotic resistance was investigated with 3 combinations of 2 drugs. FM-Vic and KM-Co.S demonstrated an inhibition of increase of resistance against Vic and KM, whereas KM-TC raised more rapidly drug-resistance as compared with alone use.