[Bacteriological study on the chemotherapeutic combination sulfametrole-trimethoprim/comparison with co-trimoxazole...

The synergism of the compounds Nd-(4-methoxy-1,2,5-thiadiazol-3-yl)-sulfanilamide (sulfametrole; SOL) and 2,4-diamino-5-(3',4',5'-trimethoxy-benzyl)-pyrimidine (trimethoprim; TMP) contained in the preparation Lidaprim was proved in vitro in the agar dilution test, the disc agar diffusion method as well as a crossover test against various grampositive and gramnegative bacteria. Sulfametrole enhanced the activity of trimethoprim or its activity was intensified by trimethoprim, respectively. The increase in efficiency depends on the primary sensitivity or resistance of the bacteria against trimethoprim and/or the sulfonamide. The combination of trimethoprim + sulfametrole (1 + 20) had the same antibacterial activity as the combination co-trimoxazole = trimethoprim + Nd-(5-methyl-3-isoxazolyl)-sulfanilamide (sulfamethoxazole; SMZ). The bactericidal efficiency was shown against a strain of E. coli. Using the combination experimental development of resistance against various bacteria could not be obtained (10 times repeated contact with subbacteriostatic concentrations). Chemotherapeutical experiments in the mouse have confirmed the enhancement indicated in vitro of the combination trimethoprim-sulfonamide, irrespective of the sulfonamides chosen. Determinations of the intestinal flora before, during and after oral administration of 2 X 2 tablets SOL-TMP (Lidaprim) over a period of 10 days showed that the absolute number of bacteria in samples of faeces had not been reduced. Enterobacteria and anaerobic lactobacilli (L. bifidus), which could not be identified during the period of administration, reappeared after the end of therapy.