A comparative study of the effect of oral treatment with augmentin, amoxycillin and bacampicillin on the faecal flora in mice.

Oral treatment of groups of four mice with different daily dosages of three related antibiotics, amoxycillin, augmentin and bacampicillin, has indicated the influence of the amount of the dose that reaches the intestine in a biologically active form. Augmentin (amoxycillin plus clavulanic acid to protect it against enzymatic hydrolysis) appeared to have a suppressive effect on the indigenous colonization-resistance-associated microflora. Dose-effect curves of amoxycillin alone, showed the same shape but at a lower level. Bacampicillin treatment practically did not have an effect on the faecal flora. Only at doses of bacampicillin of well above 1.5 mg per day, an indication was seen of CR-flora disturbance. At a dose level of 2 mg and more per day, a low concentration of beta-aspartylglycine was found in the faeces. A normal undisturbed intestinal flora normally produces in mice sufficient enzyme to degrade completely this dipeptide released by the host organism into the intestinal tract.