COMPARATIVE EFFECTS OF CEFADROXIL AND PHENOXYMETHYLPENICILLIN ON THE NORMAL OROPHARYNGEAL AND INTESTINAL MICROFLORA

The ecological effects on the commensal microflora in saliva and stool samples were studied during administration of two commonly used antib iotics: cefadroxil 500 mg b.i.d. for 10 days and phenoxymethylpenicill in Ig b.i.d. for 10 days. Twenty healthy volunteers participated in th e study In the oropharyngeal microflora the aerobic microflora was sig nificantly suppressed during administration of cefadroxil while no sig nificant changes were noticed in the anaerobic microflora. Administrat ion of phenoxymethylpenicillin caused a strong decrease in the number viridans streptococci and an overgrowth of Neisseria cocci. The total numbers of anaerobic oropharyngeal microorganisms were suppressed duri ng phenoxymethylpenicillin administration. In the intestinal microflor a the variation in numbers of aerobic and anaerobic microorganisms was minor in both groups. The microflora became normalised 2 weeks after withdrawal of the drugs. It was concluded that peroral administration of cefadroxil to healthy volunteers resulted in minor ecological distu rbances in the oropharyngeal and intestinal microflora, which were in the same range as for phenoxymethylpenicillin.