[Studies on the mechanism of interaction of glutaraldehyde with microorganisms (author's transl)]

The antimicrobial action of glutaraldehyde on Candida lipolytica increases with reagent concentration, pH and duration of contact. The simultaneous study of the size distribution of the particles shows an agglutination of the cells. This result is confirmed by direct observation of the cells by electron microscopy. Cell agglutination also occurs with other microorganisms (Saccharomyces carlsbergensis, Bacillus megaterium, Escherichia coli) and increases their settling rate. The formation of such intercellular bonds seems to confirm the hypothesis of a preferential action of glutaraldehyde on the outer layers of the cells. The effect of pH on the antimicrobial action of glutaraldehyde is accounted for by the fact that this reagent does not act, under neutral and alcaline conditions, as a dialdehyde but as an unsaturated polymer. This mechanism also accounts for various observations made on microorganisms-glutaraldehyde interactions.