Katrin Steinhauer, Peter Goroncy-Bermes
The first barrier for cationic molecules attacking gram-positive microorganisms is the cell wall and its amount of net negative charge. Modification of the cell wall by esterification of teichoic acids provides a very effective mechanism to resist such attacks up to a certain degree.
Our data demonstrates that also for the cationic octenidine dihydrochloride association with the cell wall of gram-positive bacteria is dependent on the negative net charge of the cell wall. However, even though this provides some protection our data proves, that the penetration of the biocide through the peptidoglycan layers cannot be prevented at increasing concentrations as shown by LIVE/DEAD staining, thus resulting in a lethal damage of the bacterial cells.
In addition it could be demonstrated, that interaction of octenidine dihydrochloride with the bacterial cell wall results in a significantly enhanced phagocytosis by neutrophils in human blood.