Comparative study of the antimicrobial activity of bis(Nalpha-caproyl-L-arginine)-1,3-propanediamine dihydrochloride and chlorhexidine dihydrochloride against Staphylococcus aureus and Escherichia coli.
OBJECTIVE
The aim of this study is to gain insight into the mechanism of the antimicrobial action of a novel arginine-based surfactant, bis(N(alpha)-caproyl-L-arginine)-1,3-propanediamine dihydrochloride [C(3)(CA)(2)].


METHODS
To this end, we compared its effects against Staphylococcus aureus and Escherichia coli with those caused by the commercial and widely known antiseptic, chlorhexidine dihydrochloride (CHX).


RESULTS
Both disrupted the cell membrane of the target bacteria to cause potassium leakage and morphological damage. The effect of C(3)(CA)(2) on E. coli was concentration dependent, causing loss of membrane potential and membrane integrity leading to cell death, whereas CHX did not have these effects on E. coli. The effect of C(3)(CA)(2) on S. aureus was the formation of mesomes and cytoplasmic clear zones, but the loss of membrane potential and membrane integrity was slightly lower than that with CHX.


CONCLUSIONS
We propose that C(3)(CA)(2) acts preferentially against Gram-negative bacteria through strong initial binding to the surface lipopolysaccharides and subsequently partitioning into the cell membrane to cause membrane damage, followed by cell death.
Institute for Chemistry and Environmental Research, Barcelona, Spain.
José A
JA
Castillo
Pere
P
Clapés
M Rosa
MR
Infante
Jaume
J
Comas
Angeles
A
Manresa
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D001120:Arginine / Q000737:chemistry; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D002710:Chlorhexidine / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D005434:Flow Cytometry; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D011188:Potassium / Q000502:physiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D013501:Surface-Active Agents; D001120:Arginine; D002710:Chlorhexidine; D011188:Potassium