Octenidine Dihydrochloride

Abstract

Octenidine dihydrochloride (OCT), mostly in combination with 2% phenoxyethanol, is bactericidal (1 min) and yeasticidal (30 s) at 0.1%. The mycobactericidal activity is unknown. Epidemiological cut-off values to determine acquired resistance have not been proposed yet. Elevated MIC values suggestive of OCT tolerance have been reported among few species including S. salivarius (≤800 mg/l), P. aeruginosa (≤128 mg/l) and S. mutans (≤120 mg/l). Specific resistance mechanisms have not been described yet. Cross-tolerance to chlorhexidine and selected antibiotics can occur in P. aeruginosa. Low-level exposure leads to no or a weak MIC change in S. aureus and a strong and stable MIC change in P. aeruginosa resulting in MIC values as high as 128 mg/l. Bacterial biofilm formation is rather inhibited than enhanced by high concentrations of OCT (0.31–3%). OCT (0.1%) in combination with 2% phenoxyethanol can mostly remove single-species biofilm in 30 min, but the effect on mixed-species biofilm removal is poor.