In Vitro Activity of Octenidine Dihydrochloride-Containing Lozenges against Biofilm-Forming Pathogens of Oral Cavity and Throat

Abstract

The disruption of the balance in the composition of oral and throat microbiota due to overgrowth of infectious biofilms may lead not only to severe infections, but also to serious, systemic complications resulting in a permanent loss of health or even in the death of the patient. Therefore, a number of hygienic measures are applied to counter-act such a threat, including the provision of locally active antiseptic agents. In this work, the antimicrobial activity of a well-established drug, octenidine dihydrochloride, in a new formulation of lozenges toward the biofilms formed in vitro by Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Pseudomonas aeruginosa and Aggregatibacter actinomycetemcomitans was assessed. The metabolic activity and quantitative culturing were performed and also scanning electron and confocal microscopies with regard to these biofilms exposed to the activity of octenidine in lozenges vs. a comparator (octenidine dihydrochloride dissolved in liquid). Biofilms were cultured in different experimental settings, including one in which hydroxyapatite served as the biofilm growth surface and using artificial saliva as the biofilm milieu. The obtained results indicated that the tested formulation of octenidine-containing lozenges displayed a high efficacy towards the analyzed biofilms, regardless of the in vitro setting applied. The current work is of a strictly in vitro nature, and the analyses were performed on reference microbial strains and not on the spectrum of clinical strains. Nevertheless, considering the fact that the time of exposition of biofilm to the octenidine released from the lozenge is significantly longer than the contact time of an antiseptic dissolved in liquid also tested in this study, it can be assumed that stable carriers of octenidine may find its broad application in the maintenance of oral and throat hygiene and the eradication of biofilm-based infections.