OBJECTIVE: To test the efficacy of a previously described neutralising agent to counteract any antimicrobial activity of 0.2% of chlorhexidine (CHX) mouthrinse on the salivary flora, which is only exhibited after sampling of surviving bacteria, resulting in false positive efficacy data. METHODS: Unstimulated salivary samples were collected of 20 volunteers under basal conditions and at 30s and 1h after of a single mouthrinse of 0.2% CHX. Each salivary sample was divided into 2 equal aliquots; one was mixed with neutralising agent (3% Tween 80, 0.3% lecithin and 0.1% cysteine) and the other with a control solution. The colony forming units (cfu/mL) were determined and expressed as logarithms (log(10)cfu/mL). RESULTS: At baseline, the total bacterial concentrations were similar, independently of the addition of neutralising solution or control solution (8.419+/-0.346log(10)cfu/mL and 8.462+/-0.474log(10)cfu/mL, respectively, p=0.440). At 30s performing the CHX mouthrinse, the bacterial load reduction was statistically significant between both sampling methods (1.917+/-1.275log(10)cfu/mL, p<0.001). One hour after performing the CHX mouthrinse, the bacterial load reduction was statistically significant between both sampling methods (0.537+/-0.706log(10)cfu/mL, p=0.003). CONCLUSIONS: Neutralising agent was not toxic to the bacterial salivary flora and effectively deactivated the "residual antimicrobial activity" of the 0.2% CHX (after exposure and during processing of samples). We propose the use of this neutralising agent when evaluating the antibacterial activity of CHX mouthrinses.
OBJECTIVE: To test the efficacy of a previously described neutralising agent to counteract any antimicrobial activity of 0.2% of chlorhexidine (CHX) mouthrinse on the salivary flora, which is only exhibited after sampling of surviving bacteria, resulting in false positive efficacy data. METHODS: Unstimulated salivary samples were collected of 20 volunteers under basal conditions and at 30s and 1h after of a single mouthrinse of 0.2% CHX. Each salivary sample was divided into 2 equal aliquots; one was mixed with neutralising agent (3% Tween 80, 0.3% lecithin and 0.1% cysteine) and the other with a control solution. The colony forming units (cfu/mL) were determined and expressed as logarithms (log(10)cfu/mL). RESULTS: At baseline, the total bacterial concentrations were similar, independently of the addition of neutralising solution or control solution (8.419+/-0.346log(10)cfu/mL and 8.462+/-0.474log(10)cfu/mL, respectively, p=0.440). At 30s performing the CHX mouthrinse, the bacterial load reduction was statistically significant between both sampling methods (1.917+/-1.275log(10)cfu/mL, p<0.001). One hour after performing the CHX mouthrinse, the bacterial load reduction was statistically significant between both sampling methods (0.537+/-0.706log(10)cfu/mL, p=0.003). CONCLUSIONS: Neutralising agent was not toxic to the bacterial salivary flora and effectively deactivated the "residual antimicrobial activity" of the 0.2% CHX (after exposure and during processing of samples). We propose the use of this neutralising agent when evaluating the antibacterial activity of CHX mouthrinses.
Authors: Thaer Abouassi; Christian Hannig; Katja Mahncke; Lamprini Karygianni; Martin Wolkewitz; Elmar Hellwig; Ali Al-Ahmad Journal: BMC Res Notes Date: 2014-10-10