Ex vivo porcine vaginal mucosal model of infection for determining effectiveness and toxicity of antiseptics

Aims To develop a semi‐high‐throughput ex vivo mucosal model for determining efficacy and toxicity of antiseptics. Methods and Results Explants (5 mm) from freshly excised, porcine vaginal mucosa were infected with methicillin‐sensitive Staphylococcus aureus (1 × 106 CFU) at the epithelial surface for 2 h. Haematoxylin and eosin staining revealed healthy uninfected tissue and only minor disruptions in tissue infected with methicillin susceptible Staph. aureus (MSSA), which remained in outer epithelial cell layers. After 2 h infection, 10 μl of chlorhexidine digluconate (CHG, 3%), povidone‐iodine (PI, 7·5%), octenidine dihydrochloride (OCT, 0·1%) or polyhexamethylene biguanide (PHMB, 0·1%) was applied. Antiseptics significantly reduced MSSA (1–4 log10 CFU/explants) after 0·25 h to 4 h. CHG, PHMB and OCT exhibited persistence at 24 h. In broth culture, CHG 0·012% and PI 0·625% achieved >6 log10 reductions at 2 h. PI‐based formulations were more efficacious than unformulated PI. PI‐based formulations exhibited no significant cytotoxicity on explants using an MTT assay. Conclusions All antiseptics tested in the mucosal MSSA infection model reduced MSSA. CHG and PI were more potent in broth culture. Significance and Impact of the Study We developed a semi‐high‐throughput mucosal model that can identify compounds or formulations with promising antimicrobial and limited cytotoxic properties.