Evaluation of the Antimicrobial Activity of a 3% Chlorhexidine/Ophytrium Mousse and Shampoo in 18 Healthy Dogs

Abstract

ABSTRACT Background Topical antimicrobial therapy is vital for managing pyoderma yet poor compliance can affect treatment outcomes. Hypothesis/Objective To evaluate the antimicrobial activity of a 3% chlorhexidine/ophytrium shampoo at different contact times and the residual activity of a 3% chlorhexidine/ophytrium mousse against meticillin‐susceptible and ‐resistant Staphylococcus pseudintermedius (MSSP and MRSP), Escherichia coli (EC), ESBL‐producing E. coli (ESBL), Pseudomonas aeruginosa (PA), and Malassezia pachydermatis (MP) in vitro. Animals 18 privately owned dogs. Materials and Methods Dogs were treated once with the shampoo for 3, 5 and 10 min, with hair samples taken after rinsing. The mousse was applied once. Hair samples were collected at 30 min (Day [D]0) and at D2, D4, D7 and D14 post‐treatment. Hair bundles were plated on Mueller–Hinton (MH) agar plates pre‐inoculated with MSSP, MRSP, EC, ESBL and PA, and on supplemented MH plates pre‐inoculated with MP. Zones of inhibition (ZIs) were measured after 24 h (bacteria) and 48 h (MP) incubation. Results Shampoo—there were no significant differences in antimicrobial activity between the contact times for any of the isolates. Mousse—for all the isolates, there was significant growth inhibition compared to the negative controls on D0, D2 and D4. Conclusions and Clinical Relevance Hairs exposed to the shampoo and mousse inhibited growth of all the isolates in vitro. A 3 min contact time was noninferior to 10 min for the shampoo. The mousse showed residual activity for ≥ 4 days for MSSP, MRSP, EC, PA and MP.