Keep Otoscope Cones Clean

During otoscopic examinations, the cone comes into contact with ear exudate and the walls of the ear canal. Because bacterial and yeast contamination is expected, it is routine to clean and disinfect otoscopic cones. In this study, cleaning and disinfection procedures were reviewed and recorded in 50 small animal practices. To determine whether the cones were contaminated, the investigator blindly selected 2 4-mm cones to swab at each practice. Seventy-one of the cones sampled were sterile, 15 were contaminated with nonpathogenic bacteria, and 13 were contaminated with pathogenic bacteria (Flavobacterium, Pseudomonas, Staphylococcus, Corynebacterium, Bacillus, Enterococcus, and Malassezia). No significant difference or clinical trend was found between contamination and storage of the cones (dry vs wet) or cleaning methods. Not unexpectedly, a greater number of appointments seen at a hospital correlated with higher levels of contamination. In addition, the longer the cones were in solution, the more likely they were to become contaminated. Because of the large number of cleaning solutions, a single most effective solution could not be identified. However, Cetylcide-G (cetylite.com), Benz-all (xttrium.com), and 2% chlorhexidine gluconate were the 3 most commonly used products. Of these, cones disinfected with Cetylcide-G had no growth when the solution was used as directed.

Commentary: This small study offers several important take-home points. First, many of the hospitals had no standard method of disinfection. Explicit protocols are needed to ensure that medical equipment is adequately cleaned and disinfected. Second, in 8% of the hospitals, contaminated cones were stored near other medical equipment, which can result in passive contamination of equipment and put patients at risk for infection. Innovative Veterinary Products (innovativeveterinaryproducts.com) makes inexpensive disposable ear cones from recyclable material. My colleagues and I have begun using these in our clinic after reading this article.

Evaluation of otoscope cone disinfection techniques and contamination level in small animal private practice. Kirby AL, Rosenkrantz WS, Ghubash RM, et al. VET DERMATOL 21:175-183, 2010.