Veterinarians often have to clip a horse’s hair to perform certain procedures, including ultrasound exams, catheter placement, and wound care. Researchers in Sweden evaluated whether microbes remain on clipper blades after “disinfection,” where they could potentially transfer to future patients in both small animal and equine practices.
Clipper Blade Contamination in Veterinary Hospitals
Clipping an animal’s hair often results in microtrauma of the skin and contamination of the clipper blade with microorganisms from the skin and hair follicles. It is possible that human skin microorganisms are also transferred to clipper blades. Because many microbes survive well in the environment, opportunistic pathogens have the potential to pass between individuals through clipper blades. One study demonstrated that bacteria grew on 51% of 60 clipper blades from 60 veterinary clinics in the U.S. Another study revealed disinfecting clipper blades inoculated with Pseudomonas, Staphylococcus aureus, and E. coli for 20 minutes with different solutions—ethanol/o-phenylphenol spray, isopropyl alcohol, and chlorhexidine—successfully eliminated the bacteria. However, the authors noted that hygienic practices between clinics and staff vary, with no specific described protocol in many countries.
Study on Clipper Blade Disinfection Protocols
The Swedish Veterinary Association has established protocols for clipper and blade disinfection: Wipe the clipper machine with an alcohol-based disinfectant that contains surfactant, then remove the blade and wipe it similarly or wash with dish disinfectant. In a recent study, researchers from Sweden and Germany examined whether these recommended disinfection routines successfully eliminate bacteria or dermatophyte contamination from clipper blades.
In the study, clipper blades sterilized by autoclave served as controls. The study included three hospitals (two small animal and one small animal and equine), but each followed a slightly different disinfection protocol. First, staff cleaned the clipper blades with a toothbrush to remove hair and debris. Then, they disinfected the blades using the following methods:
- Hospital 1: Antibacterial wipes with 45% isopropanol on the blades.
- Hospital 2 (includes equine): 45% isopropanol spray on the blades.
- Hospital 3: 40% isopropanol solution poured on the blades.
Clippers with attached blades were placed on chargers with the blades pointed upward without touching anything else. The researchers sampled 11 clipper blades from each hospital. They held each blade with new sterile gloves for swabbing and used a clean toothbrush for fungal sampling.
The results:
- Of 44 disinfected blades, 36 (88%) grew bacteria, with more than one microbe on 29 blades.
- Bacteria grew on 100% of blades from Hospital 1; 100% from Hospital 2’s equine department; and 64% from Hospital 3.
- One blade from Hospital 2’s equine department also grew Trichophyton fungal species. In a study of 900 horses between 1979-2000, dermatophytosis occurred in nearly 9% of equine cases at Cornell University. No other blades in this current study grew clinically relevant dermatophytes.
- Spore-forming Bacillus sp. contaminated many of the clippers. Not only are these bacteria difficult to eliminate with disinfection, but they are also known to create biofilms.
Ultimately, the researchers found “a high prevalence of bacterial contamination on clipper blades from all three hospitals in the study, both small animal and equine departments.”
Contamination Concerns
The authors noted that while many of the organisms recovered are not usually pathogenic, such as coagulase-negative staphylococci, it could prove problematic for immunocompromised individuals or for contamination of joints or orthopedic implants during surgery. Another major concern is the potential for antimicrobial resistance genes to transfer to more pathogenic bacterial species.
It is unknown if fungal contamination is a concern, because the researchers sampled each hospital only once. Further, fungal contaminants need sufficient keratinous material to multiply, and this study didn’t accurately determine if the prescribed disinfection procedure is sufficient to eliminate fungal concerns. More research is needed in this area.
Final Thoughts
This study was geared toward assessing disinfection routines in clinical settings. The authors suggested it’s possible that veterinarians and staff find the disinfection steps too time-consuming or complicated, or the protocol used might have been inadequate for total hygiene. It is not just the mechanics of the suggested protocol that are important, but also adherence to the protocol, which is essential to eliminate potential transfer of organisms from one animal to another. In summary, the authors reported, “Sterilization is a more reliable way to ensure that clipper blades are clean before they are used on a new patient.”
Reference
Gustafsson L., Wikstrom MC, Mueller RS, et al. Microbes on Clipper Blades after Use and Disinfection in Small Animal and Equine Practice. Vet. Sci. 2024, 11, 38; https://doi.org/10.3390/vetsci11010038
Related Reading
- Hygiene Hand Prep Update for Veterinarians and Staff
- Streptococcus equi Survivability With Cleaning and Sanitation
- Bacterial Contamination of Portable Electronic Devices
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