Which action by the practitioner is most effective in preventing the spread of germs?

Washing hands is the most effective action in preventing the spread of germs because it physically removes dirt, organic matter, and microorganisms from the skin's surface. Handwashing with soap and water is crucial, especially before and after performing any salon services, as it significantly reduces the presence of pathogens that can lead to infection or illness.

While using gloves is an important practice in a nail technician's routine, it alone does not eliminate the germs from the hands, and gloves can become contaminated during use. Disinfecting tools is essential for ensuring that surfaces and implements remain clean and free of harmful bacteria, but it does not directly address germs that may be on the practitioner's hands before they begin a procedure. Using hand sanitizer is a good supplemental measure when soap and water are not available; however, it is less effective than thorough handwashing, especially if hands are visibly soiled.

Overall, handwashing is the foundational practice in infection control and hygiene, making it the most effective option in preventing the spread of germs among clients and in the salon environment.