Final answer:
Regular hand hygiene is the first line of defense in preventing the spread of microorganisms, especially important for health-care workers to reduce pathogen transmission.
Step-by-step explanation:
The first line of defense in preventing the spread of microorganisms is performing regular hand hygiene. This action is crucial as it effectively reduces the transmission of pathogens that health-care workers may come into contact with through a variety of surfaces and patient interactions. Handwashing is especially significant, as it should occur between every patient contact, upon glove removal, and after exposure to bodily fluids or potentially infectious materials.
In addition, hand hygiene is an important step before and after medical procedures to maintain aseptic technique and prevent microbial contamination. Keeping hands clean is the most effective measure to prevent the spread of contagious illnesses, as pathogens are ubiquitous and can transfer from surfaces to individuals easily.