Final answer:
The doorknob acts as a fomite for transmitting MRSA when Charlotte touches it and then scratches her leg. Handwashing is critical to prevent the spread of such infections.
Step-by-step explanation:
When Charlotte touches a doorknob after an individual with MRSA touched it and subsequently scratches a wound on her leg, potentially transmitting MRSA cells, the doorknob serves as a fomite. A fomite is any inanimate object that, when contaminated with infectious agents (like bacteria or viruses), can transfer disease to a new host.
MRSA, or methicillin-resistant Staphylococcus aureus, can survive on surfaces and be transmitted between individuals when proper hygiene is not practiced. Microbiologists stress the importance of handwashing to prevent the spread of contagious illnesses. Touching contaminated surfaces, such as doorknobs, and then touching your skin, especially if there is a wound, provides a portal of entry for pathogens like MRSA.