A nurse is providing care for a patient who has a methicillin-resistant Staphylococcus aureus (MRSA) infection, which was cultured from the urine. What is the most appropriate action for the nurse to take?

Choice A rationale:
Contact inhibition is a normal mechanism that regulates cell growth. When normal cells come into contact with each other, they stop growing. This prevents uncontrolled growth and the formation of tumors.
Benign tumor cells do not typically lose contact inhibition. They still respond to contact signals from neighboring cells and stop growing when they come into contact with each other.
However, they may grow in an uncontrolled manner due to other factors, such as mutations in genes that regulate cell growth.
Choice C rationale:
Invasion is a characteristic of malignant (cancerous) tumors, not benign tumors. Malignant tumors have the ability to invade surrounding tissues and spread to other parts of the body.
Benign tumors, on the other hand, are localized and do not invade surrounding tissues. They may grow and compress nearby tissues, but they do not spread.
Choice D rationale:
Anaplasia is a term used to describe the loss of differentiation of cells in a tumor. This means that the cells no longer resemble the normal cells from which they originated.
Anaplasia is a characteristic of malignant tumors, not benign tumors. Benign tumor cells typically retain some of the characteristics of the parent cells.

Choice A rationale:
Skin and mucous membranes are the most effective and crucial barriers to infection. They provide a continuous physical barrier that prevents pathogens from entering the body. Here's a detailed explanation of their protective mechanisms:
1. Physical Barrier:
Skin: The outermost layer of skin, the epidermis, is composed of tightly packed cells that are difficult for pathogens to penetrate. It's also covered in a layer of sebum, an oily substance that helps to repel water and microorganisms.
Mucous membranes: These moist linings cover the openings of the body, such as the nose, mouth, eyes, and digestive, respiratory, and urogenital tracts. They produce mucus, a sticky substance that traps pathogens and prevents them from entering the body. Mucus also contains enzymes and antibodies that can kill certain pathogens.
2. Chemical Barrier:
Skin and mucous membranes secrete a variety of substances that have antimicrobial properties. These include: Sebum: Contains fatty acids that can kill bacteria and fungi.
Sweat: Contains salt and lysozyme, an enzyme that can break down bacterial cell walls. Saliva: Contains enzymes that can break down food and kill bacteria.
Gastric acid: The highly acidic environment of the stomach kills most pathogens that are ingested.
3. Immune Barrier:
Skin and mucous membranes are home to a diverse community of microbes, known as the microbiome. These microbes play an important role in protecting against infection by competing with pathogens for resources and space.
Mucous membranes contain specialized immune cells, such as M cells and dendritic cells, that can recognize pathogens and initiate an immune response.
In contrast, the other choices are less effective barriers to infection:
Choice B: Gastrointestinal secretions, such as gastric acid, do play a role in preventing infection, but they are not as effective as skin and mucous membranes. Pathogens can still enter the body through the digestive tract, even in the presence of gastric acid.
Choice C: Colonization by host bacteria can actually help to protect against infection by competing with pathogens. However, it is not a primary barrier to infection.
Choice D: Inflammatory processes are a response to infection, not a barrier to it. They occur after pathogens have already entered the body.