A patient about to undergo surgery is expressing anxiety. Which nurse’s response is most likely to encourage further conversation with the patient?

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.

Choice A rationale:
Plague is a highly contagious and often fatal disease caused by the bacterium Yersinia pestis. It is transmitted to humans through the bites of infected fleas or by direct contact with infected animals or their tissues.
Plague can cause severe illness and death, even with prompt treatment. The mortality rate for untreated plague is 50-60%. Therefore, it is incorrect to state that plague produces a mild illness and generally has a low mortality rate.
Choice C rationale:
Smallpox is a highly contagious and deadly disease caused by the variola virus. It was eradicated in 1980, but there is still a risk that it could be used as a bioweapon.
Most people under the age of 40 have not been vaccinated against smallpox and therefore have no immunity to the disease. Therefore, it is incorrect to state that the majority of Americans have adequate innate immunity to smallpox.
Choice D rationale:
Safer food preparation practices have helped to decrease the incidence of foodborne illnesses.
However, foodborne illnesses can still be spread through international travel. Travelers can be exposed to contaminated food or water in other countries.

Therefore, safer food preparation practices do not eliminate the risk of foodborne illnesses being spread through international travel.