A nurse is caring for a group of clients on an infectious disease unit. The nurse should wear an N95 respirator mask when caring for a client who has which of the following disorders?

Choice A rationale Mycoplasmal pneumonia is caused by Mycoplasma pneumoniae and is typically transmitted via large respiratory droplets. The appropriate precaution for this infection is droplet precautions, which require a standard surgical mask when within three to six feet of the patient. An N95 respirator is unnecessary because the pathogens are contained in heavy droplets that do not remain suspended in the air for long periods. Standard surgical masks provide sufficient filtration for these larger particles during routine care. Choice B rationale Scabies is an infestation of the skin by the Sarcoptes scabiei mite and is transmitted through direct, prolonged skin-to-skin contact or infested linens. Management requires contact precautions, including the use of gloves and gowns. Because scabies is not a respiratory or airborne pathogen, a mask is not required for protection unless the nurse is performing a task that involves splashing of other bodily fluids. An N95 respirator provides no specific benefit for preventing the transmission of skin parasites. Choice C rationale Scarlet fever, caused by group A Streptococcus, is transmitted through respiratory droplets. Similar to mycoplasmal pneumonia, it requires droplet precautions. The bacteria are spread when the infected individual coughs or sneezes, but the droplets are too large to remain airborne. A standard mask is the correct personal protective equipment. An N95 respirator is reserved for smaller particles that stay aloft, so it would be an excessive and incorrect choice for managing a client with scarlet fever. Choice D rationale Tuberculosis is caused by Mycobacterium tuberculosis, which is transmitted via the airborne route. These bacilli are contained in tiny droplet nuclei, measuring 1 to 5 micrometers, that can remain suspended in the air for hours and travel long distances. An N95 respirator is specifically designed to filter out at least 95 percent of these small airborne particles. Standard surgical masks are insufficient because they do not provide a tight facial seal or the filtration required to prevent inhalation of tuberculosis bacilli.