Final answer:
The nurse should anticipate obtaining a stool specimen for culture to diagnose the cause of a patient's bloody diarrhea, identify the specific pathogen, and guide the treatment plan with appropriate antibiotics if necessary.
Step-by-step explanation:
A patient admitted to the emergency department with several episodes of bloody diarrhea should anticipate that the nurse will take action to potentially obtain a stool specimen for culture. This is important because the presence of blood can be associated with infections by certain pathogens, such as Campylobacter jejuni, Salmonella, and Entamoeba histolytica, which may require specific treatments. The stool sample can be analyzed using various techniques to identify the causative agent and determine the appropriate treatment plan. For instance, immunoassays could be used for Shigella dysenteriae, or molecular techniques like PCR to detect DNA sequences specific to the pathogen. Moreover, in severe cases or if systemic infection is present, antibiotics such as ciprofloxacin and azithromycin may be prescribed, though resistance issues must be considered.