Final answer:
The most convenient and appropriate route for home administration of an antimicrobial to treat a systemic infection is oral administration.
Step-by-step explanation:
The subject of the question is medicine, specifically relating to the administration of medications. The appropriate route for administering an antimicrobial to treat a systemic infection that would be suitable for home use is the oral route.
This method is generally considered safe, convenient, and does not require professional medical assistance. Intravenous administration requires professional equipment and personnel, making it unsuitable for home use. Topical applications are not systemic but local, and the parenteral route is a general category that includes intravenous, intramuscular, and subcutaneous, all typically requiring professional assistance.