Final answer:
Oral Vancomycin is not well-absorbed and is not used for systemic conditions like endocarditis or sepsis; it is utilized for treating certain gastrointestinal infections, while intravenous Vancomycin is used for more severe systemic infections.
Step-by-step explanation:
Contrary to the student's assumption, oral Vancomycin is not easily absorbed when taken orally. It is usually reserved for treating conditions within the gastrointestinal tract. The main medical conditions that oral Vancomycin is used to treat are infections caused by Vancomycin-resistant Enterococci (VRE) and certain strains of Staphylococcus aureus, such as MRSA when other antibiotics are ineffective. Vancomycin is considered one of the last lines of defense against resistant infections.
Treatment for systemic infections such as endocarditis or sepsis often requires intravenous administration of Vancomycin, especially when high plasma levels are necessary to combat the infection. When Vancomycin is taken orally for such systemic infections, it would not be effective due to its poor absorption from the GI tract into the bloodstream.