Which of the following nucleoside and nucleotide analogue can be used as an antibiotic?

Nucleosides and/or nucleotides are essential components of genetic material and are, therefore, intimately involved in the proliferation of cells. Fluorocytosine, can be used as an antibiotic because it is conveed into an active "nucleoside or nucleotide" only in bacteria. Human cells are not affected by its presence. Because analogues has its own special synthetic process, no other nucleotides and nucleosides are affected by the drugs. Aminopterin and methotrexate are also chemotherapy agents, which act by blocking folate addition to purine rings. Unlike fluorocytosine, though, these agents also affect rapidly dividing human cells such as hair and intestines, resulting in the common chemotherapy side effects of hair loss and nausea/vomiting. Ref: Janson L.W., Tischler M.E. (2012). Chapter 4. Nucleosides, Nucleotides, DNA, and RNA. In L.W. Janson, M.E. Tischler (Eds), The Big Picture: Medical Biochemistry.