Nitrofurantoin is an antibacterial agent specific for urinary tract infections. Nitrofurantoin is highly soluble in urine, to which it may impart a brown color. Nitrofurantoin inactivates or alters bacterial ribosomal proteins and other macromolecules. Nitrofurantoin has been shown to be active against the following bacteria: Gram-Positive Aerobes Staphylococcus saprophyticus, Coagulase-negative staphylococci (including Staphylococcus epidermidis), Enterococcus faecalis, Staphylococcus aureus, Streptococcus agalactiae, Group D streptococci, Viridans group streptococci. Gram-Negative Aerobes- Escherichia coli, Citrobacter amalonaticus, Citrobacter diversus, Citrobacter freundii, Klebsiella oxytoca, Klebsiella ozaenae.