Faropenem is the orally administered medicine and belongs to the 'penem' group to, which imipenem also belongs. Imipenem is given by injection and has been there for quite some years.
Faropenem is a Japanese research product and has not yet been cleared by US and other western drug regulators. Hence not much is known since it has not been in extensive use.
If no other antibiotic is effective, one has to take imipenem or feropenem if the germs are sensitive to it.