Final answer:
Jeni's condition is serious and requires antibiotic therapy with ampicillin and gentamicin.
Step-by-step explanation:
Jeni's condition of being infected with Listeria is serious as it can lead to listeriosis, a potentially life-threatening infection. The appropriate treatment for listeriosis involves antibiotic therapy, typically with ampicillin and an aminoglycoside antibiotic like gentamicin. This combination of antibiotics is effective in treating Listeria infections.