Infectious Disease Treatment Practice Test 2026 – Complete Exam Prep

The first-line treatment for Listeria monocytogenes is intravenous ampicillin, often combined with gentamicin. Listeria is a type of bacteria that can cause serious infections, particularly in pregnant women, newborns, the elderly, and individuals with weakened immune systems.

Ampicillin is a penicillin antibiotic that is effective in targeting Listeria due to its ability to penetrate the bacterial cell wall. The combination of gentamicin provides a synergistic effect, enhancing the overall efficacy of treatment against this organism. This is especially important in severe cases such as meningitis, sepsis, or infections in immunocompromised patients, where achieving higher levels of bactericidal activity is crucial for effective management.

Other options like oral vancomycin and oral amoxicillin are not suitable as first-line treatments for Listeria. Vancomycin is more effective against certain gram-positive cocci, particularly Staphylococcus aureus and Streptococcus species, rather than Listeria. Oral amoxicillin, while it has some activity against Listeria, is generally not used for more severe infections where intravenous therapy is warranted.

Intravenous ceftriaxone is also typically not the first choice for Listeria,