Listeria Monocytogenes Infection (Listeriosis) Medication

Updated: Aug 10, 2022
  • Author: Karen B Weinstein, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication Summary

Antibiotic therapy is the treatment of choice for listeriosis. Bacteremia should be treated for 2 weeks if the patient is immunocompetent. Longer courses may be required in the immunocompromised patient. Meningitis should be treated for 3 weeks; endocarditis, for 4-6 weeks; and brain abscess, for at least 6 weeks. Ampicillin is generally considered the preferred agent, but other agents may be acceptable. Gentamicin is added frequently for synergy, but it may be discontinued after 1 week of clinical improvement in order to decrease the chance of renal toxicity or ototoxicity. [22]

Glucocorticoids have not demonstrated benefit in Listeria meningitis. [23]



Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Ampicillin (Omnipen, Marcillin)

Ampicillin is the drug of choice. It interferes with bacterial cell wall synthesis during active multiplication, causing bactericidal activity against susceptible organisms.


Gentamicin is an adjunctive therapy that can be used in conjunction with ampicillin. It is an aminoglycoside antibiotic that interferes with bacterial protein synthesis by binding to the 30S and 50S ribosomal subunits. Dosing regimens are numerous and are adjusted based on creatinine clearance and changes in volume of distribution, as well as the body space into which the agent needs to distribute. Gentamicin may be given iIV/IM. Each regimen must be followed by at least a trough level drawn on the third or fourth dose, 0.5 hour before dosing; a peak level may be drawn 0.5 hour after a 30-minute infusion.

Trimethoprim-sulfamethoxazole (Bactrim)

This agent is indicated for patients unable to take penicillin antibiotics. It inhibits bacterial synthesis of dihydrofolic acid by competing with paraaminobenzoic acid, which results in inhibition of bacterial growth.