Listeriosis: therapeutic options.

Since overt listeriosis occurs mainly in immunocompromised persons it is quite consistent to try to restore the hampered defence system by supportive measurements. For direct antimicrobial treatment a series of different antibiotics is available, since Listeria strains isolated from patients are in general susceptible to a wide range of antibiotics, except fosfomycin, quinolones and cephalosporins of the third generation, although a few exceptional strains exist. Unfortunately, most antibiotics are not bactericidal for Listeria. Drug combinations may exert a synergistic effect. Furthermore, the efficacy of therapy is limited by the fact of intracellular habitat of pathogenic Listeria. Few agents, such as macrolides and quinolones, are accumulated within host cells and may attack the intracellular Listeriae. The clinical experience shows that the combination of amoxicillin and gentamicin is the best option.