An update on the medical management of listeriosis

Abstract

It is still not quite well understood why there is no optimal or even a satisfactory antibiotic therapy for listeriosis. Although almost all Listeria strains that induce sepsis, meningitis and encephalitis, as well as many other manifestations--in particular, in immunocompromised individuals--are susceptible to most of the common antibiotics, the cure rate is only approximately 70%. The most effective regimen still consists of a combination of an aminopenicillin (amoxicillin or ampicillin) plus an aminoglycoside. In vitro, this combination is bactericidal, whereas aminopenicillin alone only exerts a weak bactericidal activity against Listeriae. These antibiotics only poorly penetrate the cerebrospinal fluid and thus, only high doses given over a prolonged period of 2-3 weeks are curative. Furthermore, Listeria monocytogenes belongs to the group of facultative intracellular bacteria, which means that a certain population is inaccessible for antibiotics. Theoretically, a drug which is endowed with bactericidal activity superior to that of ampicillin would be preferable. Furthermore, the candidate drug should easily cross the blood-brain barrier into the CNS, be able to accumulate within host cells, reach the cytoplasm and be active under these unusual conditions. Because of all these arguments, the new quinolones are of particular interest; but broad clinical data are still lacking. It is unclear as to whether antibiotics alone will be sufficient to increase the prognosis. Adjunctive therapy with immunomodulators, which are able to reconstitute the defective defence capacities, would presumably create the conditions necessary to finally resolve listeriosis.

Characterization of antibiotic resistance in Listeria spp. isolated from slaughterhouse environments, pork and human infections

“…A positive outcome for listeriosis depends on the early administration of antibiotics. The standard treatment remains the application of high doses of a beta-lactam antibiotic (ampicillin or amoxicillin) alone or in combination with gentamicin; sulfamethoxazole is generally used in the case of betalactam intolerance [7].…”

Encefalitis del tallo cerebral y mielitis por Listeria monocytogenes: caso clínico y revisión del tema

“…Estos antibióticos penetran poco al líquido cefalorraquídeo; solo a dosis altas y por periodos prolongados de hasta cuatro semanas, son curativos. Otros antibióticos que tienen un poder bactericida mayor no transpasan la barrera hematoencefálica o la bacteria es resistente a ellos (16). En las guías de la Infectious Diseases Society of America (IDSA) del 2004, sobre el tratamiento de la meningitis bacteriana aguda, cuando se aísla L. monocytogenes en pacientes adultos, recomiendan como tratamiento de primera elección la ampicilina o la penicilina cristalina, y adicionar un aminoglucósido; como tratamientos alternativos recomiendan trimetoprim-sulfametoxazol o meropenem (17).…”

The use ofListeria monocytogenesas a DNA delivery vector for cancer gene therapy

“…It is known that single antibiotics administered in isolation are ineffective in controlling listeriosis, and currently the reference treatment in humans is based on synergistic combinations such as ampicillin and gentamicin administrated intravenously. 7 It has recently been shown in murine models that inclusion of one of the newer fluoroquinolones such as moxifloxacin cervical cancer and demonstrated the safety of an attenuated L. monocytogenes protein delivery vector in a vaccine setting. 14 The company behind that work (Advaxis Inc.,) is dedicated to the development of Listeria-based cancer vaccination strategies.…”