Listeria monocytogenes infections — Therapeutic possibilities and problems

Abstract

Listeriosis in humans is a rare disease, which, however, is known to be epidemic and endemic. The prognosis has remained unsatisfactory up to today, the fatality being at least 10% and often considerably higher depending on the clinical features of the disease and the patient's age. Three population groups are at risk: pregnant women, fetuses and newborn infants. Furthermore, immunosuppression in older patients due to disease, therapy, or age also plays a role. The incidence of Listeria infections in patients over 45 is clearly increasing. Due to the nature of the pathogen (in vivo bactericidal concentrations of antibiotics are often not attainable; intracellular growth) a high dosage of ampicillin is recommended. Although the present therapeutic possibilities are not satisfactory, a combination of ampicillin and an aminoglycoside appears to be the best therapy at present. Other combinations such as rifampicin and beta-lactam antibiotics have exhibited in vitro antagonism. The preferred therapy, ampicillin, can only be recommended with reservations because it is not optimally effective.

Rapid Eradication of Listeria monocytogenes by Moxifloxacin in a Murine Model of Central Nervous System Listeriosis

“…In contrast, amoxicillin has only slow and weak activity against intracytoplasmic reservoirs of bacteria, as only a small proportion of the drug reaches the cytoplasmic compartments of infected cells (7,14,25). Moreover, this may also have been due to the poor diffusion of amoxicillin into tissues, particularly into the cerebral parenchyma (17,23). Thus, high doses of amoxicillin are required to ensure sufficient concentrations at the sites of infection, as the in vivo efficacy of beta-lactams largely depends on the dose and the duration of treatment (16,23,40).…”

“…Moreover, this may also have been due to the poor diffusion of amoxicillin into tissues, particularly into the cerebral parenchyma (17,23). Thus, high doses of amoxicillin are required to ensure sufficient concentrations at the sites of infection, as the in vivo efficacy of beta-lactams largely depends on the dose and the duration of treatment (16,23,40).…”

“…Nevertheless, amoxicillin is also able to cure meningoencephalitis (3,17,26), but it seems to achieve this task rather late and only in cooperation with the immune system or in association with gentamicin, which is rapidly bactericidal in vitro even though it does not penetrate infected cells (16,40). Indeed, for immunocompromised mice, there is no apparent cure, as in these cases the role of antibiotics is much more decisive, especially rapid bactericidal activity (17,23,32).…”

Bay Y 3118, a new quinolone derivative, rapidly eradicates Listeria monocytogenes from infected mice and L929 cells

“…This regimen is, however, not satisfactory since about 30% of the patients treated in this manner die (6,8). Furthermore, recurrent listeriosis after inadequate therapy has been described (9).…”

Meningoencefalitis por Listeria en el lupus

“…Son necesarias altas dosis de ampicilina, sobretodo cuando hay afectación cerebral, ya que ésta cruza la barrera hemato-encefálica de una manera muy pobre, siendo necesario en adultos dosis no menores a 6 g/día (14).…”