Listeria meningitis: report of ten recent cases and review of current therapeutic recommendations

Early trigeminal nerve involvement in Listeria monocytogenes rhombencephalitis: case series and systematic review

Listeria monocytogenes is associated with rhombencephalitis. However, the exact mechanisms of brainstem invasion remains poorly understood. Here, we demonstrate clinical and radiological data suggesting that Listeria may invade the brainstem via the trigeminal nerve. Three females (41, 64 and 70 years) with culture proven L. monocytogenes bacteremia and rhombencephalitis were investigated in the period of 2014-16. T2-weighted and contrast-enhanced T1-weighted MRI revealed a cerebellopontine abscess in all three patients, including the involvement of the trigeminal nerve root. In two patients, MRI also revealed selective contrast enhancement of the sensory trigeminal tract in the pons and medulla oblongata. Prior to any other neurological symptoms, two patients complained of hypoesthesia and a tingling sensation in the ipsilateral half of the face, consistent with sensory trigeminal nerve dysfunction on that side. In addition, we identified another 120 cases of Listeria rhombencephalitis following a systematic review. Cranial nerves VII, V, IX, and X, respectively, medulla oblongata, cerebellum and pons, were the most frequently involved brain structures. The present clinical and radiological findings corroborate earlier data from animal experiments, indicating that L. monocytogenes may be capable of retrograde intra-axonal migration along the cranial nerves. We suggest that in a subset of patients with rhombencephalitis L. monocytogenes enters the cerebellopontine angle through the trigeminal nerve, invading the brainstem via the sensory trigeminal nuclei.

Central nervous system infection with Listeria monocytogenes. 33 years' experience at a general hospital and review of 776 episodes from the literature

We reviewed 776 previously reported and 44 new cases of CNS listeriosis outside of pregnancy and the neonatal period, and evaluated the epidemiologic, diagnostic, and therapeutic characteristics of this infection. Among patients with Listeria meningitis/meningoencephalitis, hematologic malignancy and kidney transplantation were the leading predisposing factors, but 36% of patients had no underlying diseases recognized. The infection occurred throughout life, with a higher incidence before the age of 3 and after the age of 45-50 years. Fever, altered sensorium, and headache were the most common symptoms, but 42% of patients had no meningeal signs on admission. Compared with patients with acute meningitis due to other bacterial pathogens, patients with Listeria infection had a significantly lower incidence of meningeal signs, and the CSF profile was significantly less likely to have a high WBC count or a high protein concentration. Gram stain of CSF was negative in two-thirds of cases of CNS listeriosis. One-third of patients had focal neurologic findings, and approximately one-fourth developed seizures over their course. Mortality was 26% overall, and was higher among patients with seizures and those older than 65 years of age. Relapse occurred in 7% of episodes. Ampicillin for a minimum of 15-21 days (with an aminoglycoside for at least the first 7-10 days) remains the treatment of choice. Cerebritis/abscess due to L. monocytogenes, without meningeal involvement, is less common but may be diagnosed by blood cultures and CNS imaging, or by stereotactic biopsy. Longer antibiotic therapy (at least 5-6 weeks) is needed in the presence of localized CNS involvement.

Antimicrobial chemotherapy of human infection due to Listeria monocytogenes

Listeriosis is an uncommon infection, but when it occurs it carries a high mortality rate. Early diagnosis is essential and thereafter appropriate antimicrobial chemotherapy. Ampicillin or penicillin plus gentamicin remains the treatment of choice for most manifestations of listeriosis, and adequate doses must be given, i.e. greater than 6g/day of ampicillin or penicillin. Co-trimoxazole appears to be an excellent alternative agent with good penetration into the cerebrospinal fluid. Vancomycin is an appropriate agent for the treatment of primary bacteraemia but does not cross the blood-brain barrier sufficiently well to be useful in meningitis, while erythromycin may be used to treat listeriosis in cases of pregnancy. Treatment of bacteraemia requires one to two weeks' therapy, while meningitis cases may need to be treated for longer; for example, it has been found that most patients with acute meningitis in the UK were treated for 20 days. Infective endocarditis needs treatment for six to eight weeks. Doses should be varied with patients' altered organ function and antimicrobial serum monitoring performed when appropriate.

Spinal manifestation of neurolisteriosis

Spinal symptoms in acute bacterial meningitis are rare. In a series of 10 cases of neurolisteriosis, we observed 2 spinal complications, one due to an acute intramedullary abscess, the other caused by chronic spinal arachnoiditis. Therefore, if spinal symptoms develop in acute bacterial meningitis, Listeria monocytogenes infection should be considered and early adequate antibiotic treatment be implemented.

Susceptibilities of Listeria species isolated from food to nine antimicrobial agents

The agar dilution method was used to determine the activities of gentamicin, erythromycin, streptomycin, chloramphenicol, ampicillin, sulfamethazine, cephalothin, penicillin G, and tetracycline against 73 strains belonging to the genus Listeria (L. innocua, L. seeligeri, and L. monocytogenes). All strains were isolated from raw milk, cheese, the dairy processing plant, poultry, and the poultry slaughterhouse. Gentamicin, ampicillin, and erythromycin, of which the MICs for 90% of the strains tested for all three species were < or = 5.96 micrograms/ml, were found to be the most active agents studied. Most of the L. innocua strains isolated from poultry and the poultry slaughterhouse were resistant to tetracycline.

Listeria monocytogenes infection in prosthetic joints

Listeria monocytogenes is increasingly recognised as a cause of prosthetic joint infection. These infections tend to be more insidious and indolent in contrast to similar infections with Staphylococcus aureus. They can occur in patients who are immunocompromised due to malignancy or other illness or in nonimmunocompromised elderly patients. Listeria infections should not be treated with cephalosporins and prolonged antimicrobial treatment is generally advised for prosthetic joint infections. We noted a high affinity of L. monocytogenes for foreign bodies. Three of twenty-seven cases 11%) of listeriosis under the period of investigation were associated with foreign bodies (hip prosthesis, knee prosthesis and arterial graft).

Acute Therapy of Bacterial Meningitis

Antimicrobial therapy for bacterial meningitis has markedly reduced mortality rates from this disorder. The efficacy of an antibiotic in meningitis depends on many factors, including its penetration into cerebrospinal fluid (CSF), the bactericidal efficacy of the antibiotic within purulent CSF, and the need for bactericidal activity in CSF because bacterial meningitis represents an infection in an area of impaired host defense. Penicillin G and ampicillin are equally efficacious for meningitis caused by Streptococcus pneumoniae or Neisseria meningitidis. This recommendation may change, however, with the emergence of strains of pneumococci or meningococci that are relatively or highly resistant to penicillin; a third-generation cephalosporin (cefotaxime or ceftriaxone) should be used for meningitis due to relatively resistant strains and vancomycin for pneumococcal meningitis caused by strains that are highly resistant to penicillin. With the high percentage of strains of Haemopbilus influenzae type b that produce β-lactamase, empiric therapy when this organism is suspected should consist of a third-generation cephalosporin; these agents are also used for meningitis caused by enteric gram-negative bacilli, and one agent, ceftazidime, is effective against Pseudomonas aeruginosa meningitis. Despite the availability of effective bactericidal antibiotics, morbidity and mortality from bacterial meningitis remains unacceptably high. Recent studies using animal models of infection have demonstrated the beneficial effect of antiinflammatory agents in attenuating the CSF inflammatory response that may lessen many of the pathophysiological consequences of meningitis. Studies of adjunctive dexamethasone therapy suggest that these agents may reduce morbidity (specifically sensorineural hearing loss) and mortality (due to S. pneumoniae) in patients with bacterial meningitis. Controversy remains, however, concerning the use of dexamethasone in all patients with bacterial meningitis and further studies are necessary. In critically ill patients with bacterial meningitis, control of increased intracranial pressure and seizures may be useful and necessary in improving outcome.

Epidemiology of human listeriosis

During the 1980s, investigation of several large epidemics of listeriosis confirmed that transmission of L. monocytogenes in food causes human disease. Progress in laboratory detection and subtyping of the organism has enhanced our ability to compare human and environmental isolates of L. monocytogenes. Transmission by foodborne organisms is now recognized as causing both epidemic and sporadic listeriosis. Continued study of dietary risk factors associated with listeriosis is needed in order to develop dietary recommendations for the expanding population at increased risk of disease. Current research application of new molecular methods to the study of L. monocytogenes may improve the ability to diagnose pregnancy-associated disease and permit the rapid detection and control of L. monocytogenes in the food supply.

Dorsal midbrain encephalitis caused by Propionibacterium acnes. Report of two cases

A syndrome of dorsal midbrain dysfunction in association with a central nervous system anaerobic diphtheroid infection is described. Two cases of infection with Propionibacterium acnes manifested as shunt malfunctions with a clinical dorsal midbrain syndrome. Magnetic resonance images showed increased signal in the midbrain tectum which has decreased slowly over time. The evidence suggesting that this syndrome represents bacterial midbrain encephalitis is discussed.

Perinatal listeriosis in Dresden 1981-1986: clinical and microbiological findings in 18 cases

Between 1981 and 1986 Listeria monocytogenes was isolated from blood cultures, CSF, meconium/stools or external swabs from 18 newborn infants of two neonatal intensive care units (ICU) in adjacent pediatric clinics of Dresden. The epidemiological and clinical data of infants and their mothers, as well as microbiological and laboratory, x-ray, EEG and ultrasonic findings, are presented. All infants had an early onset of their disease. Cases were classified as granulomatosis infantiseptica (three cases), sepsis (three cases), meningitis (eight cases) and listerial infection without distinct organ manifestations (four cases), respectively. As far as the predominant symptoms at admission were concerned, no typical clinical signs of neonatal listeriosis could be evaluated. Cases with manifest clinical infections had an overall mortality rate of 21% (3/14) despite the immediate initiation of antibiotic therapy; at discharge, a further five patients showed neurological residuals. Serotyping and phagetyping have proved to be methods for recognition or exclusion of epidemiological relationships.

Listeria monocytogenes meningitis in previously healthy adults

A retrospective study of four sporadic cases of Listeria monocytogenes meningitis is reported. Contrary to the conventional epidemiology these patients were adults who were not immuno-compromised. Although all four cases produced positive cerebrospinal fluid cultures, in three, listeria was not microscopically identified. Protein and glucose contents of cerebrospinal fluids were variable and all samples showed lymphocytic pleocytosis. All four had neutrophil leucocytosis in peripheral blood. The unwary may dismiss lymphocytic meningitis as being of 'viral' origin, thereby making an important diagnostic misjudgement of vital therapeutic importance. Intravenous ampicillin is the drug of first choice for treatment of listeria meningitis; third generation cephalosporins are ineffective.

Outbreak of neonatal listeriosis in a regional hospital in Kuwait

Six newborns with Listeria monocytogenes infection were admitted to the same neonatal unit between 31 October and 3 December 1985. The index case, a preterm baby, was born to a mother who was febrile with an influenza-like illness at the time of delivery. This baby presented with Listeria sepsis and pneumonia. Another child was born from whose mother L. monocytogenes was isolated from the cervix with the same serotype as that in the CSF of her newborn. In the other cases blood and cervical cultures of the mothers were negative, while Listeria was isolated from the CSF of their babies. Five out of six infants developed meningitis between 9 and 12 days after birth. All isolates were serotype 4b and indistinguishable by phage typing. All babies were successfully treated without any major sequelae. Although cross-infection was strongly suggested, the source of the outbreak could not be established. This is the first documented report of human listeriosis in Kuwait.

Monoclonal antibodies show Listeria monocytogenes in necropsy tissue samples

Stable mouse monoclonal hybridoma cell lines secreting antibodies against Listeria monocytogenes were produced. Antibodies from two of these cell lines (designated CL2 and CL17) have been partially characterised. The specificities of these antibodies were assessed using indirect immunofluorescence antibody tests and L monocytogenes (166 strains) grown in vitro, other species of Listeria (21 strains), and bacteria from 14 other genera (87 strains). The antibodies were found to be specific for Listeria, and when used in combination, reacted with almost all strains of L monocytogenes. A simple and rapid direct immunofluorescence technique was developed, and the presence of L monocytogenes was shown in necropsy tissue from three patients where listeriosis had been confirmed by isolation of the bacterium. Bacteria were also confirmed using one of these antibodies in necropsy tissue from one further patient in whom listeriosis was suspected, but not confirmed by the cultivation of L monocytogenes.

Therapeutic activity of teicoplanin on experimental listeriosis compared with that of vancomycin and ampicillin

Several strains of Listeria monocytogenes and other Listeria spp. are without exception susceptible to teicoplanin (MIC 0.25 mg/l). Vancomycin as well as ampicillin are likewise active. A bactericidal effect of teicoplanin was only achieved at rather high concentrations and after incubation of several hours. There is no synergistic effect between teicoplanin and gentamicin. The therapeutic activity of teicoplanin as well as vancomycin in mice infected with L. monocytogenes is low. The efficacy of ampicillin could not be achieved. Treatment of chronically infected athymic, nude mice with teicoplanin is ineffective. Consequently, teicoplanin is not able to replace ampicillin in the therapy of listeriosis.

Listeria monocytogenes infections--therapeutic possibilities and problems

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.

Listeriosis in Ayrshire 1965-85

Twelve cases of listeriosis are described. Nine patients had meningitis, two primary listerial bacteraemia and one had bacteraemia from a focus of infection in the genito-urinary tract. Clinical presentation and treatment are described.

Neonatal listeriosis: a report of seven cases

Seven neonates with listeriosis admitted to Farwaniya Hospital, Kuwait, are reported. Six had the meningitic type and one the septicaemic type. Serotyping showed 1/4b in all neonates. The response to 2 weeks ampicillin and amikacin was excellent with no mortality or morbidity.

Lack of synergism of ampicillin and gentamicin in experimental listeriosis

Strain SLCC 4013 of Listeria monocytogenes is susceptible in vitro to ampicillin (MIC 0.5 mg/l) as well as to gentamicin (MIC 0.5 mg/l). Whereas treatment of mice infected with this virulent strain with 0.5 mg ampicillin twice a day resulted in a marked decrease in bacterial counts per spleen, the administration of 2 mg gentamicin twice a day hardly reduced bacterial multiplication. The combination of both drugs was not much more effective than ampicillin alone. Thus, a synergistic effect of both these antibiotics on intracellularly growing bacteria could not be demonstrated.