Listeria infections

Amoxicillin-bearing microparticles: potential in the treatment of Listeria monocytogenes infection in Swiss albino mice

The present study was aimed at evaluating the effectiveness of amoxicillin-bearing HSA (human serum albumin) and PLGA [poly(lactic-co-glycolic acid)] microparticles in combating Listeria monocytogenes infection in Swiss albino mice. Amoxicillin-bearing HSA microspheres were prepared by chemical cross-linking of a drug/albumin mixture with glutaraldehyde, and PLGA microspheres were prepared by the W/O/W (water-in-oil-in-water) emulsion technique. The microspheres were characterized for their size, ζ potential and entrapment efficiency using SEM (scanning electron microscopy) and a Zetasizer. Release kinetics was performed in a phosphate buffer (pH 7.4) at 37°C simulating physiological conditions. Bacterial burden in various vital organs and survival data established enhanced efficacy of PLGA and HSA microspheres as compared with free drug. Among the two delivery systems, PLGA microspheres, when compared with HSA microspheres, imparted better efficacy in terms of reduction in bacterial load as well as increase in survival. The results of the present study clearly demonstrate that microparticles successfully target the infected macrophages and the approach could be well exploited for targeting the intracellular pathogens as well.

Listeriosis in human pregnancy: a systematic review

Listeria is commonly found in processed and prepared foods and listeriosis is associated with high morbidity and mortality. Preventative measures are well prescribed and monitoring and voluntary recall of contaminated products has resulted in a 44% reduction in the prevalence of perinatal listeriosis in the USA. Pregnant women are at high risk for listeriosis, but symptoms are non-specific and diagnosis is difficult. The intracellular life-cycle of Listeria protects the bacterium from host innate and adaptive immune responses. Antibiotic treatment requires agents able to penetrate, distribute, and remain stable within host cells. Prolonged use of high-dose ampicillin can significantly improve neonatal outcome.

Orthotopic Liver Transplantation: Is There a Risk for Listeria monocytogenes Infection?

Immunosuppression of any kind is a known risk factor for infection with Listeria monocytogenes (L. monocytogenes). Particularly, patients with impaired liver function are at increased risk of developing an aggravated course of infection with this bacterial pathogen (see Nolla-Salas et al.; 2002 and Cabellos et al.; 2008). It is a well-known pathogen in immunocompromised patients, but has only seldom been reported following orthotopic liver transplantation. Invasion of the central nervous system presenting as meningitis or meningoencephalitis and bacteremia are the principal clinical manifestations of listerial infections (see Brouwer et al.; 2006). We present an account of a case of a patient who developed L. monocytogenes meningitis during the early period after liver transplantation.

Early invasive Listeria monocytogenes infection after orthotopic liver transplantation: case report and review of the literature

Infection with Listeria monocytogenes is rare, with a reported annual incidence of 4.4 cases per million individuals. It is caused by a gram-positive rod-shaped bacterium (Listeria monocytogenes) that can be found in soil, vegetation, water, sewage, and silage and in feces of humans and animals. It is a facultative intracellular pathogen with the ability to survive and multiply in phagocytic host cells, even in adverse environmental circumstances. Listeriosis has rarely been reported after orthotopic liver transplantation, and transplant physicians are often unfamiliar with the clinical presentation of this rare but virulent infection, which accounts for 20%-30% mortality in affected individuals. We present a case of invasive Listeria infection causing bacteremia and peritonitis in the early postoperative period after cadaveric liver transplantation in a previously asymptomatic patient.

Listeria monocytogenes encephalitis mimicking Herpes Simplex virus encephalitis: the differential diagnostic importance of cerebrospinal fluid lactic acid levels

Listeria monocytogenes is a common cause of bacterial meningitis in elderly patients and in those with impaired cellular immunity. The most common central nervous system infection caused by L. monocytogenes is acute bacterial meningitis; meningoencephalitis is uncommon and encephalitis is rare. Early diagnosis of L. monocytogenes meningitis is difficult because only 50% of cerebrospinal fluid (CSF) Gram stains are negative. L. monocytogenes is one of the few central nervous system pathogens associated with red blood cells in the CSF. When L. monocytogenes presents as encephalitis with red blood cells in the CSF, the clinical presentation mimics most closely herpes simplex virus (HSV)-1 encephalitis. Because the therapies for L. monocytogenes and HSV-1 are different, early diagnostic differentiation is clinically important. The CSF lactic acid is the best way to rapidly differentiate between these two entities; the CSF lactic acid level is elevated in L. monocytogenes but is not elevated in HSV-1 encephalitis. The case presented is an elderly man with chronic lymphocytic leukemia who presented with encephalitis. Advanced age and chronic lymphocytic leukemia predispose him to a wide variety of pathogens, but the rapidity and severity of his clinical presentation made L. monocytogenes and HSV-1 encephalitis the most likely diagnostic possibilities. The CSF Gram stain was negative, but the elevated CSF lactic acid levels with encephalitis and red blood cells in the CSF indicated L. monocytogenes as the most likely pathogen. We present a case of L. monocytogenes encephalitis mimicking HSV-1 encephalitis. While receiving ampicillin therapy, the patient remained unresponsive for more than 1 week and then suddenly regained consciousness and recovered without neurologic sequelae.

Listeria monocytogenes following orthotopic liver transplantation: Central nervous system involvement and review of the literature

Listeria monocytogene is a well-recognized cause of bacteremia in immunocompromised individuals, including solid organ transplant recipients, but has been rarely reported following orthotopic liver transplantation. We describe a case of listeria meningitis that occurred within a week after liver transplantation. The patient developed a severe headache that mimicked tacrolimus encephalopathy, and was subsequently diagnosed with listeria meningitis by cerebrospinal fluid culture. The infection was successfully treated with three-week course of intravenous ampicillin. Recurrent hepatitis C followed and was successfully treated with interferon alfa and ribavirin. Fourteen cases of listeriosis after orthotopic liver transplantation have been reported in the English literature. Most reported cases were successfully treated with intravenous ampicillin. There were four cases of listeria meningitis, and the mortality of them was 50%. Early detection and treatment of listeria meningitis are the key to obtaining a better prognosis.

Listeria monocytogenes encephalitis mimicking West Nile encephalitis

We present a case of a 50-year-old man who presented to Winthrop-University Hospital in the midst of the 2002 West Nile encephalitis (WNE) outbreak with the cardinal clinical findings of WNE, ie, fever, encephalopathy, weakness, and muscle tremors. During the summer of 2002, several cases of aseptic meningitis/viral encephalitis were admitted to our emergency room weekly. In addition, cases of WNE were being admitted at the same time. During this period we had 3 cases of WNE. Our patient presented with the clinical findings of WNE. However, laboratory and radiologic findings suggested the possibility of Listeria monocytogenes encephalitis. The cerebrospinal fluid findings included red blood cells, which, in the absence of a traumatic tap or HSV encephalitis, argue against the diagnosis of WNE but are consistent with L. monocytogenes encephalitis. Computed tomography scan showed communicating hydrocephalus, which also suggests the possibility of L. monocytogenes and argued against the diagnosis of WNE. Clinicians should be vigilant for the mimics of WNE in geographical areas where WNE outbreaks are occurring.

Listeria monocytogenes infection in Israel and review of cases worldwide

Listeria monocytogenes, an uncommon foodborne pathogen, is increasingly recognized as a cause of life-threatening disease. A marked increase in reported cases of listeriosis during 1998 motivated a retrospective nationwide survey of the infection in Israel. From 1995 to 1999, 161 cases were identified; 70 (43%) were perinatal infections, with a fetal mortality rate of 45%. Most (74%) of the 91 nonperinatal infections involved immunocompromised patients with malignancies, chronic liver disease, chronic renal failure, or diabetes mellitus. The common clinical syndromes in these patients were primary bacteremia (47%) and meningitis (28%). The crude case-fatality rate in this group was 38%, with a higher death rate in immunocompromised patients.

Listeria infection after liver transplantation: report of a case and review of the literature

Listeria monocytogenes is a well-recognized cause of bacteremia and meningitis in immunocompromised individuals, including recipients of solid organ transplants, but has only rarely been reported following orthotopic liver transplantation (OLT). Most previously reported cases of listeriosis occurred months to years following liver transplantation; we describe a case of listeriosis that occurred within 1 wk of liver transplantation, shortly after discontinuation of trimethoprim-sulfamethoxazole prophylaxis, and review the English literature on Listeria infection after OLT. The patient developed abdominal pain and fever that suggested a bile leak, but was definitively diagnosed with Listeria infection by blood culture. The infection was successfully treated with 3 wk of intravenous ampicillin. We conclude that serious systemic infection with Listeria monocytogenes is uncommon following OLT, may occur early in the postoperative period, and responds well to treatment with high dose ampicillin.

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.

Recurrent Listeria monocytogenes bacteraemia in a liver transplant patient

We report a case of a recurrent Listeria monocytogenes bacteraemia in a 46 year-old liver transplant patient. Serotyping revealed that the two episodes of bacteraemia were caused by different strains. The possibility of a recrudescence of a persisting infection was rejected. We concluded that the recurrent bacteraemia in this predisposed patient was due to re-infection, and that antibiotic treatment (amoxicillin plus an aminoglycoside) resulted in a complete eradication of the infective microorganism. Therefore long-term suppressive antibiotic treatment was not indicated. The source of these L. monocytogenes infections was not found.

Spectrum and outcome of microbiologically documented listeria monocytogenes infections in cancer patients

At the M.D. Anderson Cancer Center (Houston), Listeria monocytogenes was cultured from 14 patients between 1980 and 1987. The case records of 11 of these patients were reviewed. Underlying malignancies included acute leukemia (three), lymphoma (two), myeloma (one), adenocarcinoma of colon (two), carcinoma of breast (one), carcinoma of lung (one), and Kaposi's sarcoma associated with the acquired immune deficiency syndrome (one). Listeria monocytogenes was cultured from blood (eight patients), cerebrospinal fluid (CSF) (two patients), and from both blood and CSF in one patient. All patients were receiving immunosuppressive therapy including corticosteroids in seven. An absolute neutrophil count of less than 1000/mm3 was noted in five. Bacteremia was the predominant type of infection and ten patients responded to antimicrobial therapy.

Listeriosis in the setting of malignant disease. Changing issues in an unusual infection

Thirteen cases of Listeria monocytogenes infection occurred at the Johns Hopkins Oncology Center over a 10-year period, representing 0.09% of all admissions. These cases principally occurred in patients with underlying hematologic of lymphoreticular malignancy, but in all patients other causes of immune suppression were also present. Corticosteroids were the most frequent exogenous cause of immune suppression. Bacteremia was detected more frequently than meningitis and in contrast to earlier reports, bacteriologic cure was achieved in 12 of 13 patients. Therapeutic success appeared to be related to early institution of effective antimicrobial agents. Despite eradication of infection, seven of the patients were dead within three months from progression of their underlying disease. The overall survival rate of cancer patients with listeriosis is therefore a function of the underlying malignancy and not the infection.

Determination of the effect of antimicrobics in combination against Listeria monocytogenes

The in vitro activity of selected penicillins, extended spectrum cephalosporins, vancomycin, gentamicin, erythromycin, tetracycline, rifampin, and trimethoprim and sulfamethoxazole (alone and in combination) was determined by microtiter technique for 20 isolates of Listeria monocytogenes. The activity of selected combinations of antimicrobics was determined by the microtiter checkboard technique. Trimethoprim-sulfamethoxazole (1:20 ratio) was the most active agent in inhibitory tests and also showed bactericidal activity. The combinations of gentamicin with either ampicillin or vancomycin and that of erythromycin with tetracycline showed bactericidal effect in synergy studies. Combining ampicillin with an extended spectrum cephalosporin showed no antagonism, whereas, combining rifampin with trimethoprim or with trimethoprim/sulfamethoxazole led only to indifference or antagonism. These observations may have importance in selection of therapy in animal models or in selected clinical situations.