Source tracking on a dairy farm reveals a high occurrence of subclinical mastitis due to hypervirulent Listeria monocytogenes clonal complexes.

AIMS: An extensive source investigation was conducted on a dairy farm with neurolisteriosis and subclinical mastitis cases to identify infection source and potential transmission routes of Listeria monocytogenes. METHODS AND RESULTS: A total of 36 L. monocytogenes isolates were obtained from animal clinical cases (neurolisteriosis and udder infection) and the farm environment (silage, faeces, water). Isolates were typed using pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS). Their virulence potential was assessed using the gentamicin protection assay and WGS-based identification of virulence genes. PFGE and WGS revealed a high genetic diversity of L. monocytogenes. An epidemiological link was confirmed for isolates from (i) several subclinical mastitis cases, (ii) silage and subclinical mastitis cases and (iii) different water sources. The neurolisteriosis isolate belonged to clonal complex (CC) 1, but infection source was not identified. A high occurrence (9/47 cows; 19·1%) of subclinical mastitis was observed with isolates belonging to CC2, CC4 and CC11. CONCLUSIONS: The dairy farm environment was contaminated with diverse L. monocytogenes strains, including genotypes associated with human disease. Several isolates harboured genetic determinants associated with increased infectious potential in humans. SIGNIFICANCE AND IMPACT OF THE STUDY: Results suggest that subclinical listerial mastitis should not be neglected as a potential source of milk contamination. The presence of hypervirulent CCs in subclinical mastitis cases calls for the implementation of improved mastitis detection.

Predictive risk factors for Listeria monocytogenes meningitis compared to pneumococcal meningitis: a multicenter case-control study.

PURPOSE: Various immunocompromised conditions increase the risk of meningitis caused by Listeria monocytogenes. However, the relative importance of these risk factors has not been well established. We determined the risk factors that predict meningitis due to L. monocytogenes compared to that caused by Streptococcus pneumoniae. METHODS: A nationwide multicenter case-control study was conducted in Korea. Cases of meningitis caused by L. monocytogenes between 1998 and 2013 were included. Patients with pneumococcal meningitis were included as controls. Multivariate logistic regression analysis was used to predict the risk factors of Listeria meningitis. RESULTS: A total of 36 cases and 113 controls were enrolled. The most significant predictive risk factor of Listeria meningitis was a prior history of receiving immunosuppressive therapy (odds ratio 8.12, 95 % CI 2.47-26.69). Chronic liver disease was the second most important predictive risk factor (OR 5.03, 95 % CI 1.56-16.22). Delaying appropriate antibiotic therapy by more than 6 h (hazard ratio 2.78) and fatal underlying disease (hazard ratio 2.88) were associated with increased mortality. CONCLUSIONS: Patients with a prior history of receiving immunosuppressive therapy within 1 month and chronic liver disease have 8.1-fold and 5-fold increased risk of meningitis by L. monocytogenes compared to S. pneumoniae, respectively.

The clinical features, diagnosis, treatment, and prognosis of neuroinvasive listeriosis: a multinational study.

The aim of this study was to determine the independent risk factors, morbidity, and mortality of central nervous system (CNS) infections caused by Listeria monocytogenes. We retrospectively evaluated 100 episodes of neuroinvasive listeriosis in a multinational study in 21 tertiary care hospitals of Turkey, France, and Italy from 1990 to 2014. The mean age of the patients was 57 years (range, 19-92 years), and 64% were males. The all-cause immunosuppression rate was 54 % (54/100). Forty-nine (49 %) patients were referred to a hospital because of the classical triad of symptoms (fever, nuchal rigidity, and altered level of consciousness). Rhombencephalitis was detected radiologically in 9 (9 %) cases. Twenty-seven (64 %) of the patients who had cranial magnetic resonance imaging (MRI) performed had findings of meningeal and parenchymal involvement. The mean delay in the initiation of specific treatment was 6.8 ± 7 days. Empiric treatment was appropriate in 52 (52 %) patients. The mortality rate was 25 %, while neurologic sequelae occurred in 13 % of the patients. In the multivariate analysis, delay in treatment [odds ratio (OR), 1.07 [95 % confidence interval (CI), 1.01-1.16]] and seizures (OR, 3.41 [95 % CI, 1.05-11.09]) were significantly associated with mortality. Independent risk factors for neurologic sequelae were delay in treatment (OR, 1.07 [95 % CI, 1.006-1.367]) and presence of bacteremia (OR, 45.2 [95 % CI, 2.73-748.1]). Delay in the initiation of treatment of neuroinvasive listeriosis was a poor risk factor for unfavorable outcomes. Bacteremia was one of the independent risk factors for morbidity, while the presence of seizures predicted worse prognosis. Moreover, the addition of aminoglycosides to ampicillin monotherapy did not improve patients' prognosis.

Clinical characteristics and prognosis of pediatric Listeria monocytogenes meningitis based on 10-year data from a large children's hospital in China.

This study aims to summarize the clinical characteristics and prognosis of Listeria monocytogenes (LM) meningitis in children in Chongqing, China. A retrospective analysis of the clinical data and follow-up results of 20 LM meningitis patients admitted to the Children's Hospital of Chongqing Medical University (CHCMU) from January 2012 to December 2022 was performed. The LM meningitis incidence rate was between 0 and 14.3 per 100,000 persons. The median age at onset was 8.98 months. There were five neonate cases, which all had perinatal abnormalities. Seven non-neonatal cases (7/15, 46.7%) had a documented history of contaminated food intake. One case had primary immunodeficiency. The most common symptoms were fever (20/20), altered consciousness (19/20), and vomiting (15/20). Seven cases had seizures, eight cases had cranial nerve involvement, eight cases had positive Babinski sign, and 10 cases had positive meningeal signs. The most common complications were hyponatremia (6/20), hypokalemia (6/20), respiratory failure (5/20), subdural effusion (3/20), and hydrocephalus (2/20). Treatment primarily involved monotherapy or combination therapy with meropenem (15/20) and ampicillin (10/20). Fifteen cases were treated with monotherapy or combination therapy using vancomycin. Twelve cases were successfully followed up from 10 months to 9 years and 6 months, and all had favorable long-term outcomes. LM meningitis incidence in children is low and with nonspecific clinical manifestations. Strengthening food hygiene and safety education, and avoiding infections during pregnancy are important to prevent LM infection in neonates and high-risk individuals. Meropenem and ampicillin are the preferred treatments. Early diagnosis and treatment can improve prognosis.IMPORTANCEThe incidence of LM meningitis is extremely low, and there is currently no standardized treatment. We conducted a retrospective analysis of ten years of data from CHCMU regarding diagnosed LM meningitis cases, aiming to provide clinical evidence for the diagnosis and treatment.

Listeria monocytogenes sequence type 6 and increased rate of unfavorable outcome in meningitis: epidemiologic cohort study.

BACKGROUND: We analyzed clinical characteristics, treatment, genetic diversity, and outcome of 92 adults with Listeria monocytogenes meningitis included in 2 prospective nationwide cohort studies. METHODS: Episodes of community-acquired listerial meningitis confirmed by cerebrospinal fluid culture were included from 1998 to 2002 and 2006 to 2012. We compared patients and pathogen characteristics between cohorts and identified predictors for an unfavorable outcome according to the Glasgow Outcome Scale. RESULTS: Thirty episodes were included from 1998 to 2002 and 62 from 2006 to 2012; clinical and laboratory characteristics on admission were similar between cohorts. However, the rate of unfavorable outcome increased from 27% in the 1998-2002 cohort to 61% in the 2006-2012 cohort (P = .002). Differences between cohorts were increased use of adjunctive dexamethasone therapy (0% in 1998-2002 vs 53% in 2006-2012; P < .001) and emergence of infection by L. monocytogenes genotype sequence type 6 (ST6; 4% in 1998-2002 vs 29% in 2006-2012; P = .009). Multivariate regression analysis identified infection with L. monocytogenes ST6 as the sole predictor of unfavorable outcome (odds ratio, 3.77; 95% confidence interval, 1.07-13.33). Patients infected with genotypes other than ST6 also had an increased rate of unfavorable outcome over time (P = .03). CONCLUSIONS: The rate of unfavorable outcome among adults with listerial meningitis has increased over a 14-year period, from 27% to 61%. The emerging L. monocytogenes genotype ST6 was identified as the main factor leading to poorer prognosis. Adjunctive dexamethasone may be discontinued if L. monocytogenes is identified, as there is no proven benefit in Listeria meningitis.

[Nosocomial outbreak due to Listeria monocytogenes in a neonatal unit]. / Brote nosocomial por Listeria monocytogenes en una Unidad de Neonatos.

INTRODUCTION: Description of an outbreak of Listeria monocytogenes in a neonatal intensive care unit. METHODS: A questionnaire, environmental investigation and molecular study were performed. RESULTS: We identified a nosocomial outbreak of L. monocytogenes, confirmed by the genetic study, in a neonatal intensive care unit. Three infants were affected. Although the transmission mechanism could not be elucidated, cross-infection was strongly suggested. CONCLUSION: Adherence to universal hygiene standards is necessary to avoid nosocomial outbreaks.

[Listeriosis in Tunis: seven cases reports]. / Les infections à Listeria monocytogenes à Tunis: à propos de sept cas.

Listeria monocytogenesis a Gram positive facultative intracellular bacterium that can be responsible for severe infections, affecting essentially pregnant women, immunocompromised patients at the early and later stages of life. In Tunisia, invasive L. monocytogenes infections are thought to be exceptional and limited data are available about listeriosis. We reported seven cases (five newborn children and two infants) of human listeriosis that occurred in Tunis from 2000 to 2008. The newborn children were hospitalized for suspicion of maternofoetal infections. The two infants were hospitalized for fever associated with digestive signs in one case and neurological signs in the other. L. monocytogenes-was isolated from culture of cerebrospinal fluid in four cases, peripheral samples in two cases and from blood culture in one case. Isolates identification was based on conventional methods. Antimicrobial susceptibility was realized according to the recommendation of the "Comité de l'antibiogramme de la Société française de microbiologie". All L. monocytogenes isolates were sensitive to amoxicillin and aminoside but resistant to 3rd generation cephalosporins. Investigations of the immune system were realized for the two infants including phenotypic analysis of peripheral blood cells by flow cytometry, lymphocyte proliferation assays, phagocytic cell functions and measurement of immunoglobulins as well as complement. All these explorations were normal for both infants. The outcome was fatal in only one case (a newborn child), and all the other patients recovered after adapted antibiotic treatment. In conclusion, our study shows that listeriosis is not exceptional in Tunis. Thus, it is necessary to know how to evoke this diagnosis, at any age, in order to establish an early and adapted antibiotic treatment and to avoid fatal outcome.

Neonatal Listeria-meningitis in San Luis, Argentina: a three-case report.

Between November 1996 and December 2006, two cases of early-onset and one case of late-onset neonatal listeriosis were reported in San Luis, Argentina. This article describes clinical and laboratory findings as well as treatment and outcome for newborns treated for Listeria monocytogenes meningitis or septicaemia. In one of the newborns with early-onset listeriosis, meningitis led to important complications including hydrocephalus. The two other newborns showed complete recovery following adequate treatment. The L. monocytogenes isolates from two patients belonged to PCR group IVb (including serovar 4b strains) and to PCR group IIb (including serovar 1/2b strains) in the third patient. Listeriosis, especially the maternal-fetal presentation, is still rare in Argentina for unknown reasons. Our data can be used in the future as an epidemiological survey.

[Listeriosis of the central nervous system: epidemiological and diagnostic aspects--own observations]. / Listerioza osrodkowego ukladu nerwowego: aspekty epidemiologiczne i diagnostyczne--obserwacje wlasne.

UNLABELLED: The aim of the study was to evaluate clinical and laboratory findings and predisposing factors for Listeria monocytogenes (Lm) meningitis. METHODS: 17 intensive care unit patients (12 M, 5 F), aged 54.4 +/- 15.3 yrs, were studied. CNS listeriosis was confirmed by culture of cerebrospinal fluid (CSF) or CSF pleocytosis coupled with Lm bacteriemia. RESULTS: The frequency of central nervous system (CNS) listeriosis among patients with bacterial meningitis was 5.5%. Meningeal signs were present in all patients. 15 patients had impaired level of consciousness. Possible predisposing factors occurred in 15 patients. The average CSF white blood cell count was 1034 +/- 1064 cells/microl. CONCLUSION: Symptoms and signs of patients with CNS listeriosis were not different from those usually found in other bacterial meningitis. A trend toward fewer WBC in CSF was revealed. Most patients with Lm meningitis were immunocompromised.

Characteristics and Outcomes of Neonates With Blood Stream Infection Due to Listeria monocytogenes.

BACKGROUND: Infection due to Listeria monocytogenes (LM) is rare in neonates; thus, its clinical presentation and outcomes are not commonly reported, especially in low- and middle-income countries. In 2017, South Africa had an outbreak due to LM. OBJECTIVE: To determine demographic characteristics, clinical and laboratory findings and outcomes of all neonates infected with LM during the outbreak period. METHODS: This is a retrospective analytic study. Clinical and laboratory records of neonates admitted at Chris Hani Baragwanath Academic Hospital from January 2017 to May 2018 with positive blood and cerebrospinal fluid culture with LM were reviewed for demographic characteristics, clinical presentation, ancillary laboratory test results and outcomes at hospital discharge. RESULTS: There were 42 neonates with positive cultures due to LM. Thirty-four (81%) were born preterm. Mode of delivery was vaginal in 78.6% and 31.0% were HIV exposed. All patients presented within the first 6 days of life as an early-onset disease. Common clinical presentation was respiratory depression (52.4%) and respiratory distress (38.1%) with 69% requiring invasive or noninvasive respiratory support. Common abnormal laboratory findings were high C-reactive protein (77.1%) followed by leukopenia (23.8%). Fourteen patients (40%) had features of meningitis based on blood and cerebrospinal fluid findings (4 culture proven). There were 11 deaths at hospital discharge, giving a mortality rate of 26.2%. CONCLUSIONS: The majority of neonates infected with LM were born preterm, raising the possibility that LM itself may have been responsible for preterm labor. All presented in the first 6 days of life and most presented with respiratory distress or depression. A high proportion had meningitis, and there was a high-mortality overall.

Three-year multicenter surveillance of community-acquired Listeria monocytogenes meningitis in adults.

BACKGROUND: Listeria monocytogenes is the third most frequent cause of bacterial meningitis. The aim of this study is to know the incidence and risk factors associated with development of acute community-acquired Lm meningitis in adult patients and to evaluate the clinical features, management, and outcome in this prospective case series. METHODS: A descriptive, prospective, and multicentric study carried out in 9 hospitals in the Spanish Network for Research in Infectious Diseases (REIPI) over a 39-month period. All adults patients admitted to the participating hospitals with the diagnosis of acute community-acquired bacterial meningitis (Ac-ABM) were included in this study. All these cases were diagnosed on the basis of a compatible clinical picture and a positive cerebrospinal fluid (CSF) culture or blood culture. The patients were followed up until death or discharge from hospital. RESULTS: Two hundred and seventy-eight patients with Ac-ABM were included. Forty-six episodes of Lm meningitis were identified in 46 adult patients. In the multivariate analysis only age (OR 1.026; 95% CI 1.00-1.05; p = 0.042), immunosuppression (OR 2.520; 95% CI 1.05-6.00; p = 0.037), and CSF/blood glucose ratio (OR 39.42; 95% CI 4.01-387.50; p = 0.002) were independently associated with a Lm meningitis. The classic triad of fever, neck stiffness and altered mental status was present in 21 (49%) patients, 32% had focal neurological findings at presentation, 12% presented cerebellum dysfunction, and 9% had seizures. Twenty-nine (68%) patients were immunocompromised. Empirical antimicrobial therapy was intravenous ampicillin for 34 (79%) of 43 patients, in 11 (32%) of them associated to aminoglycosides. Definitive ampicillin plus gentamicin therapy was significantly associated with unfavourable outcome (67% vs 28%; p = 0.024) and a higher mortality (67% vs 32%; p = 0.040).The mortality rate was 28% (12 of 43 patients) and 5 of 31 (16.1%) surviving patients developed adverse clinical outcome. CONCLUSIONS: Elderly or immunocompromised patients, and a higher CSF/blood glucose ratio in patients with Ac-ABM must alert clinicians about Lm aetiology. Furthermore, we observed a high incidence of acute community-acquired Lm meningitis in adults and the addition of aminoglycosides to treatment should be avoid in order to improve the patients' outcome. Nevertheless, despite developments in intensive care and antimicrobial therapy, this entity is still a serious disease that carries high morbidity and mortality rates.

Etiology, clinical presentation, outcome and the effect of initial management in immunocompromised patients with community acquired bacterial meningitis.

OBJECTIVES: The aim was to analyze differences in clinical presentation, etiology, management, and outcome between immunocompromised and immunocompetent patients with acute bacterial meningitis (ABM). METHODS: Data were extracted from 1056 adult ABM patients prospectively registered in the national Swedish quality register for ABM during 2008-2017. Primary endpoint was 30-day mortality and secondary endpoints 90-day mortality and unfavorable outcome. RESULTS: An immunocompromised state was observed in 352 (33%) of the 1056 patients. Streptococcus pneumoniae dominated in both immunocompromised and immunocompetent patients (53% in both groups), whereas L monocytogenes occurred in 11% and 2%, respectively. The unadjusted odds ratio (OR) for 30-day mortality in immunocompromised compared to immunocompetent patients was 1.68 (95% confidence interval (CI): 1.07-2.63). Adjusted for age, sex, and mental status on admission the OR was 1.34 (CI: 0.82-2.21). Adjusted also for time to antibiotic treatment and corticosteroids the OR was 1.10 (CI: 0.59-2.05), and in patients without Listeria meningitis 0.98 (CI: 0.50-1.90). Although, the ORs were higher for 90-day mortality and unfavorable outcome the effects of adjustments were similar. CONCLUSION: Mortality in immunocompromised patients with ABM is only moderately increased unless caused by Listeria. This difference is further reduced in patients given early antibiotic treatment and adjunctive corticosteroids. FUNDING: This work was supported by Stockholm County Council.

High incidence of severe neurological manifestations and high mortality rate for adult Listeria monocytogenes meningitis in Taiwan.

The clinical characteristics and therapeutic outcomes of adult Listeria monocytogenes meningitis are not commonly examined in isolation in the literature. During a study period of 19 years (2000-2018), 366 patients with culture-proven adult bacterial meningitis (ABM) were identified in the author's hospital (264 patients in 2000-2010 and 102 patients in 2011-2018). Of the 366 ABM patients, 330 had monomicrobial infections while the other 36 had mixed infections. L. monocytogenes infection was identified in 11 of the 330 patients with monomicrobial ABM (3 in 2000-2010 and 8 in 2011-2018). These 11 patients included 5 males and 6 females, aged 47 to 76 years (median age = 61.7). None of the 11 patients had a postneurosurgical state as the underlying cause, but 3 of them contracted the infection nosocomially. Common underlying conditions included liver cirrhosis (4), systemic malignancy (3), diabetes mellitus (3), and renal disease (2). The most common clinical manifestations were fever (11), altered consciousness (8), seizure (8), bacteremia (7) and hydrocephalus (5). The therapeutic result revealed a mortality rate of 72.7% (8/11), but no significant prognostic factors were identified. The clinical features of 8 additional Taiwanese L. monocytogenes ABM patients reported in the literature, were also included for analysis. The present study revealed an increase in L. monocytogenes ABM in recent years and most patients presented with severe neurological manifestations. The current study is a preliminary overview of L. monocytogenes meningitis in adults and a further large-scale study is needed for improved delineation of this specific infectious syndrome.

An outbreak of febrile gastroenteritis associated with jellied pork contaminated with Listeria monocytogenes.

In September 2008, the Austrian Agency for Health and Food Safety (AGES) learned of an outbreak of diarrheal illness that included a 71-year-old patient hospitalized for gastroenteritis with a blood culture positive for Listeria monocytogenes. Three stool specimens provided by seven of 19 persons attending a day trip to a foreign city, including a final break at an Austrian tavern, yielded L. monocytogenes. All isolates were of serovar 4b and had fingerprints indistinguishable from each other. A cohort study revealed that the outbreak of gastroenteritis occurred among 16 persons who had eaten dinner at the wine tavern on September 6. Of the 15 persons who ate from platters of mixed cold-cuts, 12 (80%) developed symptoms of febrile gastroenteritis within 24-48 h. The median age of those who became ill was 62 years. A 72-year-old patient recovered from gastroenteritis but was hospitalized with bacterial meningitis on day 19 after the dinner. The epidemiological investigation identified the consumption of mixed cold-cuts (including jellied pork) at the wine tavern as the most likely vehicle of the foodborne outbreak (P = 0.0015). This hypothesis was confirmed by microbiological investigation of jellied pork produced by the tavern owner on September 3. L. monocytogenes was isolated from leftover food in numbers of 3 x 10(3)-3 x 10(4) colony forming units/g and was indistinguishable from the clinical outbreak isolates. Symptoms reported by the 12 patients included unspecified fever (12x), diarrhea (9x), headache (5x), vomiting (4x), body aches (2x) and sore throat (1x). Active case finding identified one case of rhombencephalitis (female, age 48) among another group of four guests, among whom only the patient and her asymptomatic husband had eaten jellied pork on September 6. This is the first outbreak of L. monocytogenes-associated gastroenteritis reported in Austria. The occurrence of a secondary case of meningitis (diagnosed on day 19 after consumption of jellied pork) indicates a significant risk of systemic listeriosis among elderly patients with febrile gastroenteritis caused by L. monocytogenes; antibiotic therapy should therefore be considered in such cases of documented listerial gastroenteritis.

Listeria Meningitis in Danish Children 2000-2017: A Rare Event Even in a Country With High Rates of Invasive Listeriosis.

Listeria monocytogenes meningitis in Danish children 1 month to 17 years from 2000 to 2017 was identified and patient files reviewed. There were 5 cases, equaling an annual incidence of 0.024 per 100,000 children or 0.014 when excluding 2 immunodeficient children. Even in a country with a high general incidence of listeriosis, Listeria meningitis is a rare event in healthy children.

The clinical course and outcome of Listeria monocytogenes meningitis: A retrospective single center study.

BACKGROUND: The aim of the study was to determine clinical manifestations and outcome of Listeria monocytogenes meningitis (LM) and to compare with other forms of bacterial meningitis (BM). MATERIAL AND METHODS: We analyzed records of all adult patients with BM who were hospitalized between January 2010 and December 2017 in the largest neuroinfection center in Poland. RESULTS: Out of 343 analyzed patients with BM 24 were diagnosed to have LM. Patients with LM were older compared to patients with other forms of BM (62 years vs. 57 years, p=0.039), were more likely to have cancer (16.7% vs. 4.7%, p=0.045), receive immunosuppressive treatment (45.8% vs. 10.7%, p<0.001), or be immunocompromised in any way (62.5% vs. 35.5%, p=0.016). Blood tests showed lower WBC (10.7 × 103 cells/µl vs. 15.5 × 103 cells/µl, p=0.004), C-reactive protein (150 mg/L vs. 221 mg/L, p=0,019) and procalcitonin (1.27 ng/mL vs. 3.78 ng/mL, p=0.003) in LM group. Analysis of cerebrospinal fluid showed lower cell count (531.5 cells/µL vs. 1100 cells/µL, p<0.001) and lower chloride (113 mmol/L vs. 117 mmol/L, p=0.036) in patients with LM. In the multiple logistic regression analysis, immunosuppressive therapy was the only variable independently associated with LM (OR:8.72, CI 95%:1.41-64.34, p=0.024). CONCLUSIONS: LM is associated with older age, cancer and immunosuppressive therapy. However, in multivariate analysis only immunosuppressive therapy turned out to be an independent risk factor for LM.

[Listeria monocytogenes meningitis in children in France]. / Méningites à Listeria monocytogenes de l'enfant en France.

UNLABELLED: Listeriosis is a serious invasive disease which affects mainly pregnant women, newborns and immunocompromised adults. OBJECTIVE: To analyze specifically the epidemiological and clinical data of the meningitis due to Listeria monocytogenes (Lm), from the French Network of Surveillance of Bacterial Meningitis in childhood. PATIENTS AND METHODS: Patients were aged 0 to 18 years. The diagnosis was based on a combination of a feverish meningeal syndrome and a positive culture of cerebrospinal fluid (CSF) and/or a positive PCR in the CSF and/or positive blood culture associated with a pleiocytose. RESULTS: Among 2539 cases of bacterial meningitis recorded in 6 years (2001 to 2006), 18 cases were due to Lm (0.7 %) (sex ratio M / F : 0.8). The average of age was 2.5 years (median : 0.5 ; ext : 0-15.1). The serotype of Lm was 4B in half of the cases. Most cases have occured in summer and autumn. Two patients presented an acquired or congenital immunodeficiency. Fifty-six percent (n=10) were younger than 1 year, among them, 7 were newborns. The CSF direct microbiologic investigation was suggestive of Lm (Gram positive bacilli) only in two cases, but the culture of CSF was positive for 16 patients and the blood culture was positive for 2 other patients. Three of 18 patients died between 7 and 13 days after admittance : a premature baby of 25 weeks'gestational age, two full-term newborns of 2 days and 1.5 months old. The mortality rate was 16.7 % before the age of 1 year (no death after this age). CONCLUSION: Meningitis due to Lm remains a rare disease, including in neonatal period. The recent increase of cases in adults requires to maintain vigilance in children especially since direct examination of CSF can rarely allow the diagnosis.

Meningitis por Listeria: serie de casos en un hospital de tercer nivel y utilidad de las nuevas técnicas de diagnóstico microbiológico / Listeria meningitis: case series in a tertiary level hospital and the usefulness of new microbiological diagnostic techniques

Introducción: La meningitis por Listeria monocytogenes (MLM) es una entidad grave con complicaciones a corto plazo. La reacción de polimerasa en cadena (RPC) puede ayudar a mejorar su diagnóstico y pronóstico. Objetivos: Conocer las características de los pacientes diagnosticados de meningitis por L. monocytogenes en los últimos años, a través de diferentes métodos microbiológicos. Pacientes y Métodos: Serie de casos de pacientes adultos ingresados con MLM en el Hospital Clínico San Carlos, Madrid, España, durante doce años (2009-2021). Se describieron variables epidemiológicas, clínicas, microbiológicas, radiológicas y terapéuticas. Resultados: Se registraron doce pacientes con MLM (edad media 67,5 años, 75% varones). En ocho se obtuvo un cultivo positivo a L. monocytogenes. La RPC en líquido cefalorraquídeo (LCR) fue positiva en los dos casos en los que se realizó la prueba. El tratamiento dirigido en todos los casos fue ampicilina durante 21 días. Se registraron complicaciones en un cuarto de los casos. Del total de pacientes uno falleció. Conclusiones: La MLM es una enfermedad poco frecuente y de difícil diagnóstico. En nuestra serie de casos los dos pacientes diagnosticados por RPC tuvieron resultado de cultivo de LCR negativo, y presentaron buena evolución. La determinación de RPC podría permitir diagnosticar un mayor número de casos y con mayor precocidad.

Background: Listeria monocytogenes meningitis (LMM) is a serious entity with short-term complications. Polymerase chain reaction (PCR) can help to improve its diagnosis and prognosis. Aim: To know the characteristics of patients diagnosed with meningitis by L. monocytogenes in recent years, through different microbiological methods. Methods: Case series of adult patients admitted with LMM at the Hospital Clínico San Carlos of Madrid, Spain, during twelve years (2009-2021). Epidemiological, clinical, microbiological, radiological and therapeutic variables were described. Results: Twelve patients with LMM were recorded (mean age 67.5 years, 75% male). Eight had a positive culture for L. monocytogenes. cerebrospinal fluid (CSF) PCR was positive in the two cases in which the test was performed. Treatment in all cases was ampicillin for 21 days. Complications were recorded in a quarter of the cases. One patient died. Conclusions: LMM is a rare and difficult to diagnose disease. In our series of cases, the two patients diagnosed by PCR had negative CSF culture results, and presented good evolution. PCR determination could allow a greater number of cases to be diagnosed earlier.

Epidemiology and treatment of the commonest form of listeriosis: meningitis and bacteraemia.

Listeria monocytogenes is a Gram-positive bacillus and facultative intracellular bacterium whose transmission occurs mainly through the consumption of contaminated food. Listeriosis has an incidence estimated at around three-six cases per million per year and the most common forms of the infection are neurolisteriosis, bacteraemia, and maternal-neonatal infection. Those affected by listeriosis are at the extremes age of the life or report specific risk factors, such as malignancies, causing a defect of cellular immunity. Patients with L. monocytogenes meningitis present with signs and symptoms similar to those reported in the general population with community-acquired bacterial meningitis, but can experience a longer prodromal phase. Instead, patients with bacteraemia present generally with a febrile illness without focal symptoms, or with influenza-like symptoms and diarrhoea. These aspecific findings make the diagnosis difficult in the population of patients at the highest risk such as cirrhotics or those receiving chemotherapy. Mortality rate is estimated around 20% with a significant increase among those reporting a delay in diagnosis and treatment and in those with severe comorbidity. A number of antibiotics have been demonstrated to be active against L. monocytogenes, but penicillin, amoxicillin, and ampicillin are those used with the highest frequency and suggested by current guidelines and expert opinions. These antibiotics bind to PBP-3 with high affinity and are stored in the cytosol when taken up by cells. Although amoxicillin appears to have a better activity than ampicillin on the basis of in vitro studies, ampicillin is currently the drug of choice for the treatment of listeriosis. Cotrimoxazole could be administered as an alternative treatment; its use is associated with a favourable outcome probably due to the favourable penetration with brain. Quinolones have an excellent tissue and cell penetration and are rapidly bactericidal, but their clinical activity is not as high as we can predict on the basis of experimental model. Linezolid offers a number of advantages in the empiric treatment of meningitis due to its favourable penetration of CSF and the absence of bacteriolytic effect on S. pneumoniae as confirmed by a number of case-series highlighting its use as rescue therapy of pneumococcal meningitis, but data are currently limited particularly if we consider neurolisteriosis. Combination therapies have been proposed to enhance the activity of penicillins against Listeria in an attempt to achieve complete killing and decrease mortality. Steroids use is ineffective.

Listeria monocytogenes meningitis in the Netherlands, 1985-2014: A nationwide surveillance study.

OBJECTIVES: Listeria monocytogenes can cause sepsis and meningitis. We report national surveillance data on L. monocytogenes meningitis in the Netherlands, describing incidence changes, genetic epidemiology and fatality rate. METHODS: We analyzed data from the Netherlands Reference Laboratory of Bacterial Meningitis for cases of L. monocytogenes meningitis. Strains were assessed by serotyping and bacterial population structure by multi-locus sequence typing. RESULTS: A total of 375 cases of Listeria meningitis were identified between 1985 and 2014. Peak incidence rates were observed in neonates (0.61 per 100,000 live births) and older adults (peak at 87 year; 0.53 cases per 100,000 population of the same age). Neonatal listerial meningitis decreased 17-fold from 1.95 per 100,000 live births between 1985 and 1989, to 0.11 per 100,000 live births between 2010 and 2014. Overall case fatality rate was 31%, in a multivariate analysis older age and concomitant bacteremia were associated with mortality (both p < 0.01). Clonal complexes (CC) CC1, CC2 and CC3 decreased over time from respectively 32% to 12%, 33% to 9% and 10% to 2% (all p < 0.001), while CC6 increased from 2% to 26% (p < 0.001). CONCLUSIONS: The incidence of neonatal listerial meningitis has declined over the past 25 years. The genotype CC6 has become the predominant genotype in listerial meningitis in the Netherlands. Mortality of listeria meningitis has remained high.