Invasive listeriosis in the Foodborne Diseases Active Surveillance Network (FoodNet), 2004-2009: further targeted prevention needed for higher-risk groups

Clinical Outcome and Factors with Dietary Behaviors in Pregnant Women with Listeria monocytogenes: A Hospital-Based Case-Control Study in Shanghai

Listeriosis is a globally rare foodborne disease that causes fetal-placental infection, leading to adverse pregnancy outcome, while limited research among pregnant women is available in China. This study was therefore aimed at analyzing the incidence, clinical manifestations, and clinical outcome of listeriosis among pregnant women and its associated dietary behavior risk factors in prevention. A hospital-based case-control study had been conducted from January 2017 to December 2021. Clinical data, laboratory information, and questionnaires including dietary behaviors and personal hygiene were collected within 2 days after case diagnosis. There were 48 pregnant women, including 12 cases and 36 controls, with an average age of 31.19 ± 3.75 years. The incidence of admission-based listeriosis among pregnant women was 1.6058 per 10,000. The 12 strains were divided into 3 serotypes: 1/2a(83.33%), 1/2b(8.33%), and 4b(8.33%). Among the cases, 5 cases (41.67%) resulted in abortion, 3 cases (25%) induced preterm labor, and 4 cases (33.33%) had full-term deliveries after treatment. There were 7 live births in the case group, among which 6 were admitted to the neonatal intensive care unit (NICU), while 1 case had a healthy fetal outcome. All patients in the control group gave birth to live fetuses. Epidemiological investigation revealed that pregnant women dining at restaurants three or more times per week might increase the risk of having Listeria infection. There were no significant differences in dietary consumed behaviors, hand hygiene, and refrigerator usage behaviors between case and control groups. The study suggested that dining at restaurants might be associated with Listeria infection among pregnant women. Therefore, it is essential to enhance education on listeriosis serious consequences and promote healthy dietary and hygiene habits among pregnant women.

Clinical significance of rapid detection and diagnosis of Listeria infection in blood with mass spectrometry

OBJECTIVE

Listeriosis is caused by the bacterium, Listeria monocytogenes, and is a significant health concern because of high hospitalization and mortality rates. This study reports seven cases of pregnancy-associated listeriosis diagnosed with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry performed on infection-positive blood culture.

METHODS

Blood culture-positive samples of seven patients whose pregnancy was complicated by Listeria infection and treated at Xuanwu Hospital of Capital Medical University between January 2016 and December 2021 were analyzed retrospectively. Strains identified by MALDI-TOF mass spectrometry were compared with colony identification results. Identification accuracy and consistency were assessed.

RESULTS

A total of seven strains of Listeria were collected from seven pregnant women presented with fever (37.6-39.9°C). Clinical abnormalities included abnormal liver function, emaciation, hypoalbuminemia, hypocalcemia, hypokalemia, hyponatremia, ketosis, mild to moderate anemia, leukopenia, and thrombocytopenia. Compared with the traditional culture method, MALDI-TOF mass spectrometry led to much earlier identification (4-6 h vs. 3-4 days) with 100% identification accuracy. Of the seven pregnancies complicated by Listeria, only two led to live births. Of the five fetal deaths, three occurred in the second trimester.

CONCLUSION

In this series of pregnancy-associated listeriosis cases, the fetal mortality rate was 71%. MALDI-TOF mass spectrometry is a valuable method that can identify Listeria from blood culture rapidly and accurately.

Microbial anti-biofilms: types and mechanism of action

Biofilms have been recognized as a serious threat to public health as it protects microbes from antimicrobials, immune defence mechanisms, chemical treatments and nutritional stress. Biofilms are also a source of concern in industries and water treatment because their presence compromises the integrity of equipment. To overcome these problems, it is necessary to identify novel anti-biofilm compounds. Products of microorganisms have been identified as promising broad-spectrum anti-biofilm agents. These natural products include biosurfactants, antimicrobial peptides, enzymes and bioactive compounds. Anti-biofilm products of microbial origin are chemically diverse and possess a broad spectrum of activities against biofilms. The objective of this review is to give an overview of the different types of microbial anti-biofilm products and their mechanisms of action.

Unlocking the Hidden Threat: Impacts of Surface Defects on the Efficacy of Sanitizers Against Listeria monocytogenes Biofilms on Food-contact Surfaces in Tree Fruit Packing Facilities

Food-contact surfaces showing signs of wear pose a substantial risk of Listeria monocytogenes contamination and may serve as persistent sources of cross-contamination in fresh produce packinghouses. This study offers a comprehensive exploration into the influence of surface defects on the efficacies of commonly used sanitizers against L. monocytogenes biofilms on major food-contact surfaces. The 7-day-old L. monocytogenes biofilms were cultivated on food-contact surfaces, including stainless steel, polyvinyl chloride, polyester, low-density polyethylene, and rubber, with and without defects and organic matter. Biofilms on those surfaces were subjected to treatments of 200 ppm chlorine, 400 ppm quaternary ammonium compound (QAC), or 160 ppm peroxyacetic acid (PAA). Results showed that surface defects significantly (P < 0.05) increased the population of L. monocytogenes in biofilms on non-stainless steel surfaces and compromised the efficacies of sanitizers against L. monocytogenes biofilms across various surface types. A 5-min treatment of 200 ppm chlorine caused 1.84-3.39 log10 CFU/coupon reductions of L. monocytogenes on worn surfaces, compared to 2.79-3.93 log10 CFU/coupon reduction observed on new surfaces. Similarly, a 5-min treatment with 400 ppm QAC caused 2.05-2.88 log10 CFU/coupon reductions on worn surfaces, compared to 2.51-3.66 log10 CFU/coupon reductions on new surfaces. Interestingly, PAA sanitization (160 ppm, 1 min) exhibited less susceptibility to surface defects, leading to 3.41-4.35 log10 CFU/coupon reductions on worn surfaces, in contrast to 3.68-4.64 log10 CFU/coupon reductions on new surfaces. Furthermore, apple juice soiling diminished the efficacy of sanitizers against L. monocytogenes biofilms on worn surfaces (P < 0.05). These findings underscore the critical importance of diligent equipment maintenance and thorough cleaning processes to effectively eliminate L. monocytogenes contamination on food-contact surfaces.

[Listeria meningoencephalitis resulting in complete bilateral ophtalmoplegia and locked-in syndrome]

This is a description of the case of quite severe neurolisteriosis in an adult man resulting in the rare combination of neurological symptoms such as complete bilateral ophtalmoplegia and locked-in syndrome. The case illustrates clinical features that are special for this disorder and also highlights management of such patients.

Long-term neurological and neurodevelopmental outcome of neonatal listeriosis in France: a prospective, matched, observational cohort study

BACKGROUND

Maternal-neonatal listeriosis is a rare and serious infection. The long-term outcome of surviving infants with early-onset or late-onset listeriosis remains unknown. We aimed to determine the long-term neurological and neurodevelopmental outcome of neonatal listeriosis.

METHODS

In this prospective, matched, observational cohort study, we evaluated children born with microbiologically confirmed maternal-neonatal listeriosis in the French MONALISA cohort. At age 5 years, children underwent neurological and neurodevelopmental assessments of sensory deficits, executive function, adaptive behaviour, and cognitive and motor coordination function. The cognitive domain was assessed using the French version of the Wechsler Preschool and Primary Scale of Intelligence, fourth edition, and scored by Full Scale Intelligence Quotient (FSIQ). The motor domain was assessed by physical examination designed to screen for cerebral palsy and developmental coordination disorder. Executive functioning was assessed using the statue and inhibition subtests of Neuropsychological Assessment, second version. The sensory domain was assessed by parental interview, medical report, and clinical assessment. Adaptive behaviour was measured using the Vineland-II behaviour scale from parent-reported assessments of functional communication, socialisation, daily living, and motor skills. Results were compared with gestational age-matched children from two national prospective cohorts: EPIPAGE-2 (preterm infants) and ELFE (term infants from a general population of infants >32 weeks gestation). This study is registered with ClinicalTrials.gov (NCT02580812).

FINDINGS

Of 59 children who were alive and eligible to participate in the study, 53 (median age 5 years, IQR 5-6) were enrolled for neurodevelopmental assessments between Oct 26, 2016, and Oct 29, 2019. Of 53 children, 31 (58%) had been born preterm, 22 (42%) had early-onset systemic infection, 18 (34%) had early-onset non-systemic infection, and six (11%) had late-onset systemic infection, all with meningitis. 29 (66%) of 44 children, in whom neurodevelopmental disabilities scores were available, developed at least one disability; eight (18%) children had severe neurodevelopmental disabilities. Of four children with late-onset infection and in whom neurodevelopmental disabilities scores were available, three developed at least one neurodevelopmental disability. Neurological and neurodevelopmental outcomes of children with neonatal listeriosis did not differ from those of gestational age-matched control children without infection (relative risk [RR] of at least one disability 0·99 [95% CI 0·65-1·51; p=0·97]; RR of FSIQ less than -1 SD 0·92 [0·54-1·54; p=0·74]).

INTERPRETATION

These results highlight the burden of persistent disability and dominant contribution of prematurity to long-term outcomes in children born with neonatal listeriosis. The findings support the implementation of systematic long-term screening and provision of tailored education and special needs support.

FUNDING

Institut Pasteur, Inserm, French Public Health Agency, Contrat de Recherche Clinique, and Assistance Publique-Hôpitaux de Paris.

[A case of community-acquired Listeria monocytogenes meningitis]

Meningitis caused by Listeria monocytogenes is a rare disease in immunocompetent individuals, however, in the presence of certain risk factors with clinical signs indicating infection of the central nervous system it should not be ignored. In this case report, we present the medical history of a 72-year-old man, suffering from hypertension and liver cirrhosis, who was diagnosed with meningitis caused by L. monocytogenes. The patient was admitted to our Department with the symptoms of weakness, dizziness, high fever and urinary incontinence. Laboratory tests showed elevated inflammatory and liver enzyme values as well as low white blood cell and platelet counts were confirmed. Imaging tests did not prove any abnormalities. Due to septic parameters, after microbiological samples were collected, empiric ceftriaxon and metronidazol treatment was started. Despite our therapeutic efforts, the condition of the patient had not improved significantly. The patient still suffered from high fever; increasing agitation and tremor, coordination disorder appeared, raising the possibility of a bacterial infection of the central nervous system. Examination of the cerebrospinal fluid confirmed the diagnosis of bacterial meningitis. In the meantime, findings of microbiological cultures verified the infection of L. monocytogenes, however, cerebrospinal fluid culture did not detect any pathogen. Following that, the therapy continued with targeted ampicillin which resulted in rapid improvement of the patient's condition; fevers and neurological symptoms have ceased to exist. We considered the case worthy of presentation because of the pitfalls of the diagnosis, the emerging differential diagnostic difficulties and the favorable outcome due to the effectiveness of targeted antibiotic treatment. Orv Hetil. 2023; 164(36): 1437-1441.

Human Listeriosis

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that can cause severe invasive infections upon ingestion with contaminated food. Clinically, listerial disease, or listeriosis, most often presents as bacteremia, meningitis or meningoencephalitis, and pregnancy-associated infections manifesting as miscarriage or neonatal sepsis. Invasive listeriosis is life-threatening and a main cause of foodborne illness leading to hospital admissions in Western countries. Sources of contamination can be identified through international surveillance systems for foodborne bacteria and strains' genetic data sharing. Large-scale whole genome studies have increased our knowledge on the diversity and evolution of L. monocytogenes, while recent pathophysiological investigations have improved our mechanistic understanding of listeriosis. In this article, we present an overview of human listeriosis with particular focus on relevant features of the causative bacterium, epidemiology, risk groups, pathogenesis, clinical manifestations, and treatment and prevention.

Listeriosis Risk Model for Cancer Patients Who Consume Ready-to-Eat Salad

The foodborne pathogen Listeria monocytogenes generally infects immunocompromised individuals, such as cancer patients, more frequently and with higher morbidity and mortality than the general population. Because of the anticipated risk associated with L. monocytogenes and other pathogens in produce, immunocompromised individuals are often placed on neutropenic diets that exclude fresh produce, though these risks have not been quantified. Therefore, this study developed a data-driven risk model for listeriosis in cancer patients who consume ready-to-eat (RTE) salads, consisting of leafy greens, cucumbers, and tomatoes, as influenced by kitchen-scale treatments and storage practices. Monte Carlo simulations were used to model the risk of invasive listeriosis during one chemotherapy cycle. Refrigerating all salad components decreased median risk by approximately one-half log. For refrigerated salads with no treatment, the predicted median risk was ≤ 4.3 × 10^-08. When salad ingredients were surface blanched with greens rinsed, the predicted risk decreased to 5.4 × 10^-10. Predicted risk was lowest (1.4 × 10^-13) for a blanched "salad" consisting of solely cucumbers and tomatoes. Interestingly, rinsing, as recommended by FDA only decreased median risk by 1 log. A sensitivity analysis revealed that the highly variable dose-response parameter k strongly influenced risk, indicating that reducing uncertainty in this variable may improve model accuracy. Overall, this study demonstrates that kitchen-scale pathogen reduction approaches have high risk-reduction efficacy and could be considered as an alternative to diets that exclude produce when making risk management decisions.

Food safety knowledge attitude and practices of oncology nurses, in Lebanese hospitals

Background

Cancer patients undergoing chemotherapy treatment, have a higher risk to foodborne infections as compared to other populations. Oncology nurses, having a direct significant contact with these patients, could be the first information source concerning food safety and play a pivotal role in reducing these risks.

Objective

This study aims to assess the level of knowledge regarding food safety among oncology nurses, as well as their attitudes and practices in private hospitals in Lebanon.

Methods

A self-administered questionnaire was filled by Oncology nurses (n = 134) working in eighteen private hospitals in Lebanon located in Mount Lebanon (n = 11) and Beirut (n = 7).

Results

Overall, oncology nurses scored 76%, 95%, 86.9% and 83.4% on the knowledge, attitude, and practices questions, and overall composite knowledge, attitude, practices (KAP) score, respectively. Knowledge scores were higher among nurses holding a graduate degree (mean = 85; p < 0.05), and those who attended a training course (mean = 79; p < 0.05). Attitude scores of nurses who read brochures were higher (p < 0.001). Attending conferences on food safety showed statistically significant effect on better practice scores (p < 0.001).

Conclusion

Accordingly, the findings highlight the need to develop standardized food safety curriculum and training necessary to allow oncology nurses to contribute to the education of cancer patients and decrease their risk of foodborne infection.

Listeria meningitis associated with tonsillar herniation in an immunocompetent school-aged child

Listeria monocytogenes can cause severe illnesses such as gastroenteritis, sepsis and neurolisteriosis, especially in infants, the elderly and immunocompromised patients. We report a case of a previously healthy school-aged girl presenting with severe neurological deficits found to have Listeria meningoencephalitis. Her potential exposure to L. monocytogenes was consumption of contaminated cheese. She had some clinical improvement after initiation of tailored Listeria anti-microbial coverage with ampicillin and gentamicin; however, she developed hydrocephalus requiring external ventricular drain placement and tonsillar herniation requiring emergent posterior fossa decompression. The patient made significant improvements after neurosurgical intervention, and along with continued antibiotics and subsequent rehabilitation services, she improved to near full recovery within a year. The case highlights that neurolisteriosis can affect even immunocompetent children, and aggressive neurosurgical interventions should be considered in patients who develop severe complications such as hydrocephalus and tonsillar herniation to improve outcomes.

Analysis of Clinical and Microbiological Features of Listeria monocytogenes Infection

Introduction

To analyze the demographics and clinical features of 59 cases of Listeria monocytogenes, and determine the predisposing conditions for severe meningitis infections for reference.

Materials and methods

A total of 59 cases isolated L. monocytogenes from 2009 to 2020 were enrolled. Electronic medical record data were used to determine the epidemiological and clinical characteristics of L. monocytogenes infection. Univariate and multifactorial logistic regression analyses were performed to predict risk factors for Listeria meningitis.

Results

A total of 59 cases (median age of 52 years, 30 females and 29 males) were enrolled. Twenty-five patients (42.37%) developed a neuroinvasive infection. The indexes of interleukin-6 (IL-6), CD3+T, CD4+T, and CD8+T cells in the study group were higher than those in the control group (P<0.05). In univariate analysis, the use of hormone drugs (odds ratio=3.21, P=0.000) and immunosuppressive agents (odds ratio=3.06, P=0.000) were relevant predictors of severe meningitis. 47 patients (79.66%) were treated with ampicillin (27.12%), carbapenems (18.64%), quinolones (11.86%), and β-lactamase inhibitors (11.86%) as the primary agents of antimicrobial therapy. Thirty-four patients (57.63%) showed clinical improvement, five patients (8.47%) had a poor prognosis, and two patients (3.39%) died.

Conclusion

Infection with Listeria changed the levels of IL-6, CD3+T, CD4+T, and CD8+T cells, and these analyzing items were significantly different between L. monocytogenes and other bacterial infections. Long-term use of immunosuppressants and hormones may be risk factors for severe adult forms of Listeria-related infections. Sensitive antibiotics, such as penicillins and carbapenems, should be added or replaced in the early empiric treatment of L. monocytogenes.

Mouse models for bacterial enteropathogen infections: insights into the role of colonization resistance

Globally, enteropathogenic bacteria are a major cause of morbidity and mortality.1-3 Campylobacter, Salmonella, Shiga-toxin-producing Escherichia coli, and Listeria are among the top five most commonly reported zoonotic pathogens in the European Union.4 However, not all individuals naturally exposed to enteropathogens go on to develop disease. This protection is attributable to colonization resistance (CR) conferred by the gut microbiota, as well as an array of physical, chemical, and immunological barriers that limit infection. Despite their importance for human health, a detailed understanding of gastrointestinal barriers to infection is lacking, and further research is required to investigate the mechanisms that underpin inter-individual differences in resistance to gastrointestinal infection. Here, we discuss the current mouse models available to study infections by non-typhoidal Salmonella strains, Citrobacter rodentium (as a model for enteropathogenic and enterohemorrhagic E. coli), Listeria monocytogenes, and Campylobacter jejuni. Clostridioides difficile is included as another important cause of enteric disease in which resistance is dependent upon CR. We outline which parameters of human infection are recapitulated in these mouse models, including the impact of CR, disease pathology, disease progression, and mucosal immune response. This will showcase common virulence strategies, highlight mechanistic differences, and help researchers from microbiology, infectiology, microbiome research, and mucosal immunology to select the optimal mouse model.

Perinatal Infection with Listeria monocytogenes: A 10-Year Hospital-Based Study in Western China

Objective

Listeriosis is a rare but severe foodborne disease that is contracted by the consumption of food contaminated with Listeria, and perinatal listeriosis can cause major adverse pregnancy outcomes. In the current study, we sought to retrospectively analyze 10 years of perinatal outcomes due to listeriosis in western China.

Methods

Based on the isolation of Listeria monocytogenes (L. monocytogenes), we retrospectively reviewed the pregnancy-associated cases of listeriosis from June 2010 to February 2022 at our hospital. We investigated the crude incidence, clinical manifestations, perinatal management, and outcomes of perinatal listeriosis cases.

Results

We diagnosed a total of 28 cases of perinatal listeriosis during the study period at our hospital, including four cases of twin pregnancies. Of the 28 cases, 32.14% (9/28) were infected in the second trimester and 67.86% (19/28) in the third trimester. The fetal or neonatal mortality rate for perinatal listeriosis was high, with a crude fetal mortality rate of 46.88% (15/32) in the 32 offspring and a neonatal mortality rate of 47.06% (8/17) in the 17 live births.

Conclusion

Perinatal listeriosis exhibits high fetal or neonatal mortality. We recommend that appropriate antibiotics be administered in cases of perinatal listeriosis.

Maternal Infection with Listeria monocytogenes in Twin Pregnancy

Listeria monocytogenes is the conditional pathogenic bacteria, and pregnant women are at higher risk of infection due to depressed immunity. Infection with Listeria monocytogenes in twin pregnancy is rare but devastating, which puts forwards a great challenge for clinical management. Here, a 24-year-old woman was diagnosed with twin pregnancy, intrauterine death of one fetus and fever at 29⁺⁴ week of gestation. Two days later, she developed into pericardial effusion, pneumonedema and potential septic shock. The emergent cesarean delivery was performed after anti-shock treatment. One alive and another dead fetus were delivered. Then, she developed postpartum hemorrhage after the surgery. Urgent exploratory laparotomy was conducted at the sites of cesarean section and B-Lynch suture to stop bleeding. The culture of blood and maternal side of both placentas indicated Listeria monocytogenes. Following anti-infection therapy with ampicillin-sulbactam, she recovered well and discharged with negative result of blood bacterial culture and normal inflammatory indicators. The patient was hospitalized for a total of 18 days including 2 days in the intensive care unit (ICU), and the anti-infection treatment was conducted throughout the course. Symptoms of the Listeria monocytogenes infection in pregnancy are non-specific, which should be paid more attention in case of unexplained fever and fetal distress. The blood culture is effective for accurate diagnosis. Listeria monocytogenes infection is associated with poor pregnancy outcomes. Close monitoring of fetal condition, early intervention with antibiotics, timely termination of pregnancy and comprehensive management of complications are essential for better prognosis.

Immune-metabolic adaptations in pregnancy: A potential stepping-stone to sepsis

Physiological shifts during pregnancy predispose women to a higher risk of developing sepsis resulting from a maladapted host-response to infection. Insightful studies have delineated subtle point-changes to the immune system during pregnancy. Here, we present an overlay of these point-changes, asking what changes and when, at a physiological, cellular, and molecular systems-level in the context of sepsis. We identify distinct immune phases in pregnancy delineated by placental hormone-driven changes in homeostasis setpoints of the immune and metabolic systems that subtly mirrors changes observed in sepsis. We propose that pregnancy immune-metabolic setpoint changes impact feedback thresholds that increase risk for a maladapted host-response to infection and thus act as a stepping-stone to sepsis. Defining maternal immune-metabolic setpoint changes is not only vital for tailoring the right diagnostic tools for early management of maternal sepsis but will facilitate an unravelling of the pathophysiological pathways that predispose an individual to sepsis.

Antibacterial Capability of MXene (Ti3C2Tx) to Produce PLA Active Contact Surfaces for Food Packaging Applications

The globalization of the market and the increase of the global population that requires a higher demand of food products superimposes a big challenge to ensure food safety. In this sense, a common strategy to extend the shelf life and save life of food products is by avoiding bacterial contamination. For this, the development of antibacterial contact surfaces is an urgent need to fulfil the above-mentioned strategy. In this work, the role of MXene (Ti₃C₂T_x) in providing antibacterial contact surfaces was studied through the creation of composite films from polylactic acid (PLA), as the chosen polymeric matrix. The developed PLA/MXene films maintained the thermal and mechanical properties of PLA and also presented the attractive antibacterial properties of MXene. The composites' behaviour against two representative foodborne bacteria was studied: Listeria mono-cytogenes and Salmonella enterica (representing Gram-positive and Gram-negative bacteria, respectively). The composites prevented bacterial growth, and in the case of Listeria only 0.5 wt.% of MXene was necessary to reach 99.9999% bactericidal activity (six log reductions), while against Salmonella, 5 wt.% was necessary to achieve 99.999% bactericidal activity (five log reductions). Cy-totoxicity tests with fHDF/TER166 cell line showed that none of the obtained materials were cytotoxic. These results make MXene particles promising candidates for their use as additives into a polymeric matrix, useful to fabricate antibacterial contact surfaces that could prove useful for the food packaging industry.

Complications Associated with Foodborne Listeriosis: A Scoping Review

Listeria monocytogenes is a relatively rare but highly pathogenic bacterium that can cause foodborne infections. In the United States there are ∼1600 cases per year, 94% of which result in hospitalizations and 20% in deaths. Per-case burden is high because the disease also causes serious complications, including sepsis, encephalitis, meningitis, miscarriage, and stillbirth. The disease burden of L. monocytogenes is underestimated because some of these acute complications can also result in long-term outcomes. In this article, we conducted a scoping review of L. monocytogenes complications and longer term outcomes from articles published between 2000 and 2018. Search terms were developed for four major databases (PubMed, Scopus, Web of Science, and Embase) as well as gray literature and hand searches of review articles. We follow standard scoping review methodology and assessment. Out of 10,618 unique articles originally identified, 115 articles were included, representing 49 unique outcomes. The majority of studies were cohort designs (n = 67) and conducted in the United States or Europe (n = 98). Four major outcome groupings were death, neurological disorders, sepsis, and congenital infection. This study identifies substantial research on the common acute complications of L. monocytogenes and few long-term consequences of L. monocytogenes. We identify the need for additional studies to determine the longer term impacts of these acute complications.

Rhombencephalitis in Pregnancy-A Challenging Case of Probable Listeria Infection

Rhombencephalitis refers to inflammation of the brainstem and cerebellum, and can be caused by infections, autoimmune disorders or paraneoplastic syndromes. The most common infective cause is the bacterium Listeria monocytogenes. Listeria monocytogenes is the predominant species to cause human listeriosis, and is commonly due to the ingestion of contaminated foods. Symptoms include a mild gastroenteritis, fever (often with extreme temperature variations), headache, and myalgia. In more severe cases, invasive disease may lead to bacteraemia and neurolisteriosis. Pregnant women are more susceptible to listeriosis, which is believed to be due to pregnancy-related immune modulation. Maternal-neonatal infection with adverse pregnancy outcomes include neonatal listeriosis, spontaneous miscarriage and intrauterine fetal demise. Diagnosis may be challenging due to initial nonspecific symptoms and low sensitivity and specificity of confirmatory diagnostic laboratory tests. Here, we describe a case of rhombencephalitis in pregnancy, attributed to Listeria, and review the clinical features, diagnosis and multidisciplinary management. Lastly, we describe the immunological response to Listeria monocytogenes and show in vitro pro-inflammatory effects of Listeria monocytogenes on peripheral blood mononuclear cells and placental explants.

Maternal sepsis caused by Listeria monocytogenes with a fatal fetal outcome

Improving maternal and child health is a global priority. Although infection with Listeria monocytogenes (LM), a small facultative anaerobic, gram-positive motile bacillus is rare, when it infects the maternal-fetoplacental unit, it can result in adverse fetal sequelae such as chorioamnionitis, preterm labour, neonatal sepsis, meningitis and neonatal death. Pregnancy-associated listeriosis may present with a plethora of diverse, non-specific symptoms such as fever, influenza-like or gastrointestinal symptoms, premature contractions and preterm labour. It has a predilection for the second and third trimester of pregnancy, occurring sporadically or as part of an outbreak, most of which have involved unpasteurised dairy products, long shelf life products, contaminated ready-to-eat food, deli meats and soft cheeses. Strains belonging to the clonal complexes 1, 4 and 6 are hypervigilant and are commonly associated with maternal-neonatal infections. Maternal listeriosis occurs as a direct consequence of LM-specific placental tropism, which is mediated by the conjugated action of internalin A and internalin B at the placental barrier. The diagnosis is established from placental culture. Penicillin, ampicillin and amoxicillin are the antimicrobials of choice. It has a high fetal morbidity of up to 30%. The authors present the case of a multiparous woman in her early 20s presenting with sepsis and preterm premature rupture of her membranes at 21 weeks gestation. A live baby was delivered spontaneously and died shortly after birth. Placental cultures and postmortem examination were consistent with the diagnosis of disseminated Listeria infection. Due to the increased susceptibility of pregnant women for LM, a high index of clinical suspicion is required to establish the diagnosis and initiate appropriate antimicrobial therapy to reduce adverse fetal outcomes.

LmTraceMap: A Listeria monocytogenes fast-tracing platform for global surveillance

Listeria monocytogenes can cause listeriosis, and people with hypoimmunity such as pregnant women, infants and fetuses are at high risk of invasive infection. Although the incidence of listeriosis is low, the fatality rate is high. Therefore, continual surveillance and rapid epidemiological investigation are crucial for addressing L. monocytogenes. Because of the popularity of next-generation sequencing, obtaining the whole-genome sequence of a bacterium is easy. Several genome-based typing methods are available, and core-genome multilocus sequence typing (cgMLST) is the most recognized methods. Using cgMLST typing to compare L. monocytogenes whole-genome sequences (WGS) with those obtained across distinct regions is beneficial. However, the concern is how to incorporate the powerful cgMLST method into investigations, such as by using source tracing. Herein, we present an easy-to-use web service called–LmTraceMap (http://lmtracemap.cgu.edu.tw/hua_map/test/upload.php; http://120.126.17.192/hua_map/test/upload.php) that can help public-health professionals rapidly trace closely related isolates worldwide and visually inspect them in search results on a world map with labeled epidemiological data. We expect the proposed service to improve the convenience of public health investigations.

Listeriosis during pregnancy: a retrospective cohort study

Background

Pregnancy-associated listeriosis is a severe infectious disease and potentially leads to fetal/neonatal fatal, while limited information on pregnancy-associated listeriosis is available in China. This study aimed to reveal the clinical characteristics and outcomes of pregnancy-associated listeriosis cases and provide references for treating and managing this disease.

Methods

We performed a retrospective study on maternal and neonatal patients with pregnancy-associated listeriosis. The clinical characteristics of pregnancy-associated listeriosis were studied, and the outcome determinants of neonatal listeriosis were explored.

Results

14 cases of pregnancy-associated listeriosis were identified. The incidence of pregnancy-associated listeriosis in our hospital was 16.69/100,000 births. All of the 14 maternal patients eventually recovered after delivery shortly with no sequelae. None of the 12 mothers who delivered in this hospital received antepartum first-line empirical treatment. Among the 14 neonatal cases, 1 was late-onset listeriosis and 13 were early-onset cases; 11 survived and 3 died. Fatality rates were significantly higher in outborn neonates (P = 0.005). Besides, higher mortality rates were observed in neonates with lower birth weight (P = 0.038), gestational age < 28 weeks (P = 0.056), and Apgar score (5th min) < 5 (P = 0.056), with marginally significant differences.

Conclusions

Pregnancy-associated listeriosis would bring disastrous effects to the neonatal cases, especially to the outborn, low birth weight, and low gestational age of neonates. Timely detection and treatment should be taken seriously for the key neonates. How to early detect L. monocytogenes infected cases, especially in the prenatal stage, remains a serious challenge.

Saudi Arabia Household Awareness and Knowledge of Food Safety

Food safety is a critical problem that impacts everyone worldwide. Many countries around the world are becoming increasingly reliant on the availability and safety of their food supply. Despite growing public consciousness about food-related dangers, the growth in food poisoning cases implies that individuals continue to make food consumption, food storage, and food preparation decisions that are less than optimal from a health and safety standpoint. The aim of this study was to assess Saudi Arabia’s households’ knowledge and practices of food safety. A cross-sectional study was conducted to assess knowledge of food safety and practices among a group of households in Saudi Arabia. An online questionnaire using social media (Facebook, Twitter, Instagram, and WhatsApp), and emails communications were distributed. A total of 309 adults (age range 18–59 years) participated in the study. In general, there were no differences between regions regarding the knowledge of food safety. Additionally, most of the participants had good practices of food safety. The findings of our study show that the gender, age, and educational level are factors that have an impact on the knowledge of food safety among respondents. Regarding food safety practices, in general, the results show that the participants had good practices. Therefore, organizations should focus on educational programs, training, holding workshops and activities in public places such as malls, schools, and home visit to improve and increases food safety knowledge and practices.

Listerial Spontaneous Bacterial Peritonitis

Spontaneous bacterial peritonitis (SBP) is a severe complication of ascites often seen in advanced hepatic disease that is most commonly caused by Gram-negative bacilli. Here, we report a rare case of Listeria monocytogenes SBP, diagnosed by peritoneal fluid culture and responsive to ampicillin, in a patient with portal hypertension secondary to nodular regenerative hyperplasia. Because Listeria species are resistant to empiric SBP therapies and delays in treatment have been associated with increased mortality, they must be considered in high-risk patients.

Assessing Existing Food Safety Resources with United Kingdom-Based Chemotherapy Patients and Family Caregivers for Future Learning Purposes

ABSTRACT

Because the incidence of foodborne infection is more prevalent among cancer patients and the domestic kitchen is a contributor to foodborne infection, appropriate domestic food safety practices are needed to safeguard this at-risk population. Although patients are aware of the increased risk of infection, previous self-reported data indicate potential food safety malpractices among patients and family caregivers, thus suggesting the need for targeted food safety information. However, existing United Kingdom resources provide inconsistent and insufficient food safety information. Involvement of intended end users in the cocreation of interventions increases potential effectiveness. Qualitative data were collated from in-depth interviews and a focus group with United Kingdom chemotherapy patients and family caregivers (n = 35) to determine perceptions and preferences for food safety information by evaluating existing food safety resources from international providers (n = 12). Although participants liked digital interventions (e.g., Web sites and videos), traditional paper-based leaflets were perceived as the most beneficial because they could be referred to on repeated occasions. Despite the drawbacks associated with some resources, combining approaches in a multiresource intervention was favored by patients and family caregivers. Ensuring patients are not overwhelmed with excessive information was important. Short, logical, engaging, educational, and entertaining information to evoke an interest in the topic was preferred. Utilization of graphics to supplement descriptive information may enhance comprehensibility. Interventions need to be appropriate for patients and caregivers, and delivery by trusted health care professionals may enhance the credibility of the message. Preferred approaches to facilitate targeted food safety communication were identified, and these findings can be utilized to cocreate targeted food safety interventions for chemotherapy patients and family caregivers.

HIGHLIGHTS

Genetic Diversity of Listeria monocytogenes Isolated From Three Commercial Tree Fruit Packinghouses and Evidence of Persistent and Transient Contamination

Whole genome analysis was performed on 501 isolates obtained from a previous survey which recovered 139 positive environmental sponge samples (i.e., up to 4 isolates per sample) from a total of 719 samples collected at 40 standardized sites in 3 commercial apple packinghouse facilities (i.e., P1, P2, and P3) over 3 successive seasons in a single production year. After excluding duplicated isolates, the data from 156 isolates revealed the clonal diversity of L. monocytogenes and allowed the detection of transient contamination, persistent contamination, and cross-area transmission events. Facility P2 with the poorest sanitary conditions had the least diversity (Shannon's index of 0.38). P2 contained a Clonal Complex (CC) 554, serogroup IVb-v1 strain that persisted throughout the year and spread across the entire facility, a singleton Sequence Type (ST) 1003, lineage III strain that persisted through two seasons and spread across two areas of the facility, and 3 other clones from transient contaminations. P1 and P3, facilities with better sanitary conditions, had much higher diversity (i.e., 15 clones with a Shannon's index of 2.49 and 10 clones with a Shannon's index of 2.10, respectively) that were the result of transient contamination. Facilities P1 and P3 had the highest incidence (43.1%) of lineage III isolates, followed by lineage I (31.3%) and lineage II (25.5%) isolates. Only 1 isolate in the three facilities contained a premature stop codon in virulence gene inlA. Fourteen samples yielded 2-3 clones per sample, demonstrating the importance of choosing appropriate methodologies and selecting a sufficient number of isolates per sample for studying L. monocytogenes diversity. Only 1 isolate, belonging to CC5 and from facility P3, contained a known plasmid, and this was also the only isolate containing benzalkonium chloride tolerance genes. The persistent CC554 strain did not exhibit stronger sanitizer resistance than other isolates and did not contain any confirmed molecular determinants of L. monocytogenes stress resistance that were differentially present in other isolates, such as genes involved in sanitizer tolerance, heavy metal resistance, biofilm-forming, stress survival islet 1 (SSI-1), stress survival islet 2 (SSI-2) or Listeria genomic island (LGI2).

Septicemia Due to Listeria monocytogenes Infection: A Systematic Review and Meta-Analysis

Listeriosis is a rare bacterial infection associated with foodborne illness that can result in septicemia, a serious acute outcome. Sepsis is responsible for one in three deaths during hospitalization. The objective of this study was to conduct a systematic review and meta-analysis to estimate the proportion of Listeria monocytogenes infections resulting in septicemia. PubMed, Embase, Scopus, and Web of Science were searched from January 1, 2000, to April 1, 2018, for epidemiological studies that assessed studies focusing on L. monocytogenes infections with the outcome of septicemia. Articles in English, Spanish, and Portuguese using case-control, cohort, or outbreak studies reporting measures of association between L. monocytogenes and septicemia were included. Bias and heterogeneity were assessed using univariate meta-regression for region, sample size, study design, and report method. Nineteen articles were eligible for inclusion post-screening, the majority of which were conducted in Europe (n = 15); utilized a retrospective cohort design (n = 16); and collected data via routine or laboratory surveillance methods (n = 10). Prevalence of sepsis ranged from 4.2% to 100% among study populations of 6 to 1374 individuals. Overall, the proportion of listeriosis cases that developed sepsis was 46% (95% confidence interval [CI] 31.0-61.0%); for neonatal cases, 21.3% (95% CI 11.0-31.6%); and for maternal and neonatal cases, 18.8% (95% CI 10.7-26.8%). The heterogeneity was high for overall and group meta-analyses, but it could not be explained by the subanalyses for the overall proportion, whereas for neonatal, and neonatal and maternal cases combined, China had a significantly lower proportion than Europe and the United States. Septicemia following L. monocytogenes infection is a severe acute complication with 31-61% rate found overall; however, greater delineation of demographic data is needed to determine important risk factors. Future research should aim to address the gaps in knowledge in the long-term outcomes of sepsis from L. monocytogenes infection, and whether these outcomes differ from those due to other infections.

Pathogenicity and virulence of Listeria monocytogenes: A trip from environmental to medical microbiology

Listeria monocytogenes is a saprophytic gram-positive bacterium, and an opportunistic foodborne pathogen that can produce listeriosis in humans and animals. It has evolved an exceptional ability to adapt to stress conditions encountered in different environments, resulting in a ubiquitous distribution. Because some food preservation methods and disinfection protocols in food-processing environments cannot efficiently prevent contaminations, L. monocytogenes constitutes a threat to human health and a challenge to food safety. In the host, Listeria colonizes the gastrointestinal tract, crosses the intestinal barrier, and disseminates through the blood to target organs. In immunocompromised individuals, the elderly, and pregnant women, the pathogen can cross the blood-brain and placental barriers, leading to neurolisteriosis and materno-fetal listeriosis. Molecular and cell biology studies of infection have proven L. monocytogenes to be a versatile pathogen that deploys unique strategies to invade different cell types, survive and move inside the eukaryotic host cell, and spread from cell to cell. Here, we present the multifaceted Listeria life cycle from a comprehensive perspective. We discuss genetic features of pathogenic Listeria species, analyze factors involved in food contamination, and review bacterial strategies to tolerate stresses encountered both during food processing and along the host's gastrointestinal tract. Then we dissect host-pathogen interactions underlying listerial pathogenesis in mammals from a cell biology and systemic point of view. Finally, we summarize the epidemiology, pathophysiology, and clinical features of listeriosis in humans and animals. This work aims to gather information from different fields crucial for a comprehensive understanding of the pathogenesis of L. monocytogenes.

Food Safety Knowledge and Practices of Pregnant Women and Postpartum Mothers in Slovenia

Food safety during pregnancy and postpartum is important for preventing foodborne diseases, while pregnant women are considered vulnerable due to their immunomodulatory condition. The current study aimed to investigate the self-reported food safety knowledge and practices of pregnant women and postpartum mothers in Slovenia using an online questionnaire and to compare the results with nonpregnant women as a control group. The study was conducted with 426 women, of whom 145 were pregnant, 191 were not pregnant, and 90 were postpartum. The online questionnaire consisted of questions related to food safety risk perception, hand hygiene, food purchase, food storage, food preparation and handling of infant formula and breast milk. The results showed that women generally have basic knowledge of proper food handling and are aware of food safety, but some specific gaps were identified in food handling at home, especially concerning microbiological risks. However, the results showed that pregnant women performed better than the postpartum group, and both groups performed significantly better than the nonpregnant group. The media was most frequently cited as a source of food safety information, especially by the pregnant group. Trained health workers should also inform women on how to ensure food safety in the home environment.

Evaluation of Avocados as a Possible Source of Listeria monocytogenes Infections, United States, 2016 to 2019

ABSTRACT

Outbreaks of Listeria monocytogenes infections have historically been associated with contaminated deli meats, but recent outbreaks have been linked to produce. To date, avocados have not been identified as the source of any outbreaks of L. monocytogenes infections in the United States, but avocado samples have yielded strains that were closely related genetically to clinical L. monocytogenes isolates. To determine whether avocados have been a source of listeriosis, we conducted a retrospective review of epidemiological data for clinical isolates that were genetically related to isolates from avocados. Using a national database, we identified clusters containing clinical and at least one avocado isolate. We then selected clusters based upon isolation dates, cluster and composition size, and available food history data. For each cluster, we assessed (i) whether avocado consumption was higher among case patients in the cluster than among those with sporadic illnesses and (ii) whether the only food isolates within the cluster were from avocados. If both conditions were met, the link was considered "likely," if one condition was met the link was considered "possible," and if neither condition was met evidence was "limited." Five of 15 clusters met the criteria for assessment. Of these, two were classified as having "limited" evidence for a link to avocados, two as "possible," and one as "likely." For the cluster considered "likely," avocado consumption was significantly higher among case patients in the cluster compared with sporadic illnesses (odds ratio, 8.5; 95% confidence interval, 1.5 to 86.5). We identified three clusters that were likely or possibly linked to avocados, which suggests that avocados could be a source of listeriosis in the United States. Messaging on safe handling might be warranted for groups at higher risk, but further research is first needed to better characterize the ecology of pathogens on avocados and the likelihood of internalization of L. monocytogenes.

HIGHLIGHTS

Phages in Food Industry Biocontrol and Bioremediation

Bacteriophages are ubiquitous in nature and their use is a current promising alternative in biological control. Multidrug resistant (MDR) bacterial strains are present in the livestock industry and phages are attractive candidates to eliminate them and their biofilms. This alternative therapy also reduces the non-desirable effects produced by chemicals on food. The World Health Organization (WHO) estimates that around 420,000 people die due to a foodborne illness annually, suggesting that an improvement in food biocontrol is desirable. This review summarizes relevant studies of phage use in biocontrol focusing on treatments in live animals, plants, surfaces, foods, wastewaters and bioremediation.

Phages in Food Industry Biocontrol and Bioremediation

Bacteriophages are ubiquitous in nature and their use is a current promising alternative in biological control. Multidrug resistant (MDR) bacterial strains are present in the livestock industry and phages are attractive candidates to eliminate them and their biofilms. This alternative therapy also reduces the non-desirable effects produced by chemicals on food. The World Health Organization (WHO) estimates that around 420,000 people die due to a foodborne illness annually, suggesting that an improvement in food biocontrol is desirable. This review summarizes relevant studies of phage use in biocontrol focusing on treatments in live animals, plants, surfaces, foods, wastewaters and bioremediation.

An Update Review on Listeria Infection in Pregnancy

Listeria monocytogenes (LM) is an intracellular, aerobic and facultative anaerobic, Gram-positive bacterium, which is primarily transmitted to humans orally via food. LM could occur in asymptomatic pregnant women; however, fetal infection is a serious condition, entailing premature birth, abortion, sepsis, central nervous system (CNS) involvement, or even death. If a pregnant woman exhibits symptoms, the performance is almost like influenza, such as fever, headache, diarrhea, myalgia, or other digestive-related symptoms. This review collected clinical and empirical results regarding the mechanism, clinical manifestations, obstetrical outcome, diagnosis, treatment, vertical transmission, neonatal infection, and prevention of listeriosi according to articles published in PubMed from January 1, 1980, to March 20, 2021. The early detection and diagnosis of pregnancy-associated listeriosis are significant since sensitive antibiotics are effective at enhancing the prognosis of newborns. Listeriosis can be diagnosed using positive cultures from maternal or neonatal blood, neonatal cerebrospinal fluid (CSF), amniotic fluid, intrauterine mucosa, or the placenta. Two weeks of high-dose intravenous amoxicillin (more than 6 g/day) is recommended for LM pregnant women without allergy. Terminating the pregnancy to save the mother’s life should be considered if maternal and fetal conditions aggravate. Neonatal Listeria infection is primarily transmitted through the placenta, which is a critical illness associated with a high mortality rate. The necessary dietary guidance for pregnant women can reduce the incidence rate of pregnancy-related listeriosis.

Neonatal listeriosis presentation and outcome: a prospective study of 189 cases

CONTEXT

Listeriosis is caused by the foodborne pathogen Listeria monocytogenes. It can present as a maternal-neonatal infection. We implemented the nationwide prospective cohort MONALISA and analyzed the features of neonatal listeriosis.

METHODS

We studied all neonates born alive from mothers with microbiologically-proven maternal-neonatal listeriosis enrolled from November 2009 to December 2017. We analyzed presentation, neonatal outcome at discharge and predictors of severe presentation and outcome. The study is registered at clinicaltrials.gov (NCT01520597).

RESULTS

We studied 189 infants. 133/189 (70%) had abnormal clinical status at birth, including acute respiratory distress in 106/189 (56%). 132/189 (70%) infants developed early-onset listeriosis and 12/189 (6%) late onset listeriosis who all presented with acute meningitis. 17/189 (9%) had major adverse outcomes: 3% death (5/189), 6% (12/189) severe brain injury, 2% (3/189) severe bronchopulmonary dysplasia, 15/17 in infants born < 34 weeks of gestation (p < 0.0001 versus infants born ≥ 34 weeks of gestation). Maternal antimicrobial treatment ≥ 1 day before delivery was associated with a significant decrease of infants' severity (resulting in significantly less inotropic drugs, fluid resuscitation, or mechanical ventilation requirement), OR 0.23 [95% confidence interval CI 0.09-0.51], p < 0.0001).

CONCLUSION

Antenatal maternal antimicrobial treatment is associated with reduced neonatal listeriosis severity, justifying the prescription of preemptive maternal antimicrobial therapy when maternal-fetal listeriosis is suspected. Neonatal outcome is better than reported earlier, and its major determinant is gestational age at birth.

Listeria monocytogenes, a model in infection biology

Listeria monocytogenes causes listeriosis, a systemic infection which manifests as bacteremia, often complicated by meningoencephalitis in immunocompromised individuals and the elderly, and fetal-placental infection in pregnant women. It has emerged over the past decades as a major foodborne pathogen, responsible for numerous outbreaks in Western countries, and more recently in Africa. L. monocytogenes' pathogenic properties have been studied in detail, thanks to concomitant advances in biological sciences, in particular molecular biology, cell biology and immunology. L. monocytogenes has also been instrumental to basic advances in life sciences. L. monocytogenes therefore stands both a tool to understand biology and a model in infection biology. This review briefly summarises the clinical and some of the pathophysiological features of listeriosis. In the context of this special issue, it highlights some of the major discoveries made by Pascale Cossart in the fields of molecular and cellular microbiology since the mid-eighties regarding the identification and characterisation of multiple bacterial and host factors critical to L. monocytogenes pathogenicity. It also briefly summarises some of the key findings from our laboratory on this topic over the past years.

Maternal-neonatal listeriosis

Listeriosis is a rare and severe foodborne infection caused by Listeria monocytogenes. It manifests as septicemia, neurolisteriosis, and maternal-fetal infection. In pregnancy, it may cause maternal fever, premature delivery, fetal loss, neonatal systemic and central nervous system infections. Maternal listeriosis is mostly reported during the 2nd and 3rd trimester of pregnancy, as sporadic cases or in the context of outbreaks. Strains belonging to clonal complexes 1, 4 and 6, referred to as hypervirulent, are the most associated to maternal-neonatal infections. Here we review the clinical, pathophysiological, and microbiological features of maternal-neonatal listeriosis.

Maternal Immunological Adaptation During Normal Pregnancy

The risk and severity of specific infections are increased during pregnancy due to a combination of physiological and immunological changes. Characterizing the maternal immune system during pregnancy is important to understand how the maternal immune system maintains tolerance towards the allogeneic fetus. This may also inform strategies to prevent maternal fatalities due to infections and optimize maternal vaccination to best protect the mother-fetus dyad and the infant after birth. In this review, we describe what is known about the immunological changes that occur during a normal pregnancy.

Laboratory-based surveillance of invasive listeriosis in Northern Italy over a fourteen-year period: epidemiological and clinical results

Introduction

Invasive listeriosis is a rare foodborne disease with a significant impact on public health worldwide, because of the severity of its clinical manifestations and high fatality rate. In this study, we provide a snapshot of epidemiology of listeriosis in Lombardy Region, Northern Italy, reviewing enhanced surveillance data collected over fourteen years, after the implementation of a voluntary laboratory-based surveillance system for the referral of clinical isolates of Listeria monocytogenes to a regional reference laboratory, since 2005.

Methods

Invasive listeriosis cases data from 2005 to 2018 were extracted from the regional laboratory-based surveillance system database and compared with the regional mandatory notification disease system data.

Results

Over the fourteen-year period under study, 533 Listeria monocytogenes isolates were detected by the laboratory surveillance system, 55 of which from pregnancy-related cases. The median age of non-pregnancy-associated patients was 71 years, with 64.6% of cases observed in the elderly. Cases with underlying medical risk conditions accounted for 92.1%, and the fatality rate was 26.2%. By integrating data from the mandatory notification system and the laboratory-based surveillance system, a total of 935 cases were recorded. The collection of data through the laboratory surveillance system allowed to increase the surveillance sensitivity by 18%.

Conclusions

Our results documented the growing epidemiological relevance of listeriosis through the analysis of two information sources, the regional mandatory notification system and the regional laboratory-based surveillance system. The data we obtained were consistent with the literature, except for pregnancy-related cases, which are often underdiagnosed. This study highlighted the importance of laboratory-based surveillance system, which led to a significant increase in the sensitivity of the mandatory notification system.

Host syndecan-1 promotes listeriosis by inhibiting intravascular neutrophil extracellular traps

Heparan sulfate proteoglycans (HSPGs) are at the forefront of host-microbe interactions. Molecular and cell-based studies suggest that HSPG-pathogen interactions promote pathogenesis by facilitating microbial attachment and invasion of host cells. However, the specific identity of HSPGs, precise mechanisms by which HSPGs promote pathogenesis, and the in vivo relevance of HSPG-pathogen interactions remain to be determined. HSPGs also modulate host responses to tissue injury and inflammation, but functions of HSPGs other than facilitating microbial attachment and internalization are understudied in infectious disease. Here we examined the role of syndecan-1 (Sdc1), a major cell surface HSPG of epithelial cells, in mouse models of Listeria monocytogenes (Lm) infection. We show that Sdc1-/- mice are significantly less susceptible to both intragastric and intravenous Lm infection compared to wild type (Wt) mice. This phenotype is not seen in Sdc3-/- or Sdc4-/- mice, indicating that ablation of Sdc1 causes a specific gain of function that enables mice to resist listeriosis. However, Sdc1 does not support Lm attachment or invasion of host cells, indicating that Sdc1 does not promote pathogenesis as a cell surface Lm receptor. Instead, Sdc1 inhibits the clearance of Lm before the bacterium gains access to its intracellular niche. Large intravascular aggregates of neutrophils and neutrophil extracellular traps (NETs) embedded with antimicrobial compounds are formed in Sdc1-/- livers, which trap and kill Lm. Lm infection induces Sdc1 shedding from the surface of hepatocytes in Wt livers, which is directly associated with the decrease in size of intravascular aggregated NETs. Furthermore, administration of purified Sdc1 ectodomains or DNase inhibits the formation of intravascular aggregated neutrophils and NETs and significantly increases the liver bacterial burden in Sdc1-/- mice. These data indicate that Lm induces Sdc1 shedding to subvert the activity of Sdc1 ectodomains to inhibit its clearance by intravascular aggregated NETs.

Heterogeneity, Characteristics, and Public Health Implications of Listeria monocytogenes in Ready-to-Eat Foods and Pasteurized Milk in China

Listeria monocytogenes is a foodborne pathogen with a high mortality rate in humans. This study aimed to identify the pathogenic potential of L. monocytogenes isolated from ready-to-eat (RTE) foods and pasteurized milk in China on the basis of its phenotypic and genotypic characteristics. Approximately 7.7% (44/570) samples tested positive for L. monocytogenes among 10.8% (39/360) RTE and 2.4% (5/210) pasteurized milk samples, of which 77.3% (34/44) had < 10 MPN/g, 18.2% (8/44) had 10-110 MPN/g, and 4.5% (2/44) had > 110 MPN/g. A total of 48 strains (43 from RTE foods and five from milk samples) of L. monocytogenes were isolated from 44 positive samples. PCR-serogroup analysis revealed that the most prevalent serogroup was II.2 (1/2b-3b-7), accounting for 52.1% (25/48) of the total, followed by serogroup I.1 (1/2a-3a) accounting for 33.3% (16/48), serogroup I.2 (1/2c-3c) accounting for 12.5% (6/48), and serogroup II.1 (4b-4d-4e) accounting for 2.1%. All isolates were grouped into 11 sequence types (STs) belonging to 10 clonal complexes (CCs) and one singleton (ST619) via multi-locus sequence typing. The most prevalent ST was ST87 (29.2%), followed by ST8 (22.9%), and ST9 (12.5%). Virulence genes determination showed that all isolates harbored eight virulence genes belonging to Listeria pathogenicity islands 1 (LIPI-1) (prfA, actA, hly, mpl, plcA, plcB, and iap) and inlB. Approximately 85.4% isolates carried full-length inlA, whereas seven isolates had premature stop codons in inlA, six of which belonged to ST9 and one to ST5. Furthermore, LLS (encoded by llsX gene, representing LIPI-3) displays bactericidal activity and modifies the host microbiota during infection. LIPI-4 enhances neural and placental tropisms of L. monocytogenes. Results showed that six (12.5%) isolates harbored the llsX gene, and they belonged to ST1/CC1, ST3/CC3, and ST619. Approximately 31.3% (15/48) isolates (belonging to ST87/CC87 and ST619) harbored ptsA (representing LIPI-4), indicating the potential risk of this pathogen. Antimicrobial susceptibility tests revealed that > 95% isolates were susceptible to 16 antimicrobials; however, 60.4 and 22.9% isolates were intermediately resistant to streptomycin and ciprofloxacin, respectively. The results show that several isolates harbor LIPI-3 and LIPI-4 genes, which may be a possible transmission route for Listeria infections in consumers.

Neurologic infections during pregnancy

Neurologic infections during pregnancy represent a significant cause of maternal and fetal morbidity and mortality. Immunologic alterations during pregnancy increase the susceptibility of the premature brain to damage. This chapter summarizes the epidemiology, pathophysiology, and clinical manifestations in the pregnant woman and the infant, and the diagnosis, treatment, and prevention of the major viral, parasitic, and bacterial infections known to affect pregnancy. These organisms include herpes virus, parvovirus, cytomegalovirus, varicella, rubella, Zika virus, toxoplasmosis, malaria, group B streptococcus, listeriosis, syphilis, and tuberculosis. There is an emphasis on the important differences in diagnosis, treatment, and fetal outcome between trimesters. An additional overview is provided on the spectrum of neurologic sequelae of an affected infant, which ranges from developmental delay to hydrocephalus and seizures.

Multistate Outbreak of Listeriosis Associated with Packaged Leafy Green Salads, United States and Canada, 2015-2016

We investigated an outbreak of listeriosis detected by whole-genome multilocus sequence typing and associated with packaged leafy green salads. Nineteen cases were identified in the United States during July 5, 2015–January 31, 2016; isolates from case-patients were closely related (median difference 3 alleles, range 0–16 alleles). Of 16 case-patients interviewed, all reported salad consumption. Of 9 case-patients who recalled brand information, all reported brands processed at a common US facility. The Public Health Agency of Canada simultaneously investigated 14 cases of listeriosis associated with this outbreak. Isolates from the processing facility, packaged leafy green salads, and 9 case-patients from Canada were closely related to US clinical isolates (median difference 3 alleles, range 0–16 alleles). This investigation led to a recall of packaged leafy green salads made at the processing facility. Additional research is needed to identify best practices and effective policies to reduce the likelihood of Listeria monocytogenes contamination of fresh produce.

Whole-genome sequencing reveals Listeria monocytogenes diversity and allows identification of long-term persistent strains in Brazil

Advances in whole-genome sequencing (WGS) technologies have documented genetic diversity and epidemiology of the major foodborne pathogen Listeria monocytogenes (Lm) in Europe and North America, but data concerning South America are scarce. Here, we examined the population structure and genetic diversity of this major foodborne pathogen collected in Brazil. Based on core genome multilocus sequence typing (cgMLST), isolates from lineages I (n = 22; 63%) and II (n = 13; 37%) were distributed into 10 different sublineages (SLs) and represented 31 new cgMLST types (CTs). The most prevalent SLs were SL9 (n = 9; 26%), SL3 (n = 6; 17%) and SL2 and SL218 (n = 5; 14%). Isolates belonging to CTs L2-SL9-ST9-CT4420 and L1-SL315-ST520-CT4429 were collected 3 and 9 years apart, respectively, revealing long-term persistence of Lm in Brazil. Genetic elements associated with stress survival were present in 60% of isolates (57% SSI-1 and 3% SSI-2). Pathogenic islands were present in 100% (LIPI-1), 43% (LIPI-3) and 6% (LIPI-4) of the isolates. Mutations leading to premature stop codons were detected in the prfA and inlA virulence genes. This study is an important contribution to understanding the genomic diversity and epidemiology of Lm in South America. In addition, the results highlight the importance of using WGS to reveal Lm long-term persistence.

Sentinel Listeriosis Surveillance in Selected Hospitals, China, 2013-2017

During 2013-2017, a total of 211 cases of listeriosis were reported by 64 sentinel hospitals in China to a national foodborne disease surveillance network. The average case-fatality rate was 31.2% for perinatal cases and 16.4% for nonperinatal cases. Sequence types 87 and 8 were the most prevalent types.

Alfa-1-antitrypsin deficiency: a predisposing factor leading to invasive infections?

This case report highlights for the first time a possible link between the presence of alfa-1-antitrypsin deficiency (AATD) and the susceptibility to invasive infections. The current patient, with known AATD, initially presented with nausea, vomiting and headache secondary to Listeria monocytogenes rhombencephalitis. Further on, he developed respiratory insufficiency due to probable invasive pulmonary aspergillosis. Diagnostic work-up could not show any arguments for an underlying immunodeficiency or malignancy. The consecutive course of two rare invasive infections in a healthy individual posed the hypothesis if the underlying AATD could be considered a possible trigger for infections. Indirect clinical observations in literature indeed support this link and in addition, two possible pathophysiological pathways might explain the higher susceptibility for infections in AATD patients. First, alveolar macrophages are dysfunctional in AATD patients leading to a lower apoptotic clearance of bacteria and other (mostly intracellular) pathogens. Secondly, a lower release and lower function of tumour necrosis factor α (TNFα) is seen in alfa-1-antitrypsin depletion, priming the path to more frequent infections, a mechanism that is similar in anti-TNFα treated patients. This case is the first to report on severe or invasive infections related to AATD in humans.

Imaging of Human Neurolisteriosis: A Prospective Study of 71 Cases

Background

Neurolisteriosis ranks among the most severe neurological infections. Its radiological features have not been thoroughly studied. We describe here the neuroradiological features of neurolisteriosis and assess their prognostic value.

Methods

Patients with microbiologically proven neurolisteriosis were enrolled from November 2009 to October 2013 in MONALISA study. Magnetic resonance and computed tomography images were studied by 2 independent neuroradiologists. Predictors of 3-month mortality were determined using logistic regression.

Results

Seventy-one patients were included; 42 were men (59%). Mean age was 64 years. Sixty patients (85%) reported signs of encephalitis, with clinical brainstem involvement in 16 (23%). Images were abnormal in 87% of cases (62/71). Main neuroradiological images were meningeal enhancement (25/71, 35%), abscess(es), or nodular image(s) evocative of abscess (10/71, 14%), hemorrhages (11/71, 15%), contrast-enhancing ventricles, or hydrocephalus (7/71, 10%). White-matter images (42/71, 59%), dilated Virchow-Robin spaces (22/71, 31%), and cerebral atrophy were also reported (34/71, 48%). Brainstem involvement (meningeal enhancement, abscess) was reported in only 7/71 cases (10%). Three-month survival was lower in patients with hydrocephalus or contrast-enhancing ventricles (1/7 [14%] than without [47/64, 73%], P = .005) and in patients with parenchymal images (abscess[es], nodule[s]\, or white matter images; 25/46 [54%] vs 23/25 without [92%], P = .004). Parenchymal images were associated with lower 3-month survival in the multivariable model (odds ratio 5.60, 95% confidence interval [1.42-29.6], P = .02).

Conclusions

Neurolisteriosis presents as a combination of neuroradiological images, none being specific. Radiological signs of rhombencephalitis are uncommon, whereas, unexpectedly, hemorrhagic images are frequent. The negative prognostic value of parenchymal neuroradiological images was evidenced.

Clinical Trials Registration

NCT01520597.

Non-thermal inactivation of Listeria spp. in a typical dry-fermented sausage: "Bergamasco" salami

Aim of the present study was the evaluation of the growth potential of Listeria spp. inoculated in the typical North Italian dry fermented sausage "Bergamasco" salami during its production. As it was necessary to carry out the challenge test in the production line of the industry, according to the guidelines of the European Reference Laboratory for Listeria monocytogenes, a non-pathogenic "surrogate" microorganism was used: for the inoculum, two strains of Listeria innocua (1 ATCC, 1 strain isolated from a similar substrate) were used. The inoculation of the samples occurred during grinding and mixing of the sausage mass, before the filling. To avoid cross-contamination, the control samples were produced before the contaminated ones. After the dripping, salamis were subjected to the normal production process (drying and maturation in five steps at specific temperatures and humidity rates). The inoculated products were subjected to the enumeration of Listeria spp. at T0 (day of inoculation) and at T4 (post-drying), and every 10 days during curing (T10, T20, T30, T40, T50, T60, T70, T80 and T90), as this salami is generally sold as whole piece with varying levels of curing (from T20 to T90). Since the product may be cut in half and vacuumpacked, at each of the times starting from T20, half salami was vacuum-packed and stored for 30 days at 12°C, at the end of the which Listeria spp. enumeration was performed again. At all times and for each type of samples of each of the three batches, the enumeration of the natural microflora (Total Viable Count, lactic acid bacteria, Pseudomonas spp., Enterobacteriaceae) and the determination of water activity and pH were performed on control samples. The product was characterized by a high concentration of microflora (8-8.5 Log UFC/g), consisting mainly of lactic acid bacteria, added to the mixture at the beginning of the production process. The pH showed a decrease over time, expected for this type of products, due to the development of lactic acid bacteria (final pH: 5.42-5.55). The water activity reached values able to inhibit the development of Listeria spp. (final aw: 0.826-0.863). Listeria counts in the tested batches of "Bergamasco" salami showed the absence of significant growth in the product with a reduction of loads if compared to T0, between -0.59 and -1.04 Log CFU/g. Even in the samples subjected to vacuum packaging and storage at 12°C, the absence of significant increase of lactic acid bacteria in the product was highlighted with further decrease of bacterial loads (-0.70/-0.79 Log CFU/g if compared to T20). Considering the worst case scenario (thus the batch with the highest growth potential), in the products stored in the curing room at 14-16°C, at humidity of 80% and in the samples stored at 12°C and vacuum packaged, the threshold indicated by the EURL Lm guidelines (+0.5 Log CFU/g) for the growth of Listeria spp. was not reached, allowing to classify "Bergamasco" salami in the category 1.3 of the EC Reg. 2073/2005 as "Ready-to-eat food unable to support the growth of Listeria monocytogenes".

Food Safety Knowledge and Self-Reported Food-Handling Practices in Cancer Treatment

OBJECTIVES

To explore awareness of foodborne infection risk during chemotherapy treatment, to assess knowledge of risk-reducing food safety practices in patients with cancer and their family caregivers, and to determine self-reported food-handling practices.

SAMPLE & SETTING

A convenience sample of 121 patients receiving chemotherapy and 51 family caregivers of patients receiving chemotherapy in the United Kingdom recruited in the community and using online advertising.

METHODS & VARIABLES

Participants completed a self-report questionnaire to determine food safety knowledge and self-reported food-handling practices.

RESULTS

Although patients receiving chemotherapy and family caregivers reported awareness of food safety practices, self-reported practices indicated that potentially unsafe practices may be used in relation to temperature control, handwashing, safe cooking, and adherence to use-by dates. Such practices may increase the risk of foodborne illness to patients receiving chemotherapy treatment.

IMPLICATIONS FOR NURSING

Nursing research is required to explore the food safety training and awareness of healthcare providers. Highly focused and specifically targeted food safety interventions need to be developed and delivered to increase awareness and to implement food safety practices.