Outbreak of Listeriosis in South Africa Associated with Processed Meat.

BACKGROUND: An outbreak of listeriosis was identified in South Africa in 2017. The source was unknown. METHODS: We conducted epidemiologic, trace-back, and environmental investigations and used whole-genome sequencing to type Listeria monocytogenes isolates. A case was defined as laboratory-confirmed L. monocytogenes infection during the period from June 11, 2017, to April 7, 2018. RESULTS: A total of 937 cases were identified, of which 465 (50%) were associated with pregnancy; 406 of the pregnancy-associated cases (87%) occurred in neonates. Of the 937 cases, 229 (24%) occurred in patients 15 to 49 years of age (excluding those who were pregnant). Among the patients in whom human immunodeficiency virus (HIV) status was known, 38% of those with pregnancy-associated cases (77 of 204) and 46% of the remaining patients (97 of 211) were infected with HIV. Among 728 patients with a known outcome, 193 (27%) died. Clinical isolates from 609 patients were sequenced, and 567 (93%) were identified as sequence type 6 (ST6). In a case-control analysis, patients with ST6 infections were more likely to have eaten polony (a ready-to-eat processed meat) than those with non-ST6 infections (odds ratio, 8.55; 95% confidence interval, 1.66 to 43.35). Polony and environmental samples also yielded ST6 isolates, which, together with the isolates from the patients, belonged to the same core-genome multilocus sequence typing cluster with no more than 4 allelic differences; these findings showed that polony produced at a single facility was the outbreak source. A recall of ready-to-eat processed meat products from this facility was associated with a rapid decline in the incidence of L. monocytogenes ST6 infections. CONCLUSIONS: This investigation showed that in a middle-income country with a high prevalence of HIV infection, L. monocytogenes caused disproportionate illness among pregnant girls and women and HIV-infected persons. Whole-genome sequencing facilitated the detection of the outbreak and guided the trace-back investigations that led to the identification of the source.

Listeriosis associated with pre-prepared sandwich consumption in hospital in England, 2017.

A case of listeriosis occurred in a hospitalised patient in England in July 2017. Analysis by whole genome sequencing of the Listeria monocytogenes from the patient's blood culture was identified as clonal complex (CC) 121. This culture was indistinguishable to isolates from sandwiches, salads and the maufacturing environment of Company X which supplied these products widely to the National Health Service. Whilst an inpatient, the case was served sandwiches produced by this company on 12 occasions. No other cases infected by this type were detected in the UK between 2016 and 2020. Between 2016 and 2020, more than 3000 samples of food, food ingredients and environmental swabs from this company were tested. Listeria monocytogenes contamination rates declined after July 2017 from 31% to 0.3% for salads and 3% to 0% for sandwiches. A monophyletic group of 127 L. monocytogenes CC121 isolates was recovered during 2016-2019 and was used to estimate the time of the most recent common ancestor as 2014 (95% CI of between 2012 and 2016). These results represent persistent contamination of equipment, food contact surfaces and foods at a food manufacturer by a single L. monocytogenes strain. Colonisation and persistent contamination of food and production environments are risks for public health.

Intraperitoneal ampicillin treatment for peritoneal dialysis- related peritonitis with Listeria monocytogenes - a case report.

BACKGROUND: Peritoneal dialysis (PD)-related peritonitis is a rare but serious complication and is associated with increased morbidity and mortality rates. It is most commonly caused by Staphylococcus aureus or Staphylococcus epidermidis, but infection with Listeria monocytogenes may also occur. Recommendations for antibiotic treatment of a Listeria infection are currently based on a small number of case reports and suggest the administration of ampicillin. But unlike vancomycin or gentamicin, for ampicillin the route of application, the dosage, and the duration of treatment have not yet been established. We report a case in which PD-associated peritonitis due to Listeria infection was treated with ampicillin administered intravenously and intraperitoneally, separately and in combination. CASE PRESENTATION: A 72-year-old man with chronic kidney disease stage 5 dialysis (CKDG5D) secondary to hypertension and diabetes was hospitalised in April 2020 because of PD-related peritonitis caused by a Listeria infection. In accordance with the results of resistance tests, the patient was treated with intravenous ampicillin at a dosage of 6 g twice daily. After initial treatment the leukocyte count in the PD effluent had decreased substantially, but it was permanently reduced only with the addition of intraperitoneal ampicillin (4 g daily). Efficient serum concentrations of ampicillin were determined for both routes of administration, intravenous and intraperitoneal. CONCLUSION: This is the first case report demonstrating that PD-related peritonitis due to Listeria monocytogenes infection can be treated with intraperitoneal ampicillin and monitored by the determination of peripheral serum concentrations of ampicillin.

[A Case of Aortic Graft Infection Due to Listeria monocytogenes Detected by Microarray-Based, Multiplexed, Automated Molecular Diagnosis System].

A 80-year-old man was transferred to our hospital for hemoptysis caused by erosion(perforation) of thoracic aortic stent graft infection into the airway. Blood cultures on admission detected Gram-positive rods, and a microarray-based, multiplexed, automated molecular diagnosis instrument (Verigene® system) identified Listeria spp. Although Listeria monocytogenes is rare organism of stent graft infection, we were able to start appropriate antibiotic therapy on the second hospital day due to rapid identification of bacteria. Verigene® system is considered to be useful in severe infectious diseases including stent graft infections, even if the causative organism is rare.

An outbreak of listeriosis linked to turkey meat products in the Czech Republic, 2012-2016.

Since 2012-2016 an increased number of listeriosis cases, especially from one region of the Czech Republic, were observed. Most of them were caused by strains of serotype 1/2a, clonal complex 8, indistinguishable by pulsed-field gel electrophoresis. Twenty-six human cases were reported, including two neonatal cases in twins. Three cases were fatal. The typing of Listeria monocytogenes isolates from food enabled to confirm a turkey meat delicatessen as the vehicle of infection for this local outbreak in the Moravian-Silesian Region. The food strains belonging to identical pulsotype were isolated from ready-to-eat turkey meat products packaged by the same producer between 2012 and 2016. This fact confirms that the described L. monocytogenes outbreak strain probably persisted in the environment of the aforementioned food-processing plant over several years. Whole-genome sequencing confirmed a very close relationship (zero to seven different alleles) between isolates from humans, foods and swabs from the environment of the food-processing plant under investigation.

Use of Proton Pump Inhibitors and the Risk of Listeriosis: A Nationwide Registry-based Case-Control Study.

BACKGROUND: Recent studies suggest that proton pump inhibitors (PPIs) may increase the risk for listeriosis. We investigated a potential association in cases of nonpregnancy-associated listeriosis using registry data. METHODS: We conducted a population-based, case-control study using Danish health registries. Cases (n = 721) were defined as patients aged ≥45 years notified with listeriosis from July 1994 to December 2012. We selected 34800 controls using risk-set sampling. Controls were individually matched for age, sex, and municipality. Data on use of PPIs and other drugs and hospitalization diagnoses over a 5-year period were extracted from nationwide health registries. A comorbidity index (CMI) was constructed. We calculated the association between use of PPIs and related drugs within 30 days (current use) and other time windows before the index date. Using conditional logistic regression, matched odds ratios (ORs) adjusted for CMI and confounders were estimated. RESULTS: The adjusted OR for current use of PPIs and development of listeriosis was 2.81 (95% confidence interval [CI], 2.14-3.69). PPI usage up to 90 days before the index date remained statistically significant. Subgroup analyses revealed increasing ORs with decreasing age and level of comorbidity and an increased OR for concurrent glucocorticoid treatment (OR, 4.61; 95% CI, 3.01-7.06). No significant association was found for current use of histamine-2-receptor antagonists (adjusted OR, 1.82; 95% CI, 0.89-3.71). CONCLUSIONS: Prescribed PPIs were associated with increased risk of listeriosis. The risk waned with time since last prescription redemption. PPIs may have unwanted side effects in vulnerable populations.

Role of proapoptotic BH3-only proteins in Listeria monocytogenes infection.

The ability of pathogens to influence host cell survival is a crucial virulence factor. Listeria monocytogenes (Lm) infection is known to be associated with severe apoptosis of hepatocytes and spleen cells. This impairs host defense mechanisms and thereby facilitates the spread of intracellular pathogens. The general mechanisms of apoptosis elicited by Lm infection are understood, however, the roles of BH3-only proteins during primary Lm infection have not been examined. To explore the roles of BH3-only proteins in Lm-induced apoptosis, we studied Listeria infections in mice deficient in Bim, Bid, Noxa or double deficient in BimBid or BimNoxa. We found that BimNoxa double knockout mice were highly resistant to high-dose challenge with Listeria. Decreased bacterial burden and decreased host cell apoptosis were found in the spleens of these mice. The ability of the BH3-deficient mice to clear bacterial infection more efficiently than WT was correlated with increased concentrations of ROS, neutrophil extracellular DNA trap release and downregulation of TNF-α. Our data show a novel pathway of infection-induced apoptosis that enhances our understanding of the mechanism by which BH3-only proteins control apoptotic host cell death during Listeria infection.

Listeria monocytogenes infection associated with alemtuzumab - - a case for better preventive strategies.

BACKGROUND: The mortality of septicaemia, meningitis and encephalitis caused by Listeria monocytogenes is 20-40%. Twenty-one cases of invasive listeriosis associated with alemtuzumab, including at least 16 in patients with multiple sclerosis, have been published or reported to the World Health Organization Case Safety Reports Database. Three cases were fatal, including at least one patient treated for multiple sclerosis in 2016. CASE PRESENTATION: We report a patient with multiple sclerosis who developed pyrexia, nausea and abdominal discomfort few hours after the third and last infusion of her second alemtuzumab cycle. An infusion related reaction was suspected. The patient had however eaten soft cheese and raw sausage 3 days prior to treatment, and L. monocytogenes septicaemia was diagnosed based on positive blood cultures. CONCLUSION: Listeriosis associated with alemtuzumab is a potentially fatal condition that can mimic an infusion related reaction. As in most other previously reported cases symptoms started rapidly after the last infusion, suggesting that the patient already carried the bacteria prior to the alemtuzumab infusions. The summary of product characteristics recommends patients to avoid foods associated with listeria at least 1 month after treatment. This recommendation should include also the last weeks prior to treatment.

Unique case report of a chromomycosis and Listeria in soft tissue and cerebellar abscesses after kidney transplantation.

BACKGROUND: Chromomycosis is a rare mycotic infection encountered in tropical and subtropical regions. The disease presents as a slowly-evolving nodule that can become infected with bacteria. Here, we describe a unique association of abscesses caused by a chromomycosis and Listeria monocytogenes in a kidney transplant recipient, and didactically expose how the appropriate diagnosis was reached. CASE PRESENTATION: A 49-year old male originating from the Caribbean presented a scalp lesion which was surgically removed in his hometown where it was misdiagnosed as a sporotrichosis on histology, 3 years after he received a kidney transplant. He received no additional treatment and the scalp lesion healed. One year later, an abscess of each thigh due to both F. pedrosoi and L. monocytogenes was diagnosed in our institution. A contemporary asymptomatic cerebellar abscess was also found by systematic MRI. An association of amoxicillin and posaconazole allowed a complete cure of the patient without recurring to surgery. Histological slides from the scalp lesion were re-examined in our institution and we retrospectively concluded to a first localisation of the chromomycosis. We discuss the possible pathophysiology of this very unusual association. CONCLUSION: In this case of disseminated listeriosis and chromomycosis, complete cure of the patients could be reached with oral anti-infectious treatment only.

Listeria monocytogenes infection in ruminants: Is there a link to the environment, food and human health? A review.

Listeria (L.) monocytogenes is widely distributed in the environment, but also has the ability to cause serious invasive disease in ruminants and humans. This review provides an overview of listeriosis in ruminants and discusses our insufficient understanding of reservoirs and possible cycling ofL. monocytogenes between animal and human hosts, food and the environment. It indicates gaps in our knowledge of the role of genetic subtypes in L. monocytogenes ecology and virulence as well as risk factors, in vivo diagnostics and pathogenesis of listeriosis in ruminants. Filling these gaps will contribute to improving the control of L. monocytogenes and enhancing disease prevention. As the prevalence of listeriosis in ruminants in Switzerland is likely to be underestimated, propositions concerning improvement options for surveillance of listeriosis in ruminants are provided.

Risk-Based Approach for Microbiological Food Safety Management in the Dairy Industry: The Case of Listeria monocytogenes in Soft Cheese Made from Pasteurized Milk.

According to Codex Alimentarius Commission recommendations, management options applied at the process production level should be based on good hygiene practices, HACCP system, and new risk management metrics such as the food safety objective. To follow this last recommendation, the use of quantitative microbiological risk assessment is an appealing approach to link new risk-based metrics to management options that may be applied by food operators. Through a specific case study, Listeria monocytogenes in soft cheese made from pasteurized milk, the objective of the present article is to practically show how quantitative risk assessment could be used to direct potential intervention strategies at different food processing steps. Based on many assumptions, the model developed estimates the risk of listeriosis at the moment of consumption taking into account the entire manufacturing process and potential sources of contamination. From pasteurization to consumption, the amplification of a primo-contamination event of the milk, the fresh cheese or the process environment is simulated, over time, space, and between products, accounting for the impact of management options, such as hygienic operations and sampling plans. A sensitivity analysis of the model will help orientating data to be collected prioritarily for the improvement and the validation of the model. What-if scenarios were simulated and allowed for the identification of major parameters contributing to the risk of listeriosis and the optimization of preventive and corrective measures.

Listeriosis: not only during pregnancy.

Certain patients are exposed to an increased risk of listeriosis, particularly those with chronic lymphocytic leukaemia. It is better to inform them of the dietary and hygiene precautions to take to minimise this risk.

A critical role for interleukin 18 in primary and memory effector responses to Listeria monocytogenes that extends beyond its effects on Interferon gamma production.

The stimulation of interferon (IFN)-gamma by interleukin (IL)-12 has been shown to provide protection from intracellular pathogens such as Listeria monocytogenes. Tumor necrosis factor (TNF) is also a major player in the resolution of Listeria infections and is suggested to have more global effects than can be explained by the induction of IFN-gamma alone. Since IL-18 synergizes with IL-12 to induce IFN-gamma production by natural killer and T helper (Th)1 cells, we determined its role in responses to Listeria. IL-18 appeared to be even more potent than either IL-12 or IFN-gamma for protection against this pathogen and IL-18 enhanced bacterial clearance in the complete absence of IFN-gamma. Indeed IL-18 was comparable to TNF in its ability to resolve the infection and showed a lowered protective capacity in the absence of TNF. Moreover, IL-18 induced macrophages to secrete both TNF and nitric oxide after a Listeria infection. IL-18 was also essential for optimal IFN-gamma production by antigen-specific T cells. Therefore, IL-18 operates via its effects on both the innate immune response, including macrophages, as well as on Th1 cells, to protect against Listeria.

Modeling logistic performance in quantitative microbial risk assessment.

In quantitative microbial risk assessment (QMRA), food safety in the food chain is modeled and simulated. In general, prevalences, concentrations, and numbers of microorganisms in media are investigated in the different steps from farm to fork. The underlying rates and conditions (such as storage times, temperatures, gas conditions, and their distributions) are determined. However, the logistic chain with its queues (storages, shelves) and mechanisms for ordering products is usually not taken into account. As a consequence, storage times-mutually dependent in successive steps in the chain-cannot be described adequately. This may have a great impact on the tails of risk distributions. Because food safety risks are generally very small, it is crucial to model the tails of (underlying) distributions as accurately as possible. Logistic performance can be modeled by describing the underlying planning and scheduling mechanisms in discrete-event modeling. This is common practice in operations research, specifically in supply chain management. In this article, we present the application of discrete-event modeling in the context of a QMRA for Listeria monocytogenes in fresh-cut iceberg lettuce. We show the potential value of discrete-event modeling in QMRA by calculating logistic interventions (modifications in the logistic chain) and determining their significance with respect to food safety.

Listeriosis in pregnancy: survey of British Columbia practitioners' knowledge of risk factors, counseling practices, and learning needs.

OBJECTIVE: To determine the knowledge, counseling practices, and learning needs of practitioners in British Columbia regarding risk factors for listeriosis in pregnancy. DESIGN: A 1-page, mailed, self-administered, anonymous questionnaire. SETTING: British Columbia. PARTICIPANTS: A total of 827 practitioners (614 family physicians, 93 midwives, and 120 family practice residents) were sent the questionnaire. MAIN OUTCOME MEASURES: Awareness of listeriosis, knowledge of the risk factors for listeriosis, practices for counseling pregnant women, practitioners' learning needs, and provider and practice characteristics. RESULTS: A total of 340 practitioners (41%) completed the questionnaire. While most (88%) physicians and midwives had heard of listeriosis, few (18%) were aware that infection was more common during pregnancy. One-third (33%) of practitioners counseled pregnant women about the risk factors for listeriosis. The main reasons for not providing such counseling were lack of knowledge and the perception that listeriosis was rare and not an important concern for pregnant women. Rates of counseling were highest among midwives (84%) and lowest among physicians practising outside the Lower Mainland of British Columbia (12%). Of those practitioners providing prenatal care, 47% counseled pregnant women about the risks of unpasteurized milk and 41% counseled women about the risks of consuming soft cheese; few counseled about the risks of consuming deli meat or raw hot dogs (25%), unwashed fruit and vegetables (12%), or refrigerated smoked seafood (6%). CONCLUSION: Most prenatal care providers in British Columbia are unaware of the risk factors for listeriosis or its propensity for pregnant women and do not counsel their pregnant patients about these risks.

[Listeriosis in non-Hodgkin's lymphoma following outpatient R-CHOP therapy].

Non-Hodgkin's lymphoma, a hematolymphoid malignancy, puts subjects at risk for complete infection. A 65-year-old man with non-Hodgkin's lymphoma Stage IV had undergone 5 R-CHOP courses in May 2008. Six days later, he was hospitalized for a high fever for which he was initially administered cefepime. When blood culture was positive for Listeria monocytogenes, he was administered ampicillin. His medical interview indicated that he had gone hunting and dressed wild animal meat at his mountain retreat, where he was exposed to wild animals and their excreta following R-CHOP course 5. CSF was not checked because his general condition was good. On hospital day 2, his fever dropped, and he was discharged following two weeks of ampicillin administration. Listeriosis cases reported in Japan number far fewer than in the United States, France or Germany. From January 1983 to February 2009, 153 cases were reported in Japan, 12 of whom were cancer patients. Despite the high incidence of meningitis with listeriosis, 7 of the 12 were not examined for CSF--an examination necessary in listeriosis, however well the subject appears.

Enrichment of Neutrophils and Monocytes From the Liver Following Either Oral or Intravenous Listeria monocytogenes Infection.

Listeria monocytogenes is a foodborne pathogen that causes serious, often deadly, systemic disease in susceptible individuals such as neonates and the elderly. These facultative intracellular bacteria have been an invaluable tool in immunology research for more than three decades. Intravenous (i.v.) injection is the most commonly used transmission route in mice, but oral models of infection have also been developed in recent years, and these may be more appropriate for many studies. This article includes detailed instructions for use of either foodborne or i.v. inoculation of mice and discusses the rationale for choosing either model. Additionally, a protocol is provided for enrichment of neutrophils and monocytes from the infected liver in a manner that allows for determination of bacterial burden while still providing sufficient cells for use in flow cytometric analysis or in vitro assays. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Foodborne L. monocytogenes infection Support Protocol 1: Preparing L. monocytogenes for foodborne infection Basic Protocol 2: Intravenous L. monocytogenes infection Support Protocol 2: Preparing L. monocytogenes for intravenous infection Basic Protocol 3: Enrichment of non-parenchymal cells from the infected liver.