Invasive Listeria monocytogenes infections in the Netherlands, 1995-2003

A decision analysis of cancer patients and the consumption of ready-to-eat salad

Listeria monocytogenes is a foodborne pathogen of concern for cancer patients, who face higher morbidity and mortality rates than the general population. The neutropenic diet (ND), which excludes fresh produce, is often utilized to mitigate this risk; however, an analysis weighing the theoretical listeriosis risk reduction of produce exclusion aspects of the ND and possible negative tradeoffs has never been conducted. Consequently, this work constructed decision analytic models using disability-adjusted life years (DALYs) to compare the impacts of the ND, such as increased neutropenic enterocolitis (NEC) likelihood, with three alternative dietary practices (safe food handling [SFH], surface blanching, and refrigeration only) across five age groups, for cancer patients who consume ready-to-eat salad. Less disruptive diets had fewer negative health impacts in all scenarios, with median alternative diet DALYs per person per chemotherapy cycle having lower values in terms of negative health outcomes (0.088-0.443) than the ND (0.619-3.102). DALYs were dominated by outcomes associated with NEC, which is more common in patients following the ND than in other diets. Switchover point analysis confirmed that, because of this discrepancy, there were no feasible values of other parameters that could justify the ND. Correspondingly, the sensitivity analysis indicated that NEC mortality rate and remaining life expectancy strongly affected DALYs, further illustrating the model's strong dependence on NEC outcomes. Given these findings, and the SFH's ease of implementation and high compliance rates, the SFH diet is recommended in place of the ND.

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.

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.

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.

Implicated Food Products for Listeriosis and Changes in Serovars of Listeria monocytogenes Affecting Humans in Recent Decades

Listeriosis is a foodborne disease with a high fatality rate, and infection is mostly transmitted through ready-to-eat (RTE) foods contaminated with Listeria monocytogenes, such as gravad/smoked fish, soft cheeses, and sliced processed delicatessen (deli) meat. Food products/dishes stored in vacuum or in modified atmospheres and with extended refrigerator shelf lives provide an opportunity for L. monocytogenes to multiply to large numbers toward the end of the shelf life. Elderly, pregnant women, neonates, and immunocompromised individuals are particularly susceptible to L. monocytogenes. Listeriosis in humans manifests primarily as septicemia, meningitis, encephalitis, gastrointestinal infection, and abortion. In the mid 1990s and early 2000s a shift from L. monocytogenes serovar 4b to serovar 1/2a causing human listeriosis occurred, and serovar 1/2a is becoming more frequently linked to outbreaks of listeriosis, particularly in Europe and Northern America. Consumer lifestyle has changed, and less time is available for food preparation. Modern lifestyle has markedly changed eating habits worldwide, with a consequent increased demand for RTE foods; therefore, more RTE and take away foods are consumed. There is a concern that many Listeria outbreaks are reported from hospitals. Therefore, it is vitally important that foods (especially cooked and chilled) delivered to hospitals and residential homes for senior citizens and elderly people are reheated to at least 72°C: cold food, such as turkey deli meat and cold-smoked and gravad salmon should be free from L. monocytogenes. Several countries have zero tolerance for RTE foods that support the growth of Listeria.

Epidemiology and Molecular Typing of Pregnancy-Associated Listeriosis Cases in Lombardy, Italy, over a 10-Year Period (2005-2014)

In developed countries, pregnancy-related listeriosis accounts for 20–43% of total invasive listeriosis. This work describes the first pregnancy-related listeriosis survey in Italy based on two data sources, that is, mandatory notification system and regional laboratory-based network. Out of 610 listeriosis cases reported over a 10-year period, 40 were pregnancy-related (6.6%). Among these, 29 pregnancy-related isolates were available and have been analysed with serotyping, Pulsed-Field Gel Electrophoresis, and Multi-Virulence-Locus Sequence Typing. No maternal fatality was recorded, but 11 (29.7%) pregnancies resulted in a foetal death, a miscarriage, or a birth of a foetus dying immediately after birth. The average incidence of pregnancy-related listeriosis was 4.3 cases per 100000 births, and the proportion of pregnancy-associated listeriosis among ethnic minorities was significantly higher compared to the general population (30.0% versus 3.5%, P < 0.01). L. monocytogenes isolates belonged to serotypes 1/2a, 1/2b, and 4b, with the latter significantly more prevalent among pregnancy-related isolates. Twenty different pulsotypes were distinguished and 16 out of the 29 isolates were classified into seven clusters. A total of 16 virulence types (VTs) were identified. Five VTs accounted for 45% of the total cases and coincided with those of previously described Epidemic Clones (ECs) of L. monocytogenes.

Trends in US Hospital Stays for Listeriosis in Infants

BACKGROUND AND OBJECTIVES

Although listeriosis is rare in infants, it is common for young infants with suspected serious bacterial infection to be treated empirically with agents selected, in part, for their activity against Listeria monocytogenes. Our objectives were to describe the recent epidemiology of hospital discharges for listeriosis among infants in the United States and to precisely estimate the incidence of listeriosis according to infant age and meningitis status.

METHODS

We generated national estimates for listeriosis discharges in each of the 6 years for which samples were available in the Kids' Inpatient Database during the period 1997-2012. We used random-effects models to pool descriptive information and population rates across study years.

RESULTS

The cumulative number of US hospital discharges for listeriosis in infants was 344 (95% confidence interval [CI]: 290-397) over the 6 study years. The pooled annual incidence rate in infants (per 100,000 births) was 1.41 (95% CI: 1.01-1.80) after accounting for marked fluctuation in annual rates (range: 0.66-1.86; I2=79.3%). Discharges for listeriosis without meningitis were particularly rare after the first week of life. Our models predicted only 2.7 (95% CI: 1.1-4.2) and 1.8 (95% CI: 0.0-3.6) such discharges per year in infants admitted at ages 7 to 28 days and 29 to 364 days, respectively.

CONCLUSIONS

From the perspective of providing coverage against listeriosis, the routine practice of including ampicillin in the empirical treatment of febrile infants should be reevaluated for those older than 1 week without clinical evidence of meningitis.

The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults

Bacterial meningitis and meningococcal sepsis are rare conditions with high case fatality rates. Early recognition and prompt treatment saves lives. In 1999 the British Infection Society produced a consensus statement for the management of immunocompetent adults with meningitis and meningococcal sepsis. Since 1999 there have been many changes. We therefore set out to produce revised guidelines which provide a standardised evidence-based approach to the management of acute community acquired meningitis and meningococcal sepsis in adults. A working party consisting of infectious diseases physicians, neurologists, acute physicians, intensivists, microbiologists, public health experts and patient group representatives was formed. Key questions were identified and the literature reviewed. All recommendations were graded and agreed upon by the working party. The guidelines, which for the first time include viral meningitis, are written in accordance with the AGREE 2 tool and recommendations graded according to the GRADE system. Main changes from the original statement include the indications for pre-hospital antibiotics, timing of the lumbar puncture and the indications for neuroimaging. The list of investigations has been updated and more emphasis is placed on molecular diagnosis. Approaches to both antibiotic and steroid therapy have been revised. Several recommendations have been given regarding the follow-up of patients.

Genetic and phenotypic characterization of Listeria monocytogenes from human clinical cases that occurred in Portugal between 2008 and 2012

Listeria monocytogenes infection (listeriosis) is an uncommon but severe foodborne illness that affects mainly individuals with recognized underlying conditions: the elderly, immunocompromised individuals, and pregnant women and their fetuses. The aim of this study was to obtain epidemiological data on cases of listeriosis occurring in Portugal from 2008 through 2012, collected in hospitals on a voluntary basis. L. monocytogenes isolates were characterized by genoserotyping by multiplex polymerase chain reaction, DNA macrorestriction pulsed-field gel electrophoresis (PFGE), and determination of minimal inhibitory concentration (MIC, μg/mL) for 12 antibiotics. During this period, 203 cases of listeriosis were detected. The annual incidence rate observed ranged from 0.2 to 0.7 cases per 100,000 inhabitants. Nineteen cases (9.5%) corresponded to maternal/neonatal (MN) infections. The mean age of the nonmaternal/neonatal (non-MN) cases with documented age was 59 years, and 46.4% occurred in patients aged over 65 years. The majority of listeriosis cases were caused by genoserogroup IVb isolates, and PFGE analysis revealed a high molecular diversity, suggesting that most were sporadic. Nevertheless, several clusters of isolates presenting different geographic and time distributions were detected. The incidence of antibiotic-resistant isolates of L. monocytogenes was low but significantly higher than in previous years (2003-2007). The implementation of a national surveillance system monitoring the incidence of listeriosis and antimicrobial resistance of strains would be most valuable, allowing identification of sporadic and outbreak cases, to detect general trends in antibiotic susceptibilities, and potentially identify food sources of clinical strains.

Pregnancy-related listeriosis in France, 1984 to 2011, with a focus on 606 cases from 1999 to 2011

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What information do Dutch midwives give clients about toxoplasmosis, listeriosis and cytomegalovirus prevention? An exploratory study of videotaped consultations

OBJECTIVE

To assess information provided by midwives about methods to prevent toxoplasmosis, listeriosis and cytomegalovirus, and whether the amount of provided information varied according to clients' and midwives' characteristics.

METHODS

Intake consultations with 229 clients in four midwifery practices were videotaped between August 2010 and April 2011. Videotaped intake consultations, where infectious disease prevention were discussed, were evaluated, using a specifically designed nine-item scoring tool. Midwives and clients filled in a questionnaire about their background characteristics. Multilevel linear regression analysis was performed to establish associations between the amount of information provided and clients' and midwives' characteristics.

RESULTS

In total 172 consultations with fifteen midwives were suitable for analyses. Information about not eating raw or undercooked meat and not consuming unpasteurized dairy products was provided most often. Information about not sharing eating utensils with small children and thoroughly reheating all ready-to-eat foods were rarely provided. More information was provided when the client was a primigravidae or the consultation lasted longer than 50min.

CONCLUSION

Information on infectious disease prevention given to pregnant women by primary care midwives was insufficient; especially for cytomegalovirus prevention.

PRACTICE IMPLICATIONS

A guideline for professionals on preventable infectious diseases may be useful to inform pregnant women properly.

Human isolates ofListeria monocytogenesin Sweden during half a century (1958–2010)

Isolates ofListeria monocytogenes(n = 932) isolated in Sweden during 1958–2010 from human patients with invasive listeriosis were characterized by serotyping and pulsed-field gel electrophoresis (PFGE) (AscI). Of the 932 isolates, 183 different PFGE types were identified, of which 83 were each represented by only one isolate. In all, 483 serovar 1/2a isolates were distributed over 114 PFGE types; 90 serovar 1/2b isolates gave 32 PFGE types; 21 serovar 1/2c isolates gave nine PFGE types; three serovar 3b isolates gave one PFGE type; and, 335 serovar 4b isolates gave 31 PFGE types. During the 1980s in Sweden, several serovar 4b cases were associated with the consumption of European raw soft cheese. However, as cheese-production hygiene has improved, the number of 4b cases has decreased. Since 1996, serovar 1/2a has been the dominantL. monocytogenesserovar in human listeriosis in Sweden. Therefore, based on current serovars and PFGE types, an association between human cases of listeriosis and the consumption of vacuum-packed gravad and cold-smoked salmon is suggested.

Observational study to assess pregnant women's knowledge and behaviour to prevent toxoplasmosis, listeriosis and cytomegalovirus

Background

Toxoplasmosis, listeriosis and cytomegalovirus (CMV) can negatively affect pregnancy outcomes, but can be prevented by simple precautions of pregnant women. Literature suggests that pregnant women are not always adequately informed by their care provider about preventable infectious diseases and most pregnant women have a low level of knowledge regarding these topics. There is not much information about the actual risk behaviour of pregnant women. The purpose of this study was to assess knowledge and risk behaviour related to toxoplasmosis, listeriosis and CMV infection prevention in pregnant women.

Methods

A cross-sectional survey among pregnant women from twenty midwifery practices across the Netherlands that participated in the DELIVER study, between October 2010 and December 2010. The questionnaire items covered respondents’ knowledge of preventive practices in general, risk behaviour, and sources of received information.

Results

Of the 1,097 respondents (response 66.0%), 75.3% had heard, read or seen information about toxoplasmosis, 61.7% about listeriosis and 12.5% about CMV. The majority reported having heard about these infections from their care providers or read about these in printed media or on the Internet. Respondents showed limited knowledge about preventive practices for toxoplasmosis, listeriosis or CMV infection. Regarding toxoplasmosis, risk behaviour was more prevalent among respondents who had a high level of education, had the Dutch nationality, did not take folic acid during their first trimester, and had ever worked in a children day-care setting. Regarding listeriosis, risk behaviour was more prevalent among respondents who where in their third trimester. Regarding CMV infections, risk behaviour was less prevalent among respondents who were in their third trimester of pregnancy.

Conclusion

Of the respondents, a substantial part did not have knowledge about preventive practices to avoid listeriosis, toxoplasmosis and CMV infections during pregnancy. Many pregnant women are appropriately avoiding risk behaviour, without knowing what they are avoiding. Advising pregnant women about behaviours and life-style habits to prevent infectious diseases remains important and information about preventive practices need to be complete and adequate. However, it may be less important to give pregnant women specific infectious diseases information. More attention towards CMV is necessary.

Systemic lupus erythematosus (SLE) cerebritis versus Listeria monocytogenes meningoencephalitis in a patient with systemic lupus erythematosus on chronic corticosteroid therapy: the diagnostic importance of cerebrospinal fluid (CSF) of lactic acid levels

BACKGROUND

Listeria monocytogenes is a motile, aerobic, Gram-positive intracellular bacillus that causes enteritis, meningitis, meningoencephalitis, or subacute bacterial endocarditis. Patients with impaired T-lymphocyte function/cell-mediated immunity are predisposed to intracellular pathogens, e.g., L. monocytogenes. In adults, infection by L. monocytogenes of the central nervous system (CNS) clinically manifests as either acute bacterial meningitis or meningoencephalitis. In patients with systemic lupus erythematosus (SLE) presenting with headache and fever, SLE cerebritis must be differentiated from acute bacterial meningitis by lumbar puncture and cerebrospinal fluid (CSF) analysis. Neuropathogenic viruses are the most common causes of meningoencephalitis. The most rapid and accurate way to differentiate bacterial meningoencephalitis from nonbacterial meningoencephalitis is CSF lactic acid levels.

METHODS

We present a patient receiving chronic corticosteroid therapy and manifesting SLE and severe L. monocytogenes meningoencephalitis. An early diagnosis of L. meningoencephalitis was achieved by demonstrating a very highly elevated level of lactic acid in his CSF, days before CSF and blood cultures tested positive for L. monocytogenes.

RESULTS AND CONCLUSION

In this patient, the highly elevated levels of lactic acid in his CSF ruled out both viral meningoencephalitis and SLE cerebritis. The case was complicated by communicating hydrocephalus, and the patient later underwent placement of a shunt. He completed 6 weeks of meningeal dosed ampicillin.

Listeria meningitis and ventriculitis in an immunocompetent child: case report and literature review

Listeria monocytogenes meningitis is very rare in immunocompetent children. We present a case of a previously healthy 6-year-old girl who developed L. monocytogenes meningitis and ventriculitis. We also review the medical literature on non-neonatal L. monocytogenes meningitis in immunocompetent children.

A multifactorial risk prioritization framework for foodborne pathogens

We develop a prioritization framework for foodborne risks that considers public health impact as well as three other factors (market impact, consumer risk acceptance and perception, and social sensitivity). Canadian case studies are presented for six pathogen-food combinations: Campylobacter spp. in chicken; Salmonella spp. in chicken and spinach; Escherichia coli O157 in spinach and beef; and Listeria monocytogenes in ready-to-eat meats. Public health impact is measured by disability-adjusted life years and the cost of illness. Market impact is quantified by the economic importance of the domestic market. Likert-type scales are used to capture consumer perception and acceptance of risk and social sensitivity to impacts on vulnerable consumer groups and industries. Risk ranking is facilitated through the development of a knowledge database presented in the format of info cards and the use of multicriteria decision analysis (MCDA) to aggregate the four factors. Three scenarios representing different stakeholders illustrate the use of MCDA to arrive at rankings of pathogen-food combinations that reflect different criteria weights. The framework provides a flexible instrument to support policymakers in complex risk prioritization decision making when different stakeholder groups are involved and when multiple pathogen-food combinations are compared.

Surveillance for Listeria monocytogenes and listeriosis, 1995-2004

Canadian cases and outbreaks of illness caused by Listeria monocytogenes between 1995 and 2004 were assessed. Isolates (722 total) were characterized by serotyping, and pulsed-field gel electrophoresis (PFGE) was performed to provide a means of detecting case clusters. Rates of listeriosis remained fairly consistent during the period of study, and patient characteristics were similar to those seen in studies of other populations. Most isolates were obtained from blood and cerebrospinal fluid, although during some outbreak investigations isolates were also obtained from stools. Serotype 1/2a predominated in isolates from patients in Canada, followed by serotypes 4b and 1/2b. Outbreaks caused by L. monocytogenes that occurred during the period of study were caused by isolates with serotypes 1/2a and 4b. A retrospective analysis of PFGE data uncovered several clusters that might have represented undetected outbreaks, suggesting that comprehensive prospective PFGE analysis coupled with prompt epidemiological investigations might lead to improved outbreak detection and control.

A survey of laboratory-confirmed isolates of invasive listeriosis in Israel, 1997–2007

During the 11-year period from 1997 to 2007, 321 isolates ofListeria monocytogenesfrom sporadic cases of invasive listeriosis were reported to the national reference laboratory in Israel. Of these isolates, 113 (35%) were identified from perinatal cases, and 208 (65%) from non-perinatal cases. The prevalent serovars were 4b, 1/2b, 1/2a and 4c. Serovar 4b was identified in 80·5% of the perinatal isolates (P=0·0162), while the number of 1/2b and 1/2a strains increased in the ⩾60 years old group (P=0·0285). Resistance to tetracycline was found in eight 4b isolates. The seasonal distribution showed that 206 isolates (64·2%) were submitted during the hot season (May–October). The estimated morbidity for the study period was 4·4 per million. The incidence of invasive listeriosis was higher in the perinatal group (5·6/100 000), than in individuals aged ⩾60 years (1·5/100 000).

Activity of daptomycin against Listeria monocytogenes isolates from cerebrospinal fluid

We tested the activity of daptomycin against 76 Listeria monocytogenes isolates from cerebrospinal fluid by broth dilution and Etest methods. For the broth dilution method, the MIC range was 1.0 to 8.0 and the MIC at which 90% of the isolates tested were inhibited (MIC(90)) was 4.0 mg/liter. For the Etest method, the MIC range was 1.0 to 4.0 and the MIC(90) was 4.0 mg/liter. Presently, daptomycin cannot be recommended for the treatment of L. monocytogenes meningitis.

Listeria prevalence and Listeria monocytogenes serovar diversity at cull cow and bull processing plants in the United States

Listeria monocytogenes, the causative agent of epidemic and sporadic listeriosis, is routinely isolated from many sources, including cattle, yet information on the prevalence of Listeria in beef processing plants in the United States is minimal. From July 2005 through April 2006, four commercial cow and bull processing plants were sampled in the United States to determine the prevalence of Listeria and the serovar diversity of L. monocytogenes. Samples were collected during the summer, fall, winter, and spring. Listeria prevalence on hides was consistently higher during cooler weather (28 to 92% of samples) than during warmer weather (6 and 77% of samples). The Listeria prevalence data collected from preevisceration carcass ranged from undetectable in some warm season samples to as high as 71% during cooler weather. Listeria on postintervention carcasses in the chill cooler was normally undetectable, with the exception of summer and spring samples from one plant where > 19% of the carcasses were positive for Listeria. On hides, L. monocytogenes serovar 1/2a was the predominant serovar observed, with serovars 1/2b and 4b present 2.5 times less often and serovar 1/2c not detected on any hides sampled. L. monocytogenes serovars 1/2a, 1/2c, and 4b were found on postintervention carcasses. This prevalence study demonstrates that Listeria species are more prevalent on hides during the winter and spring and that interventions being used in cow and bull processing plants appear to be effective in reducing or eliminating Listeria contamination on carcasses.