Listeriosis in pregnancy: under-diagnosis despite over-treatment

Listeria in Pregnancy-The Forgotten Culprit

Listeria monocytogenes is a Gram-positive bacterium that causes listeriosis, a severe foodborne illness that is particularly dangerous during pregnancy. It thrives in diverse environments, including refrigerated conditions and food production facilities, due to its adaptability to varying temperatures, pH levels, and salt concentrations. Its virulence stems from the ability to invade host cells, particularly macrophages and epithelial cells, and avoid, or at least postpone, immune detection by utilizing virulence factors such as internalins, listeriolysin O, and actin assembly-inducing protein. This intracellular motility and biofilm formation make LM a persistent pathogen in food safety and public health. Pregnant women are at a much higher risk of listeriosis, which can result in serious fetal complications such as miscarriage, stillbirth, and preterm labor due to LM's affinity for placental tissues. The vertical transmission of LM from mother to fetus can lead to neonatal listeriosis, which can result in sepsis and meningitis, with high mortality rates if not promptly treated. Early diagnosis and treatment with antibiotics, such as ampicillin or gentamicin, are crucial for maternal and neonatal outcomes.

Clinical and microbiological characteristics and follow-up of invasive Listeria monocytogenes infection among hospitalized patients: real-world experience of 16 years from Hungary

PURPOSE

Invasive Listeria monocytogenes infection is rare, but can lead to life-threatening complications among high-risk patients. Our aim was to assess characteristics and follow-up of adults hospitalized with invasive L. monocytogenes infection.

METHODS

A retrospective observational cohort study was conducted at a national referral center between 2004 and 2019. Patients with proven invasive listeriosis, defined by the European Centre for Disease Prevention and Control criteria, were included. Data collection and follow-up were performed using the hospital electronic system, up until the last documented visit. The primary outcome was in-hospital all-cause mortality, secondary outcomes included residual neurological symptoms, brain abscess occurrence, and requirement for intensive care unit (ICU) admission.

RESULTS

Altogether, 63 cases were identified (57.1% male, median age 58.8 ± 21.7 years), and 28/63 developed a complicated disease course (44.4%). At diagnosis, 38/63 (60.3%) presented with sepsis, 54/63 (85.7%) had central nervous system involvement, while 9/63 (14.3%) presented with isolated bacteremia. Frequent clinical symptoms included fever (53/63, 84.1%), altered mental state (49/63, 77.8%), with immunocompromised conditions apparent in 56/63 (88.9%). L. monocytogenes was isolated from blood (37/54, 68.5%) and cerebrospinal fluid (48/55, 87.3%), showing in vitro full susceptibility to ampicillin and meropenem (100% each), gentamicin (86.0%) and trimethoprim/sulfamethoxazole (97.7%). In-hospital all-cause mortality was 17/63 (27.0%), and ICU admission was required in 28/63 (44.4%). At discharge, residual neurological deficits (11/46, 23.9%) and brain abscess formation (6/46, 13.0%) were common.

CONCLUSION

Among hospitalized adult patients with comorbidities, invasive L. monocytogenes infections are associated with high mortality and neurological complications during follow-up.

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.

Clinical Features and Antibiotic Treatment of Neonatal Listeriosis: A Hospital-Based Study

Purpose

To determine the clinical features, laboratory findings, antibiotic treatment, and outcomes of neonatal listeriosis in a specialized tertiary hospital in Wuhan, China.

Patients and Methods

We retrospectively analyzed the medical records of patients diagnosed with neonatal listeriosis at Maternal and Child Health Hospital of Hubei Province from January 2015 to December 2022. Listeriosis was indicated by positive culture for Listeria monocytogenes (LM).

Results

A total of 11 cases were included in our study. The incidence rate of neonatal listeriosis was 2.06 per 100,000 live births. Seventy-three percent of the cases were born prematurely, caused early onset sepsis. Respiratory distress (100%) was the most common and earliest symptom, followed by fever (64%) and rashes (27%). The levels of C-reactive protein (CRP) and procalcitonin (PCT) were elevated in 100% of the cases. The median time-to-positivity (TTP) of the culture was 15 hours (range 9-28hours). Of the 11 neonates, 6 were cured, 2 showed improvement, and 3 died, with a mortality rate of 27%. There were statistically significant differences in Apgar score at 5 minutes (p=0.037) and CRP (p=0.025) between the survival group and fatality group. Ampicillin was sensitive to LM isolates and effective for therapy if initiated early.

Conclusion

Neonatal listeriosis is a rare but severe infection with a high mortality rate. Early identification and appropriate use of effective antibiotics are particularly critical for achieving positive outcomes. Apgar score and CRP are relevant indices for prognosis. Ampicillin is the first-line therapy and can be empirically administered to neonates suspected of having listeriosis.

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.

Presentation and outcomes of Listeria-affected pregnancies in Johannesburg tertiary hospitals: A 2-year review

OBJECTIVE

To describe maternal risk factors, presentations, peripartum findings, and pregnancy outcomes in Listeria monocytogenes-infected women.

METHODS

A retrospective descriptive case review. The records of 51 pregnant women infected with listeriosis who delivered infants between February 1, 2016 and February 28, 2018 at three academic hospitals in Johannesburg, South Africa, were included. The diagnosis of listeriosis was made on maternal/neonatal-sampled blood or tissue cultures.

RESULTS

Forty-eight (82.3%) Listeria infections of maternal and neonatal listeriosis were diagnosed on blood culture. The median gestational age at diagnosis was at a preterm gestation of 33 (20-43) weeks. Twenty-eight women (54.9%) had normal vaginal deliveries. Precipitous labor was described in 18 (39%) of these women. Fetal distress was the indication for cesarean section in 22 (41.2%) women. Meconium-stained amniotic fluid was found in 21 (61.7%) women at the time of delivery. The category of very low birth weight had 14 (27.4%) neonates with an Apgar score of less than 7 at 5 min. Maternal morbidities included chorioamnionitis (3 [5.8%]) and puerperal infections (7 [13.7%]). The HIV-positive anemic women had a tendency towards listerial infections.

CONCLUSIONS

Symptoms of listeriosis were non-specific and diagnosis was detected on blood culture sampling. Risk factors included HIV seropositivity and were associated with puerperal infections and anemia.

Maternal and obstetric outcomes of listeria pregnancy: insights from a national cohort

OBJECTIVE

We sought to evaluate and describe the maternal and obstetric morbidity associated with Listeria infection in pregnancy.

METHODS

Retrospective cohort of pregnant women using the 2007-2018 National Inpatient Sample. Pregnant women with discharge diagnosis codes consistent with Listeria infection were identified. Outcomes of deliveries complicated by Listeria infection were compared to those of delivery without this infection. The primary outcome was a composite of severe maternal morbidity. Secondary outcomes included components of the composite, maternal length of stay, mode of delivery, stillbirth, and preterm delivery.

RESULTS

We identified 134 maternity associated hospitalizations for Listeria (weighted national estimate 666), of which 72 (weighted national estimate of 358) were delivery admissions. Delivery admissions complicated by Listeria resulted in higher rates of severe maternal morbidity than those without, (30.9% vs. 1.6%, p<.001). In adjusted analyses, women with Listeria had 21.2-fold higher risk of severe maternal morbidity (95% CI: 14.0, 31.9) when compared to those without Listeria. Specifically, Listeria delivery admissions had higher rates of acute respiratory distress syndrome (2.8% vs. 0.1%, p<.001), mechanical ventilation (1.4% vs. 0.0%, p<.001), sepsis (28.1% vs. 0.1%, p<.001), and shock (1.4% vs. 0.0%, p<.001). Listeria delivery admissions also had higher rates of preterm birth (61.3% vs. 7.7%, p < 0.001) and stillbirth (13.5% vs. 0.7%, p<.001). Women hospitalized or delivered with Listeria infection were also more likely to have a cesarean delivery (57.9% vs. 32.9, p<.001) and the average length of stay for women with Listeria was also longer (4.0 days vs. 2.3 days, p<.001).

CONCLUSIONS

Women with Listeria infection in pregnancy have higher rates of severe maternal morbidity, specifically increased risk of sepsis, septic shock, and acute respiratory distress syndrome. Among delivery hospitalizations, these women also have higher rates of preterm birth and stillbirth.

Fetal sepsis: a cause of stillbirth

Infection is considered a leading cause of fetal death, responsible for approximately 20% of cases. Such estimates are derived from the frequency of acute histological chorioamnionitis and funisitis in cases of fetal death rather than direct detection of microorganisms in the fetal compartment. We report a case of clinically unexplained fetal death at 38 weeks of gestation in an uncomplicated pregnancy resulting in delivery of an appropriate-for-gestational-age fetus. The mother did not have any clinical signs of infection. Overwhelming bacterial invasion in multiple fetal organs, including the heart, liver, spleen, and kidneys, was observed despite the lack of evidence of maternal clinical infection. The bacteria were visualized by using standard histologic techniques (e.g. H&E/ tissue Gram stain) highlighting the value of autopsy in determining the cause of death.

A comprehensive analysis of listeriosis in 13 pregnant women and 27 newborns in Xi'an from 2011 to 2020

BACKGROUND

Listeriosis is a severe foodborne infection associated with high mortality. Pregnant women and newborns are at a particularly high risk of infection. However, the data on epidemiology of maternal-neonatal listeriosis in Xi'an are little known. The aim of this study was to investigate the epidemiological and clinical features of maternal-neonatal listeriosis in Xi'an.

METHODS

A total of 40 cases of listeriosis confirmed by positive cultures [blood or cerebrospinal fluid (CSF)] and admitted to the Northwest Women's and Children's Hospital (NWCH) from 2011 to 2020 were enrolled. Data from all patients were collected from the hospital's electronic medical records. Data analysis and epidemiological investigation were carried out by demographic information, time of onset, clinical and laboratory characteristics. Descriptive statistical indicators were obtained using SPSS21.0 and were expressed as median, mean, standard deviation and interquartile range.

RESULTS

The incidence of maternal and neonatal listeriosis in NWCH over the last decade was 5/100,000 and 10.4/100,000 respectively and Listeriosis was more likely to occur in spring and summer. The most common symptom was as follows: (I) maternal: fever (85%), abdominal pain (77%), vaginal fluid or colporrhagia (46%); (II) neonatal: respiratory distress (52%), fever (33%). Laboratary results were as follows: (I) maternal: elevated C-reactive protein (CRP) (100%), white blood cells (WBC) or neutrophil (NEUT#) (85%), and monocyte counts (MONO#) (77%); (II) neonatal: increased WBC (81%), MONO# (81%), CRP (78%), NEUT# and lymphocytes (73%); and elevated protein (PRO) (95%) and WBC count (86%) in CSF while decreased in glucose (GLU) (73%). Compared to neonatal group, the ratio of neutrophils to lymphocytes in maternal group raise to a higher level (92% to 42%). The outcomes of maternal were favorable and 54% of them suffered acute chorioamnionitism. Yet neonatal deaths account for up to 33%.

CONCLUSIONS

Listeriosis is a rare disease with extremely variable clinical characteristics in Xi'an. Our data indicated that unexplained fever, abdominal pain, signs of premature and respiratory symptoms accompanied by a progressive increase in WBC, CRP, NEUT#, MONO# even include WBC and PRO in CSF while GLU decreased, the possibility of an LM infection should be considered.

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.

Listeria infection in young infants: results from a national surveillance study in the UK and Ireland

OBJECTIVES

To describe the epidemiology, age at infection, clinical characteristics and outcome of listeria infection in young infants to inform management and empiric antibiotic choice in young infants.

DESIGN

Prospective 2-year surveillance of Listeria monocytogenes infection in young infants detected through the British Paediatric Surveillance Unit 'orange card' system and triangulated with the public health laboratories.

SETTING

National population study (England, Wales, Scotland and the Ireland) PATIENTS: All infants under 90 days with proven or probable invasive listeriosis MAIN OUTCOME MEASURES: Incidence, mortality, age of infection, clinical characteristics and outcome RESULTS: During a 2-year period (2017-2019), 27 cases of listeriosis in infants <90 days of age were reported. The incidence of listeriosis in this study was 1.8 per 100 000 live births with 7% mortality (2/27). Nearly all cases presented within the first 24 hours of life (26/27). The majority (20/27, 74%) were born preterm and 16/24 (67%) were born to women from ethnic minority backgrounds.

CONCLUSIONS

Invasive listeriosis in young infants in the UK and Ireland is rare and presents early in the neonatal period. National guidelines that recommend the use of amoxicillin as part of empiric regimes for sepsis and meningitis in infants over 1 month of age should be modified.

Seroprevalence of Listeria monocytogenes in HIV infected pregnant women from Brazil

Objective

To describe the prevalence and factors associated with serologic response to Listeria monocytogenes in HIV infected and uninfected pregnant women in Brazil.

Methods

Cross-sectional study, pregnant women after 14 weeks of gestational age were enrolled. Positive serologic test for L. monocytogenes was defined as titers >1:80 (agglutination test). Comparisons were performed using logistic regression.

Results

A total of 213 women were enrolled, 73 (34%) were HIV infected. 55 women were seroreactive for L. monocytogenes, 27 (37%) HIV-infected and 28 (20%) HIV-uninfected (p < 0.01). Considering the diet record, white cheese consumption was associated with seroreactivity (p < 0.01). In the group of pregnant women living with HIV, the variables associated with L. monocytogenes positive serology were: lower CD4+ cells count at study entry OR=4.8 (95%CI=1.1–19.8) and having neonates admitted to the intensive care unit OR=5.9 (95%CI=1.01–34.9).

Conclusion

Positive serology for Listeria monocytogenes was associated with HIV infection. Brazilian women should avoid white cheese during pregnancy.

Pregnancy Complicated by Listeria Monocytogenes: A Case Report and Review of the Literature

Listeria Monocytogenes, a small facultative anaerobic, gram positive, motile bacillus is a rare, but consequential etiologic agent of food borne illness which inordinately impacts immunocompromised individuals. The organism infects many types of animals and contaminates a multitude of foodstuffs such as milk, chicken, beef and vegetables. This microbe additionally has a distinct proclivity to infect the maternal-fetoplacental unit with resultant adverse perinatal outcomes inclusive of spontaneous abortion, preterm delivery, chorioamnionitis, neonatal meningitis and death. We present a case of Listeriosis complicating pregnancy with a subsequent comprehensive review of the literature.

Listeriosis in Pregnancy: A Review

Importance

Listeriosis is a rare foodborne condition that can cause serious health consequences in neonates and pregnant women. Listeria monocytogenes can be vertically transmitted to the fetus, resulting in adverse maternal, fetal, and neonatal outcomes. In this review, we summarize what is currently known about listeriosis in pregnancy and review the current management and treatment recommendations.

Objective

To summarize the clinical and relevant evidence available regarding listeriosis in pregnancy and educate providers on common clinical symptoms, sequelae, and appropriate treatment guidelines.

Evidence Acquisition

A PubMed review was conducted using search terms "pregnancy" OR "Listeria" OR "Maternal Listeriosis," and "Neonatal Listeriosis." The search included review articles, original research articles, and guidelines on diagnosis and management of listeriosis in pregnancy. The search was limited to the English language and publications between 1988 and July 2018.

Conclusions

Listeriosis in pregnancy can result in severe adverse maternal, fetal, and neonatal outcomes including miscarriage, preterm labor, fetal death, and neonatal meningitis and sepsis. Early treatment has been shown to improve fetal and neonatal outcomes; therefore, prevention with education and early diagnosis prompting treatment will improve overall outcomes.

Relevance

The incidence of listeriosis is expected to rise in the coming years due to changes in the US population, with increasing numbers of older Americans and Hispanic individuals, both of whom are at higher risk. Pregnant women contract listeriosis at a rate that is 16- to 18-fold greater than the general population. Given the expected increased rise in incidence and increased susceptibility of pregnant women, understanding the common clinical symptoms, maternal and fetal sequelae, and appropriate treatment guidelines is essential.

Sequelae of Fetal Infection in a Non-human Primate Model of Listeriosis

Listeria monocytogenes (Lm) is a common environmental bacterium that thrives on vegetation and soil matter, but can infect humans if contaminated food products are ingested, resulting in severe disease in immunosuppressed populations, including pregnant women and newborns. To better understand how the unique immunological milieu of pregnancy increases susceptibility to infection, we study listeriosis in cynomolgus macaques, a non-human primate that closely resembles humans in placentation and in the physiology, and immunology of pregnancy. Non-human primates are naturally susceptible to Lm infection, and spontaneous abortions due to listeriosis are known to occur in outdoor macaque colonies, making them ideal models to understand the disease pathogenesis and host-pathogen relationship of listeriosis. We have previously shown that Lm infection in the first trimester has a high rate of miscarriage. This study expands on our previous findings by assessing how the quantity of Lm as well as stage of pregnancy at the time of exposure may influence disease susceptibility. In the current study we inoculated a cohort of macaques with a lower dose of Lm than our previous study and although this did not result in fetal demise, there was evidence of in utero inflammation and fetal distress. Animals that were reinfected with an equivalent or higher dose of the same strain of Lm resulted in approximately half of cases continuing to term and half ending in fetal demise. These cases had inconsistent bacterial colonization of the fetal compartment, suggesting that Lm does not need to directly infect the placenta to cause adverse pregnancy outcomes. Timed surgical collection of tissues following inoculation demonstrated that transmission from mother to fetus can occur as soon as 5 days post-inoculation. Lastly, third trimester inoculation resulted in pregnancy loss in 3 out of 4 macaques, accompanied by characteristic pathology and Lm colonization. Collectively, our studies demonstrate that common laboratory culture tests may not always recover Lm despite known maternal ingestion. Notably, we also find it is possible for maternal infection to resolve in some cases with no discernible adverse outcome; however, such cases had evidence of a sterile intrauterine inflammatory response, with unknown consequences for fetal development.

Clinical features of neonatal listeriosis in Taiwan: A hospital-based study

BACKGROUND

Neonatal listeriosis is a major cause of mortality in newborn; however, there is limited information about this disease in Taiwan. The aim of our study was to identify the outcome determinants, clinical features, and incidence of pregnancy-associated listeriosis, which includes both neonatal and maternal listeriosis.

METHODS

We retrospectively analyzed the medical records of neonatal and maternal patients with pregnancy-associated listeriosis at two hospitals in Taiwan from January 2000 to December 2018. Listeriosis was indicated by positive Listeria monocytogenes culture.

RESULTS

Our study examined 18 neonates and 19 mothers. The neonatal and fetal death rate was 24%. All five cases of fetal losses or neonatal deaths occurred before 29 weeks of gestational age. The annual incidence of confirmed neonatal listeriosis increased significantly from 0.94/10,000 neonatal inpatients in 2000-2011 to 5.45/10,000 neonatal inpatients in 2012-2018 (p = 0.026). Clinical presentations of neonatal listeriosis included respiratory distress (85%), leukocytosis or leukopenia (77%), bandemia (69%), thrombocytopenia (77%), hypocalcemia (100%) and elevated C-reactive protein (CRP) levels (92%). Lower gestation correlated with a higher fatality rate (p = 0.002). Among the maternal cases investigated, 67% had a diagnosis of listeriosis, and 72% presented with fever. However, only 21% of the 19 mothers received complete antepartum ampicillin treatment.

CONCLUSIONS

The incidence of neonatal listeriosis is increasing, especially in preterm neonates. Maternal listeriosis should be adequately treated with appropriate empirical antibiotics.

Systemic Listeria monocytogenes Infection as a Model to Study T Helper Cell Immune Responses

Listeria monocytogenes, a Gram-positive facultative intracellular pathogen, has been widely used as a model for studying the immune response. Here, we describe a protocol for the systemic infection of mice with L. monocytogenes, followed by isolation of lymphocytes from spleens and lymph nodes. We also include details on how to culture and store L. monocytogenes, as well as the specifics for fluorescence-activated cell sorting (FACS) for CD4⁺ cells in response to the systemic infection. This protocol can be adapted by changing the dosage of L. monocytogenes for a more or less aggressive infection and/or sorting for other immune cell subtypes of interest.