Listeria monocytogenes is recognized as a significant foodborne pathogen, capable of causing listeriosis in humans, which is a global public health concern. This pathogen is particularly dangerous for pregnant women, as it can lead to invasive listeriosis in fetuses and neonates, posing a significant threat to both maternal and fetal health. Therefore, establishing suitable in vitro and in vivo models for L. monocytogenes placenta infection, as well as analyzing and exploring the infection process and its pathogenic mechanism, are important approaches to prevent and control L. monocytogenes infection in mothers and infants. In this study, we reviewed the in vitro and in vivo placental models used for studying the infection of L. monocytogenes in maternal and infant, summarized and discussed the advantages and limitations of each model, and explored the potential of in vitro cell models and organoids for the study of L. monocytogenes infection. This paper aims to support the study of the infection pathway and pathogenesis of listeriosis and provide scientific references for the prevention and control of L. monocytogenes infection.
Female ; Humans ; Pregnancy ; Listeria monocytogenes ; Listeriosis/prevention & control* ; Placenta/pathology* ; Public Health ; Infant, Newborn

OBJECTIVES: To investigate the clinical characteristics of patients with listeriosis and to provide a basis for diagnosis, treatment, prevention and control of hospital infection. METHODS: A total of 10 inpatients, who suffered from the listeriosis in Xiangya Hospital, Central South University from January 2013 to June 2019, were retrospectively collected for this study. The characteristics of the patients' age, gander, basic information, case type, clinical manifestations, first consultation department, days of diagnosis, infection indicator, specimen type, results of drug sensitivity, treatment plan, hospital infection or not, outcome, follow-up data were analyzed. RESULTS: Two cases were pregnant women and other were non-pregnant adults among 10 patients with listeriosis. Among them, there were 3 cases with hospital acquired infection. The age of patient onset was 27-71 years old, and the time from onset to diagnosis was 5-36 days. Five cases had fever, and other 5 cases had not fever. There were headache, fatigue, local pain, and other specialized symptoms in the 10 patients.The white blood cell count,the neutrophil ratio, the inflammatory index C-reactive protein, the procalcitonin were all increased, and the erythrocyte sedimentation was accelerated in the 10 patients.All the patients were sensitive to ampicillin, penicillin G, meropenem, and compound sinomine. CONCLUSIONS Listeriosis often affects the patients with low immunity, which often leads to misdiagnosis or missed diagnosis in clinic.So early prevention, early diagnosis, and early treatment can reduce mortality; it is important for departments of nosocomial infection management to manage patients' diet for avoiding outbreaks of listeriosis in hospital.
Adult ; Aged ; Female ; Humans ; Listeria monocytogenes ; Listeriosis/epidemiology* ; Meropenem ; Middle Aged ; Pregnancy ; Pregnancy Complications, Infectious ; Retrospective Studies

Listeria monocytogenes (Lm) is zoonotic pathogen that can cause listeriosis, and vaccine is one of the effective methods to prevent this pathogen infection. In this study, we developed a novel vaccine that is a mixture of inactivated bacteria and Montanide™ ISA 61 VG, a mineral oil adjuvant, and evaluated the safety and immune response characteristics of this vaccine. The mice immunized with the ISA 61 VG adjuvant had high safety, and it could induce significantly higher titer of anti-listeriolysin O (LLO) antibody and higher value of IgG2a/IgG1 ratio compared with the group without the adjuvant. In particular, it could provide 100% immune protection against lethal doses of Lm challenge in mice. In summary, ISA 61VG adjuvant significantly enhanced the ability of inactivated listeria vaccine to induce humoral and cellular immune responses, thereby enhanced the protective immune response in the host, and it is a potential vaccine candidate for the prevention of Lm infection in humans and animals.
Adjuvants, Immunologic ; pharmacology ; Animals ; Hemolysin Proteins ; immunology ; pharmacology ; Immunity, Cellular ; drug effects ; Listeria monocytogenes ; immunology ; Listeriosis ; prevention & control ; Mice ; Mice, Inbred BALB C ; Vaccines, Inactivated ; immunology

Background: Listeria monocytogenes is a food-borne intracellular bacterium which possesses many virulence factors that enable it to overcome the host immune system and of particular importance are surface proteins InlA and InlB which have a crucial role in initiating infection. The aim of this study is to detect the incidence of L. monocytogenes infection in placental tissue from women with spontaneous abortions by targeting InlB genes-based polymerase chain reaction. Methods: In one hundred and eleven pregnant women suffering from spontaneous abortions, about 25 grams of the placental tissue from each person was homogenized and centrifuged for about 15 min at 5000 rpm at 2-8°C. A specific set of primers was used for detection of L. monocytogenes InlB gene using conventional PCR technique. Results: Out of 111 placental tissue harvested from women with abortions, only 11 (9.9%) were proven to be positive for InlB gene. The highest rate of positivity (18.9%) was observed in the age group 20-29 years old. Of the 11 cases reported to be positive for listeriosis, 8 (72.7%) cases had their abortions in the first trimester. Conclusion Listeria monocytogenes may have a noteworthy role in pregnancy loss and should be considered when there are spontaneous abortions.
Listeriosis ; Listeria monocytogenes ; Abortion, Spontaneous

Listeria monocytogenes is an important zoonotic foodborne pathogen that can tolerate a number of environmental stresses. RsbR, an upstream regulator of the sigma B (SigB) factor, is thought to sense environmental challenges and trigger the SigB pathway. In Bacillus subtilis, two phosphorylation sites in RsbR are involved in activating the SigB pathway and a feedback mechanism, respectively. In this study, the role of RsbR in L. monocytogenes under mild and severe stresses was investigated. Strains with genetic deletion (ΔrsbR), complementation (C-ΔrsbR), and phosphorylation site mutations in the rsbR (RsbR-T175A, RsbR-T209A, and RsbR-T175A-T209A) were constructed to evaluate the roles of these RsbR sequences in listerial growth and survival. SigB was examined at the transcriptional and translational levels. Deletion of rsbR reduced listerial growxth and survival in response to acidic stress. Substitution of the phosphorylation residue RsbR-T175A disabled RsbR complementation, while RsbR-T209A significantly upregulated SigB expression and listerial survival. Our results provide clear evidence that two phosphorylation sites of RsbR are functional in L. monocytogenes under acidic conditions, similar to the situation in B. subtilis.
Alanine/genetics* ; Bacillus subtilis ; Bacterial Proteins/metabolism* ; Binding Sites ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Homeostasis ; Hydrogen-Ion Concentration ; Listeria monocytogenes/metabolism* ; Listeriosis/microbiology* ; Mutation ; Phenotype ; Phosphoproteins/metabolism* ; Phosphorylation ; Sigma Factor/metabolism* ; Stress, Physiological

BACKGROUND: Listeriosis caused by Listeria monocytogenes has a high case-fatality rate (CFR) of approximately 20% to 30%. An increasing incidence of listeriosis has been reported in many countries recently. We investigated the annual incidence, clinical characteristics, and outcomes of listeriosis at three different hospitals in Korea and evaluated the effects of appropriate empiric antimicrobial treatments on patient outcomes. METHODS: We retrospectively collected the data of all culture-positive cases of human listeriosis from three hospitals of different sizes in Korea during 2006–2016 and calculated the annual number of cases and incidence per 100,000 admissions. RESULTS: A total of 58 patients with L. monocytogenes were included in this study. The incidence of listeriosis was significantly higher in 2013–2016 than in 2006–2012 (RR 3.1; 95% CI 1.79–5.36; P < 0.001), mainly because of an increase in patients over 60 years of age (RR 3.69; 95% CI 1.70–8.02; P < 0.001). Multivariate analysis showed that healthcare-associated infection (adjusted OR, 12.15; 95% CI, 2.56–86.01; P=0.004) and empirical treatment with first-line antimicrobial agents (adjusted OR, 0.08; 95% CI, 0.00–0.63; P=0.044) were associated with CFR. CONCLUSIONS: Healthcare-associated infections caused by L. monocytogenes are associated with high CFR. Adequate initial empirical treatments could reduce CFR, suggesting that careful consideration of an empirical antimicrobial regimen is warranted for elderly or immunocompromised patients admitted to the hospital.
Aged ; Anti-Infective Agents ; Humans ; Immunocompromised Host ; Incidence* ; Korea ; Listeria monocytogenes ; Listeriosis* ; Multivariate Analysis ; Retrospective Studies

Listeriosis is a rare foodborne infection caused by Listeria monocytogenes. It is 12–20 times more prevalent in pregnant women compared to the general population, with a 20–40% mortality rate in neonates. Early treatment with appropriate antimicrobial agents is critical for pregnancy outcomes; however, the infection is difficult to control because the nonspecific clinical manifestations and rarity of the disease often preclude early diagnosis. We encountered 2 cases of pregnancy-associated listeriosis that occurred at 29 and 37 weeks of gestation. Both neonates were delivered by emergent cesarean section due to fetal condition, and one of the preterm infants died immediately after birth. Pregnancy-associated listeriosis should be considered in the management of unexplained fever or inflammatory conditions in pregnant women.
Anti-Infective Agents ; Cesarean Section ; Chorioamnionitis* ; Early Diagnosis ; Female ; Fever ; Humans ; Infant, Newborn ; Infant, Premature ; Listeria monocytogenes ; Listeriosis* ; Mortality ; Parturition ; Pregnancy ; Pregnancy Outcome ; Pregnant Women

This study aimed to investigate the prevalence and molecular characteristics of Listeria monocytogenes in cooked products in Zigong City, China. The overall occurrence of the L. monocytogenes in the ready-to-eat (RTE) shops and mutton restaurants surveyed was 16.2% (141/873). An occurrence of 13.5% was observed in RTE pork, 6.5% in RTE vegetables, and more than 24.0% in either cooked mutton or cooked haggis. Serotype 1/2b (45.4%), 1/2a (33.3%), and 1/2c (14.2%) were the predominant types. By comparing the clonal complexes (CCs) based on multilocus sequence typing (MLST) of the L. monocytogenes from cooked foods in Zigong City and 33 listeriosis cases from different districts of China, CC87, CC9, CC8, and CC3 were showed to be prevalent in cooked products and CC87 and CC3 were the first two frequent types in the 33 clinic-source strains. All CC87 stains harbored the newly reported Listeria pathogenicity island 4 (LIPI-4) gene fragment ptsA, and all CC3 strains possessed the Listeria pathogenicity island 3 (LIPI-3) gene fragment llsX. These may increase the occurrence of the strains belonging to CC87 and CC3 in listeriosis cases in China and also underline the risk of infection owing to the consumption of the cooked products from Zigong. ST619 (serotype 1/2b) harbored both llsX and ptsA, indicating a potential hypervirulent sequence type in Zigong.
China ; epidemiology ; Cooking ; Fast Foods ; microbiology ; Food Contamination ; Food Microbiology ; Humans ; Listeria monocytogenes ; genetics ; pathogenicity ; Listeriosis ; epidemiology ; microbiology ; Meat ; microbiology ; Multilocus Sequence Typing ; Prevalence ; Seasons

OBJECTIVETo test the effect of the c-Met inhibitor cabozantinib in inhibiting infections by Listeria monocytogenes (LM) in mice.

METHODSC57BL/6 mice at 6 weeks of age were subjected to intraperitoneal injection of LM and randomized into 4 groups for treatment with intraperitoneal injection of PBS, intragastric administration of cabozantinib (20 µg/g), intraperitoneal injection of ampicillin (Amp, 20 µg/g), or cabozantinib plus Amp. The survival curves were drawn for each group, and the number of bacteria in the blood and brain tissues was determined; serum IL-10 level and NF-κB p65 level in the cerebrospinal fluid (CSF) were assayed, and Evans Blue (EB) content and pathological changes in brain were examined.

RESULTSCompared with PBS-treated mice, the mice treated with cabozantinib showed a significantly higher survival rate, lower bacterial counts in the blood and brain (P<0.05 or 0.001), lower IL-10 (P<0.05) and NF-κB p65 levels (P<0.01), lower brain EB content (P<0.001), and milder pathological changes in the brain. The blood and brain bacterial counts (P<0.001), IL-10 (P<0.01) and NF-κB p65 levels (P<0.001), and brain EB content (P<0.001) were all significantly lower in mice treated with the combination of drugs than in mice treated with cabozantinib alone.

CONCLUSIONCabozantinib can inhibit LM infection in mice and has important values in developing new anti-intracellular infection drug.

Anilides ; pharmacology ; Animals ; Brain ; microbiology ; pathology ; Injections, Intraperitoneal ; Interleukin-10 ; blood ; Listeria monocytogenes ; drug effects ; Listeriosis ; drug therapy ; Mice ; Mice, Inbred C57BL ; Pyridines ; pharmacology ; Transcription Factor RelA ; cerebrospinal fluid

We aimed to investigate the potential pathogenic profile and antibiotic resistance of Listeria monocytogenes isolated from ready-to-eat food in China. Antimicrobial resistance was determined by broth microdilution following the Clinical and Laboratory Standards Institute protocol. Molecular serotyping, virulence, and resistance genes were identified using PCR. Multi-locus sequence typing was performed on resistant strains. A total of 11.53% (113/980) isolates were resistant, from which 82.3% (93/113) harbored all the virulence genes tested. The resistant strains were subtyped into 18 sequence types (STs), from which ST2, ST5, ST8, and ST9 were involved in listeriosis. This study indicated that several L. monocytogenes isolates from ready-to-eat foods in China have pathogenic potential and are resistant to antibiotics, including antibiotics used as medicines by humans for listeriosis treatment.
Anti-Bacterial Agents ; pharmacology ; China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; Fast Foods ; microbiology ; Food Microbiology ; Listeria monocytogenes ; genetics ; isolation & purification ; pathogenicity ; Listeriosis ; epidemiology ; microbiology ; Multilocus Sequence Typing ; Virulence