INTRODUCTION

Neurolisteriosis is caused by Listeria monocytogenes, a gram-positive microorganism. It usually affects vulnerable population including pregnant women, neonates, immunocompromised individuals, and elderly persons. This report describes a case of neurolisteriosis in a 31-year-old immunocompetent man.

This case involves a 31-year-old Filipino male who presented with decrease sensorium. A lumbar puncture was performed, and polymerase chain reaction (PCR) testing of the cerebrospinal fluid confirmed the presence of Listeria monocytogenes. On the fifth day of hospitalization, the patient developed unilateral sixth cranial nerve palsy and facial nerve palsy. He was treated with intravenous ampicillin for 21 days, resulting in significant improvement in the cranial nerve deficits.

It is the first neurolisteriosis case in this institution. There is only one published neurolisteriosis case in the Philippines which presented with brain abscess. Neurolisteriosis, although uncommon, is one of the differential diagnoses in patients presenting with fever, headache, and nuchal rigidity. Isolation of Listeria monocytogenes in the cerebrospinal fluid and blood culture is diagnostic. Neurolisteriosis is an invasive disease which can result in neurologic sequalae such as cranial nerve palsies. Targeted treatment aids in good clinical outcomes.

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

Objective To investigate the effect of long intergenic non-coding RNA COX2 (lincRNA-COX2) on apoptosis and polarization of Listeria monocytogenes (Lm)-infected RAW264.7 cells. Methods RAW264.7 cells were cultured and divided into control group (uninfected cells), Lm infection group, negative control of small interfering RNA (si-NC) group, si-NC and Lm infection group, small interfering RNA of lincRNA-COX2 (si-lincRNA-COX2) group, si-lincRNA-COX2 and Lm infection group. RAW264.7 cells were infected with MOI=10 Lm for 6 hours, and then the inhibition efficiency of siRNA transfection was detected by fluorescence microscope and quantitative real-time PCR (qRT-PCR). The expression levels of cleaved-caspase-3(c-caspase-3), caspase-3, B-cell lymphoma-2 (Bcl2), Bcl2 associated X protein (BAX), arginase 1 (Arg1), inducible nitric oxide synthase (iNOS) were detected by Western blot analysis. Results c-caspase-3/caspase-3, BAX/Bcl2 and iNOS were significantly up-regulated, while the level of Arg1 was down-regulated in Lm-infected RAW264.7 cells compared with control group. LincRNA-COX2 knockdown inhibited the increase of protein levels for BAX/Bcl2, c-caspase-3/caspase-3 and iNOS in Lm-infected RAW264.7 cells, while the level of Arg1 in Lm-infected RAW264.7 cells was up-regulated. Conclusion Knockdown of lincRNA-COX2 can inhibit cell apoptosis and suppress the macrophage polarization into M1 type in Lm-infected RAW264.7 cells.
Apoptosis/genetics* ; bcl-2-Associated X Protein/metabolism* ; Caspase 3/metabolism* ; Cyclooxygenase 2/metabolism* ; Listeria monocytogenes/pathogenicity* ; Macrophages/microbiology* ; RNA, Long Noncoding/metabolism* ; RNA, Small Interfering/genetics* ; Animals ; Mice

Aims: This study was designed to evaluate the effectiveness of the synthesised carvacrol loaded chitosan nanoparticles (CLCNPs) on the growing and pre-formed biofilms of Listeria monocytogenes isolated from slaughterhouses. Methodology and results: The swab samples were collected from knives, hocks and cutting tables representing slaughterhouses meat contact surfaces (MCS), while those samples from walls and floors represent slaughterhouses meat non-contact surfaces (MNCS). The bacteriological analysis revealed the existence of L. monocytogenes with a prevalence rate of 3.3, 10 and 6.7% for knives, hocks and cutting tables, respectively and 2.2 and 6.6% for walls and floors, respectively. The isolates L. monocytogenes were assayed for biofilm production by the crystal violet binding assay method. Among the 10 L. monocytogenes isolates, 10%, 50% and 30% of the isolates were found to be strong, moderate and weak biofilm producers, respectively. The activities of carvacrol, chitosan nanoparticles (NPs) and CLCNPs against the only strong biofilm producer strain of L. monocytogenes were tested by microtiter plate assay. The minimum inhibitory concentrations (MIC) values were 3.75 mg/mL for CAR, 5 mg/mL for chitosan NPs and 0.62 mg/mL for CLCNPs. CLCNPs inhibit the produced biofilm by 35.79, 73.37 and 77.76%, when 0.5 MIC, 1 MIC and 2 MIC were used, respectively. Furthermore, the pre-formed L. monocytogenes biofilms were significantly reduced from 1.01 (control) OD570 to 0.40 and 0.29 OD570 by applying 2 MIC and 4 MIC doses, respectively. Conclusion, significance and impact of study The data generated is promising to develop bio-green disinfectants to inhibit biofilm formation by L. monocytogenes in the food processing environment and control its adverse effects for consumers.
Chitosan--chemistry ; Listeria monocytogenes ; Nanoparticles

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

The ban on addition of antibiotics in animal feed in China has made the search for new antibiotics substitutes, e.g. bacteriocin, a hot topic in research. The present study successfully isolated an antibacterial substance producing strain of Bacillus sp. from alpaca feces by agar diffusion method, using Escherichia coli, Salmonella enterica, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus and Listeria monocytogenes as indicator bacteria. The isolated strain was named as B. licheniformis SXAU06 based on colony morphology, Gram staining and 16S rRNA gene sequence. The antibacterial substance was isolated and purified through a series of procedures including (NH4)2SO4 precipitation, chloroform extraction, molecular interception and SDS-PAGE analysis. Bioinformatics analysis of the LC-MS/MS data indicated that the antibacterial substance was a bacteriocin-like substance (BLIS) with an approximate molecular weight of 14 kDa, and it was designated as BLIS_SXAU06. BLIS_SXAU06 exhibited high resistance to treatment of proteinase K, high temperature, high acidity and alkalinity. BLIS_SXAU06 was heterologously expressed in E. coli and the recombinant BLIS_SXAU06 exhibited effective antibacterial activity against S. aureus, S. epidermidis, M. luteus, and L. monocytogenes, showing potential to be investigated further.
Animals ; Anti-Bacterial Agents/pharmacology* ; Bacillus licheniformis ; Bacteriocins/pharmacology* ; China ; Chromatography, Liquid ; Escherichia coli/genetics* ; Listeria monocytogenes ; RNA, Ribosomal, 16S ; Staphylococcus aureus ; Tandem Mass Spectrometry

Listeria monocytogenes is an important food-borne pathogen. The distribution and survival of L. monocytogenes are related to its ability to form biofilms. Biofilms are resistant to adverse environments, and bacteria separated from the biofilms may lead to persistent food contaminations. The formation, maturation and structure of biofilms depend on a variety of external and internal factors, among which a variety of regulatory mechanisms play important roles. This review summarizes the regulatory mechanisms (including intracellular, intercellular and interspecific interactions) involved in the biofilm formation of L. monocytogenes in order to control the biofilm formation in food processing environments, thus providing new intervention strategy for food safety.
Biofilms ; Food Contamination ; Food Safety ; Listeria monocytogenes

Aims: This study aims to isolate lactic acid bacteria (LAB) from various food sources to obtain a potent strain against Listeria monocytogenes. Methodology and results: A total of 68 LAB isolates were selected to evaluate their antimicrobial activity against L. monocytogenes, a foodborne pathogen and a causative agent of listeriosis. The selected isolate was identified and characterized. The isolate C23 from cabbage showed the highest antimicrobial activity against L. monocytogenes ATCC 7644 with inhibition ability of 73.94%. The isolate was closely related to Lactobacillus brevis by 16S rRNA sequencing and subsequently deposited in GenBank with an accession number of MN880215, named as L. brevis C23. The cell free supernatant (CFS) of L. brevis C23 had high tolerance in low pH and was able to withstand up to 60 °C. The proteinaceous nature of the antimicrobial agent was also confirmed through the enzymatic test. The CFS was stable on different detergents as well as bile salts. Under transmission electron microscopy (TEM), the inhibitory effect of CFS against L. monocytogenes was proven by causing cell lysis. Conclusion, significance and impact of study Bacteriocin-like inhibitory substances (BLIS) of L. brevis C23 showed very promising potential in food industrial application.
Lactobacillales ; Listeria monocytogenes ; Foodborne Diseases ; Sprains and Strains

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

Strain variability is one of the most important factors to influence the accuracy of foodborne pathogens risk assessment, such as Listeria monocytogenes, Salmonella spp. Strain-to-strain variation is defined as the inherent differences among identically treated strains of the same microbial species. The differences cannot be eliminated by changing test methods or improving test protocols. This review addresses presently related studies of strain variability. Based on the effect of strain variability on the outcome of risk assessment, we summarize sources of variabilities in food chain, strain phenotypic variabilities and the methods to integrate strain variability in growth and inactivation into predictive modelling, and indicate the inadequacies in the study of strain variability. We suggest further study the mechanism of strain variability, expand the comparison of variability among different sources, and integrate the variability of gene expression, protein and cell metabolism into the predictive modelling.
Food Microbiology ; Listeria monocytogenes/genetics* ; Risk Assessment ; Salmonella/genetics*