Meningoencephalitis due to Listeria monocytogenes in a Young Immunocompetent Patient: Case Report with Literature Review

Meningoencephalitis secondary to Listeria monocytogenes (L. monocytogenes) mainly affects newborns, the elderly and immunocompromised people;there are extremely rare cases in which said infection occurs in immunocompetent individuals. We present the case of a young adult patient without immunocompromise, who developed meningoencephalitis due to L. monocytogenes;This case is exceptional, since it occurred in an individual outside the classic age group, in addition to not having risk factors, which is why it should be considered an atypical causal agent.

Infection with Listeria monocytogenes meningoencephalitis:A case report

BACKGROUND Listeria meningitis is an infectious disease of the central nervous system caused by Listeria monocytogenes.This bacterium is widely present in the natural environment and can be transmitted through channels such as food and water.Patients usually show symptoms such as fever,headache,and neck stiffness.In severe cases,coma,convulsions,or even death may occur.Traditional diagnostic methods,such as cerebrospinal fluid(CSF)culture and serological tests,have certain limitations.Although CSF culture is the“gold standard”for diagnosis,it is time-consuming and has a relatively low positivity rate.Serological detection may also result in false positive or false negative results.The emergence of metagenomic sequencing(mNGS)technology has led to a significant break-through in diagnosing Listeria meningitis,allowing quick and accurate detection of various pathogens in samples.CASE SUMMARY Here,we present the case of a previously healthy 64-year-old woman diagnosed with Listeria meningitis using mNGS.She was successfully treated with intravenous ampicillin and meropenem,without any complications.CONCLUSION Listeria meningitis must be considered,especially in patients who fail to show improvement with first-line antibiotic treatments.mNGS significantly reduces the diagnosis time,supporting timely treatment of patients.

Identification of Salmonella and Listeria monocytogenes by Near-infrared Spectroscopy and PCA

Near-infrared spectra of pathogenic bacteria (salmonella and Listeria monocytogenes ) were determined, and the spectral data were analyzed by the projection discriminant analysis based on principal component analysis (PCA). The expected results were obtained. The results showed that salmonella and L. monocytogenes could be distinguished from each other by the near-infrared spectroscopy of the whole cells, cell walls or cytoplasm.

Effects of Sodium Lactate on the Survival of <i>Listeria Monocytogenes</i>, <i>Escherichia coli</i>O157:H7, and <i>Salmonella</i>spp. in Cooked Ham at Refrigerated and Abuse Temperatures

The objective of this study was to determine the effect of sodium lactate on the survival of Listeria monocytogenes, Escherichia coli O157: H7, and Salmonella spp. in cooked ham during storage at refrigerated and abuse temperatures. Cooked ham was added with 0% - 3% lactate, inoculated with a multiple-strain mixture of L. monocytogenes, E. coli O157: H7, or Salmonella spp. and stored at 4oC - 15oC for up to 35 day. The growth of the three pathogens was inhibited in ham containing 3% lactate, and no growth of E. coli O157: H7 and Salmonella spp. occurred at the lowest storage tem- peratures of 6 and 8oC, respectively. In ham containing no lactate, the average growth rates were 0.256 - 0.380 log CFU/day for L. monocytogenes at 4oC - 8oC, 0.242 - 0.315 log CFU/day for E. coli O157: H7 at 8oC - 15oC, and 0.249 - 0.328 log CFU/day for Salmonella spp. at 10oC - 15oC. The addition of 1% or 2% lactate significantly (P < 0.05) reduced the growth rates of the three pathogens, and the effect was more profound at lower temperatures. Salmonella spp. were more sensitive to the effect of lactate than L. monocytogenes and E. coli O157: H7. Polynomial models were developed to describe the growth rates of the three pathogens as affected by the lactate concentration and storage tem- perature. Results from this study demonstrate the effect of lactate on the growth of L. monocytogenes, E. coli O157: H7, and Salmonella spp. in cooked ham and indicate the effective lactate concentrations and storage temperatures that can be used to enhance the microbiological safety of ready-to-eat ham products.

Biofilm Determination of Listeria monocytogenes That Isolated from Different Sources

The study was conducted for the detection of Listeria monocytogenes bacteria from different sources （CSF and blood） obtained from patients in Pediatric hospital and from food sources like （yogurt, raw vegetables and raw milk, sausage）. Ten isolates were isolated from 150 specimens one of them from CSF and one isolate isolated from blood samples the others isolated from food specimens 6 isolates isolated from sausage and 2 from raw vegetables. Isolates were identified traditionally involved culture methods based on selective enrichment and plating followed by the characterization of Listeria spp. based on colony morphology, sugar fermentation and haemolytic properties, identification by Api listeria was done. Determine the isolates that produce biofilm by tissue culture plate method. The highest biofilm forming strains ofListeria monocytogenes isolates appear in No. （D10, El, E5 and E7） OD reading each of them is （0.13, 0.09, 0.11 and 0.19） respectively, the lowest or poor biofilm forming strains appear in No. （D11, D12, E2, E3, E4 and E6） that optical density （OD） reading are （0.04, 0.03, 0.05, 0.04, 0.05 and 0.03） respectively by comparing with control prepared in well （A12） that stained by crystal violate without putting any isolates and the OD reading is （0.003）. Confirmation by PCR was done only for four isolates that produce biofilm （D10 and El） that obtained from CSF and blood sample and for （E5 and E7） that obtained from food samples.

实验动物中单核细胞增生性李氏菌(Listeria monocytogenes)分离方法的研究

以一种新的培养基用于斜光照射法快速鉴别李氏菌,它优于加入抑制剂的分离培养基,具有快速、准确的特点。通过对几种选择性增菌液的比较,发现CRT的增菌效果最好.它与新的分离平板结合使用,分离灵敏度比原方法提高5～10倍。同时简化了内脏匀浆分离李氏菌的方法。并用此法和改进后的CRT方法对人工感染的动物进行了分离,结果证实这两种方法切实可行.对北京地区几个单位的动物也进行了分离,结果为阴性。

Rhombencephalitis caused by Listeria monocytogenes with hydrocephalus and intracranial hemorrhage:A case report and review of the literature

BACKGROUND Listeria monocytogenes(L. monocytogenes), a Gram-positive facultatively intracellular bacterium, is the causative agent of human listeriosis. Listeria infection is usually found in immunocompromised patients, including elderly people, pregnant women, and newborns, whereas it is rare in healthy people. L.monocytogenes may cause meningitis, meningoencephalitis, and some very rare and severe complications, such as hydrocephalus and intracranial hemorrhage,which cause high mortality and morbidity worldwide. Up to now, reports on hydrocephalus and intracranial hemorrhage due to L. monocytogenes are few.CASE SUMMARY We herein report a case of rhombencephalitis caused by L. monocytogenes in a 29-year-old man. He was admitted to the hospital with a 2-d history of headache and fever. He consumed unpasteurized cooked beef two days before appearance.His medical history included type 2 diabetes mellitus, and contaminated beef intake 2 d before onset. Cerebrospinal fluid analysis revealed Gram-positive rod infection, and blood culture was positive for L. monocytogenes. Magnetic resonance imaging findings suggested rhombencephalitis and hydrocephalus.Treatment was started empirically and then modified according to the blood culture results. Repeated CT images were suggestive of intracranial hemorrhage.Although the patient underwent aggressive external ventricular drainage, he died of a continuing deterioration of intracranial conditions.CONCLUSION Hydrocephalus, intracranial hemorrhage, and inappropriate antimicrobial treatment are the determinations of unfavorable outcomes.

PCR-based methodologies for detection and characterization of Listeria monocytogenes and Listeria ivanovii in foods and environmental sources

Listeria monocytogenes is an important foodborne pathogen responsible for listeriosis,a fatal disease.It is widely distributed in various foods and environmental sources.In this review,we focused on addressing PCR-based technologies,including conventional PCR,qPCR and droplet digital PCR(ddPCR).Specifically,we described(a)conventional PCR and mono-,duplex-and multiplex-qPCR methodologies;(b)development and applications of gene HlyA-,Iap-,PrfA–and SsrA-based conventional and qPCR assays as well as PCR assays targeting newly identified gene targets for specific detection of L.monocytogenes;differentiation of viable from dead L.monocytogenes by qPCR in conjugation with propidium monoazide pretreatment;PCR-based serotype identification of L.monocytogenes isolates;PCR-based detection of L.ivanovii,infecting ruminants,differentiation of L.monocytogenes from other Listeria species;and sigB-gene based PCR identification of Listeria spp;(c)applications of ddPCR in detection of L.monocytogenes;and(d)application of qPCR assays in detection and subtyping of L.monocytogenes in milk and dairy products;meats,meat products and meat-processing environment;and seafood,seafood products and processing environment.Our goal was to provide a relatively comprehensive overview of PCR-based methodologies available in detection,characterization and subtyping of various strains of L.monocytogenes in foods and environmental sources.

In vitro Selection of DNA Aptamers and Fluorescence-Based Recognition for Rapid Detection Listeria monocytogenes

Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.

Prevalence and methodologies for detection,characterization and subtyping of Listeria monocytogenes and L.ivanovii in foods and environmental sources

Listeria monocytogenes,one of the most important foodborne pathogens,can cause listeriosis,a lethal disease for humans.L.ivanovii,which is closely related to L.monocytogenes,is also widely distributed in nature and infects mainly warm-blooded ruminants,causing economic loss.Thus,there are high priority needs for methodologies for rapid,specific,cost-effective and accurate detection,characterization and subtyping of L.monocytogenes and L.ivanovii in foods and environmental sources.In this review,we(A)described L.monocytogenes and L.ivanovii,world-wide incidence of listeriosis,and prevalence of various L.monocytogenes strains in food and environmental sources;(B)comprehensively reviewed different types of traditional and newly developed methodologies,including culture-based,antigen/antibody-based,LOOP-mediated isothermal amplification,matrix-assisted laser desorption ionization-time of flight-mass spectrometry,DNA microarray,and genomic sequencing for detection and characterization of L.monocytogenes in foods and environmental sources;(C)comprehensively summarized different subtyping methodologies,including pulsed-field gel electrophoresis,multi-locus sequence typing,ribotyping,and phage-typing,and whole genomic sequencing etc.for subtyping of L.monocytogenes strains from food and environmental sources;and(D)described the applications of these methodologies in detection and subtyping of L.monocytogenes in foods and food processing facilities.

Survival of <i>Listeria monocytogenes</i>during Frying of Chicken Burger Patties

This study was aimed to determine sufficient frying time to reduce the number of Listeria monocytogenes present in chicken burger patties to non-detectable level which is fit for human consumption. Commercially available chicken burger patties were artificially contaminated with L. monocytogenes at level of approximately 9 log CFU/ml. The contaminated chicken burger patties were cooked for 0, 2, 4, 5, 8, and 10 minutes to determine survival of L. monocyto-genes. Results demonstrated a linear correlation between mean log reduction of L. monocytogenes and frying time. L. monocytogenes was not detected in chicken burger patties that were cooked for 6 minutes and above. As a result from this study, it is suggested that a minimum frying time for burger patties is 6 minutes. This can be treated as a safety measure to avoid consequences of consumption of undercooked burger patties.

Listeria monocytogenes following orthotopic liver transplantation:Central nervous system involvement and review of the literature

Listeria monocytogene is a well-recognized cause of bacteremia in immunocompromised individuals, including solid organ transplant recipients, but has been rarely reported following orthotopic liver transplantation. We describe a case of listeria meningitis that occurred within a week after liver transplantation. The patient developed a severe headache that mimicked tacrolimus encephalopathy, and was subsequently diagnosed with listeria meningitis by cerebrospinal fluid culture. The infection was successfully treated with three-week course of intravenous arnpicillin. Recurrent hepatitis C followed and was successfully treated with interferon alfa and ribavirin. Fourteen cases of listeriosis after orthotopic liver transplantation have been reported in the English literature. Most reported cases were successfully treated with intravenous ampicillin. There were four cases of listeria meningitis, and the mortality of them was 50%. Early detection and treatment of listeria meningitis are the key to obtaining a better prognosis.

Inhibitory Effect of Live-Attenuated Listeria Monocytogenes-based Vaccines Expressing MIA Gene on Malignant Melanoma

Listeria monocytogenes(LM),a Gram-positive facultative intracellular bacterium,can be used as an effective exogenous antigen expression vector in tumor-target therapy.But for successful clinical application,it is necessary to construct attenuated LM stain that is safe yet retains the potency of LM based on the full virulent pathogen.In this study,attenuated LM and recombinants of LM expressing melanoma inhibitory activity(MIA) were constructed successfully.The median lethal dose(LD 50) and invasion efficiency of attenuated LM strains were detected.The recombinants were utilized for immunotherapy of animal model of B16F10 melanoma.The level of MIA mRNA expression in tumor tissue was detected by using real-time polymerase chain reaction(PCR) with specific sequence,meanwhile the anti-tumor immune response was assayed by flow cytometric analysis and enzyme-linked immunosorbent spot(ELISPOT) assay.The results showed the toxicity and invasiveness of attenuated LM were decreased as compared with LM,and attenuated LM expressing MIA,especially the double-genes attenuated LM recombinant,could significantly induce anti-tumor immune response and inhibit tumor growth.This study implicates attenuated LM may be a safer and more effective vector for immunotherapy of melanoma.

Application Progress of Recombinant Attenuated Listeria monocytogenes in Tumor Immunotherapy

Much progress of application of bacterial vaccine in treatment and prevention of tumor was acquired,which showed broad prospect in clinical study of animals and humans. Listeria monocytogenes( L. monocytogenes) was considered much important by virtue of its special characteristic of biology and immunology.L. monocytogenes was ingested by professional or part-time phagocytes,survived and proliferated in the phagocytes under synergism of toxic factor secreted by itself,meanwhile,the cellular and humoral immune response was induced. Antigenic gene of specific tumor was loaded in the attenuated L. monocytogenes,which can enhance immune response of host cells. Effective cell targeted to enter tumor tissue and acted on tumor cells to induce apoptosis of tumor cells. Tumor degenerated not easy to reappear. Therefore,recombinant attenuated L. monocytogenes was a safe and effective anti-cancer vaccine vector. Now the work of researchers mainly focuses on solving practical problem in clinical application. Biological characteristics of L. monocytogenes,feasibility and superiority of L. monocytogenes as targeted vaccine vector,problem and prospect of L. monocytogenes in clinical application of anti-tumor were reviewed in this paper.

Use of Bacteriocin Producing <i>Lactococcus lactis</i>subsp. <i>lactis</i>LABW4 to Prevent <i>Listeria monocytogenes</i>Induced Spoilage of Meat

A bacteriocin producing strain of Lactococcus lactis subsp. lactis LABW4 was isolated from naturally fermented milk product which exhibited strong antibacterial activity against Listeria monocytogenes MTCC657, a food spoilage psychrophilic organism. Both cell free and heat killed supernatants of LABW4 were effective to produce zones of inhibition against L. monocytogenes in vitro. The antibacterial metabolite(s) of LABW4 showed strong cidal effect on the growth of L. monocytogenes. Meat samples, mixed with heat killed supernatant of LABW4 when inoculated with Listeria, remain fresh up to 25 days in refrigerated condition whereas spoilage started immediately after 24 hours of inoculation for control sets. Enhancement of Lactate dehydrogenase of L. monocytogenes upon treatment with LABW4 cell free supernatant suggested its lytic mode of action. Cell lysis or degradations were also supported by scanning electron micrograph of treated cells.

Detection of Listeria monocytogenes in Dairy Food by Loop-mediated Isothermal Amplification(LAMP)

[Objective] This study aimed to detect the reliability of LAMP method for detecting Listeria monocytogenes in dairy food. [Method] Based on the sequence of hlyA gene encoding listeriolysin O in Listeria monocytogenes, the LAMP method was established for detecting Listeria monocytogenes in dairy food. [Result] The es- tablished LAMP rapid detection method has .high specificity and sensitivity, which are equivalent to those of real-time fluorescent quantitative PCR. The detection re- sults of Listeria monocytogenes in dairy food by established LAMP method were completely consistent with those by bacterial isolation method. [Conclusion] The de- tection results of Listeria monocytogenes by LAMP method can be directly identified by naked eye, so the established LAMP method was suitable for the detection of Listeria monocytogenes in dairy food in emergency situations.

Antimicrobial Resistance,Virulence Profile,and Molecular Characterization of Listeria monocytogenes Isolated from Ready-to-eat Food in China,2013-2014

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

Loop-Mediated Isothermal Amplification (LAMP) for the Detection of <i>Listeria monocytogenes</i>and Major Pathogenic Serotypes

Rapid identification and characterization of Listeria monocytogenes are required for the food industry, epidemiological studies, and disease prevention and control. However, typing procedures are labor-intensive and time-consuming, and they require technical expertise, a panel of sera and reference culture strains or sophisticated and expensive equipment. To improve upon traditional diagnostic methods for L. monocytogenes we developed and evaluated an efficient procedure for the specific identification of L. monocytogenes and the major pathogenic serotypes of the species based on loop-mediated isothermal amplification (LAMP). Four individual reactions were designed using primers targeting any L. monocytogenes serotypes (LAMP-AS) and the 1/2a (LAMP-1/2a), 1/2b (LAMP-1/2b), and 4b (LAMP-4b) serotypes. The procedure distinguished L. monocytogenes from closely genetically related species and the targeted serotypes. Cross-reactivity with a few rare serotypes isolated from food or clinical samples did not impair the usefulness of the procedure. Thus, our approach constitutes a fast, easy and low-cost alternative for L. monocytogenes diagnosis and serotyping and may be useful for surveillance and epidemiological investigation programs.

Combination Use of PFGE and Drug-resistant Analysis in the Epidemiological Investigation of Listeria Monocytogenes

Listeria monocytogenes is the pathogen of listeriosis and it causes severe infections like septicemia, encephalitis, and meningitis, especially in immunocompromised individuals, newborns, and pregnant women. Its wide distribution in the environment and ability to survive or even grow under adverse conditions has made L. monocytogenes an important public health concern and in food industry.

Brainstem abscesses caused by Listeria monocytogenes:A case report

BACKGROUNDIntracranial Listeria infections are common in newborns and immunocompromisedindividuals, but brainstem abscesses are rare.CASE SUMMARYWe report a rare case of brainstem abscesses caused by Listeria monocytogenes in apreviously healthy adult patient. The patient’s magnetic resonance imagingexamination showed multiple brain abscesses, and his second cerebrospinal fluidculture test indicated the presence of Listeria monocytogenes. Despite earlyempirical therapy, the patient’s condition progressively deteriorated. Because thepatient's abscesses were located in the brainstem and multiple lobes, surgery wasnot possible. The patient died 40 d after admission.CONCLUSIONThis case highlights the importance of rational clinical use of drugs to avoidpotentially serious infectious complications.