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1.
Mikrochim Acta ; 191(6): 361, 2024 06 01.
Article in English | MEDLINE | ID: mdl-38822891

ABSTRACT

A one-shot CO2 laser-based strategy to generate conductive reduced graphene oxide (rGO) decorated with nanoceria (nCe) is proposed. The 2D/0D rGO-nCe films, integrated as catalytic sensing layers in paper-based sensors, were employed for on-site monitoring of indoor fogging treatments against Listeria monocytogenes (Lm), a ubiquitous pathogenic bacterium. The rGO-nCe laser-assisted synthesis was optimized to preserve the rGO film morphological and electron-transfer features and simultaneously integrate catalytic nCe. The films were characterized by microscopical (SEM), spectroscopical (EDX, Raman, and FTIR), and electrochemical techniques. The most performing film was integrated into a nitrocellulose substrate, and the complete sensor was assembled via a combination of xurography and stencil printing. The rGO-nCe sensor's catalytic activity was proved toward the detection of H2O2, obtaining sensitive determination (LOD = 0.3 µM) and an extended linear range (0.5-1500 µM). Eventually, the rGO-nCe sensor was challenged for the real-time continuous monitoring of hydrogen peroxide aerosol during no-touch fogging treatment conducted following the EU's recommendation for biocidal product use. Treatment effectiveness was proved toward three Lm strains characterized by different origins, i.e., type strain ATCC 7644, clinical strain 338, and food strain 641/6II. The sensor allows for discrimination and quantification treatments at different environmental biocidal amounts and fogging times, and correlates with the microbiological inhibition, promoting the proposed sensor as a useful tool to modulate and monitor no-touch treatments.


Subject(s)
Disinfection , Graphite , Hydrogen Peroxide , Lasers , Listeria monocytogenes , Paper , Graphite/chemistry , Hydrogen Peroxide/chemistry , Listeria monocytogenes/drug effects , Listeria monocytogenes/isolation & purification , Disinfection/methods , Cerium/chemistry , Limit of Detection , Electrochemical Techniques/methods , Electrochemical Techniques/instrumentation , Catalysis
2.
Br J Hosp Med (Lond) ; 85(5): 1-4, 2024 May 30.
Article in English | MEDLINE | ID: mdl-38815971

ABSTRACT

We present an unusual case of Listeria monocytogenes rhomboencephalitis in a young, healthy patient. Although L. monocytogenes meningitis is usually associated with immunodeficiency, rhomboencephalitis is more commonly seen in immunocompetent patients. The wide differential for rhomboencephalitis can create a diagnostic challenge. Without prompt pathogen identification and appropriate antibiotic regimen, L. monocytogenes central nervous system infections can be fatal. Cerebro-Spinal Fluid (CSF) Polymerase Chain Reaction (PCR) aided a prompt diagnosis and adjustment of therapy to achieve a good patient outcome.


Subject(s)
Immunocompetence , Listeria monocytogenes , Listeriosis , Humans , Listeria monocytogenes/isolation & purification , Listeriosis/diagnosis , Listeriosis/drug therapy , Anti-Bacterial Agents/therapeutic use , Male , Rhombencephalon/microbiology , Magnetic Resonance Imaging , Meningitis, Listeria/diagnosis , Meningitis, Listeria/drug therapy , Adult , Encephalitis/microbiology , Encephalitis/diagnosis , Polymerase Chain Reaction
3.
BMC Infect Dis ; 24(1): 477, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38720244

ABSTRACT

We report a very rare case of Listeria multiple brain abscesses manifested as delirium, which represented diagnostic and therapeutic challenges overcome only by the close cooperation between Infectious Diseases and Neuroradiology, without which a satisfactory outcome would not be achieved.An elderly man presented with confusion and drowsiness with a background of type-II diabetes mellitus. Although computed tomography of the brain only showed frontal lobe oedema, contrast magnetic resonance (MR) imaging showed numerous irregular rim-enhancing lesions containing central diffusion restriction, suggesting multiple pyogenic cerebral abscesses of unclear aetiology. Thereafter, Listeria monocytogenes was isolated from blood cultures, suggesting this as the causative organism. Deemed unsuitable for neurosurgical drainage, the patient received medical management with a protracted course of antibiotics. This case was extremely challenging, due to 1) the impossibility of source control, 2) the small number of effective antibiotics available to treat this condition, and 3) the inevitable antibiotic side-effects, derived from long-term exposure. A successful outcome was only possible thanks to strict close multidisciplinary follow up, requiring frequent MR imaging and a judicious antibiotic choice, including monitoring of their side-effects. Due to the rarity of this condition, there is lack of guidance on its management, hence the importance of multidisciplinary involvement with very close imaging and antibiotic monitoring.


Subject(s)
Anti-Bacterial Agents , Brain Abscess , Listeria monocytogenes , Listeriosis , Humans , Male , Brain Abscess/microbiology , Brain Abscess/drug therapy , Brain Abscess/diagnostic imaging , Listeriosis/drug therapy , Listeriosis/microbiology , Listeriosis/diagnosis , Anti-Bacterial Agents/therapeutic use , Listeria monocytogenes/isolation & purification , Aged , Magnetic Resonance Imaging , Tomography, X-Ray Computed , Brain/diagnostic imaging , Brain/pathology , Brain/microbiology , Delirium/drug therapy
4.
Euro Surveill ; 29(19)2024 May.
Article in English | MEDLINE | ID: mdl-38726694

ABSTRACT

Listeria monocytogenes (Lm) is a bacterium widely distributed in the environment. Listeriosis is a severe disease associated with high hospitalisation and mortality rates. In April 2019, listeriosis was diagnosed in two hospital patients in Finland. We conducted a descriptive study to identify the source of the infection and defined a case as a person with a laboratory-confirmed Lm serogroup IIa sequence type (ST) 37. Six cases with Lm ST 37 were notified to the Finnish Infectious Diseases Registry between 2015 and 2019. Patient interviews and hospital menus were used to target traceback investigation of the implicated foods. In 2021 and 2022, similar Lm ST 37 was detected from samples of a ready-to-eat plant-based food product including fava beans. Inspections by the manufacturer and the local food control authority indicated that the food products were contaminated with Lm after pasteurisation. Our investigation highlights the importance that companies producing plant-based food are subject to similar controls as those producing food of animal origin. Hospital menus can be a useful source of information that is not dependent on patient recall.


Subject(s)
Disease Outbreaks , Food Microbiology , Listeria monocytogenes , Listeriosis , Humans , Listeria monocytogenes/isolation & purification , Listeria monocytogenes/genetics , Listeriosis/epidemiology , Listeriosis/microbiology , Finland/epidemiology , Female , Male , Foodborne Diseases/epidemiology , Foodborne Diseases/microbiology , Middle Aged , Aged , Food Contamination , Adult , Fabaceae/microbiology
5.
Anal Chem ; 96(21): 8543-8551, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38748432

ABSTRACT

In this study, the covalently fixed "end-on" orientation of a monoclonal Listeria monocytogenes antibody (mAb-Lis) to amino terminated oligo (ethylene glycol)-capped gold nanoparticles (NH2-TEG-AuNPs) was used to fabricate an in-house lateral flow strip (LFS), namely, the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS. The aim was to evaluate the performance of the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS in detecting L. monocytogenes. The proposed LFS enabled the sensitive detection of L. monocytogenes in 15 min with a visual limit of detection of 102 CFU/mL. Quantitative analysis indicated an LOD at 10 CFU/mL. The fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS showed no cross-reactivity with other pathogenic bacteria and practical performance across different food matrices, including human blood, milk, and mushroom samples. Furthermore, the clinical performance of the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS for detecting L. monocytogenes was evaluated by using 12 clinical samples validated by the hemoculture method. It demonstrated excellent concordance with the reference methods, with no false-positive or false-negative results observed. Therefore, the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS serves as a promising candidate for a point-of-care test (POCT), enabling the rapid, precise, and highly sensitive detection of L. monocytogenes in clinical samples and contaminated food.


Subject(s)
Antibodies, Monoclonal , Gold , Listeria monocytogenes , Metal Nanoparticles , Listeria monocytogenes/isolation & purification , Listeria monocytogenes/immunology , Gold/chemistry , Metal Nanoparticles/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/chemistry , Humans , Limit of Detection , Food Microbiology , Milk/microbiology , Milk/chemistry , Antibodies, Bacterial/chemistry , Antibodies, Bacterial/immunology , Antibodies, Immobilized/chemistry , Antibodies, Immobilized/immunology , Animals , Listeriosis/microbiology , Listeriosis/diagnosis
6.
Swiss Med Wkly ; 154: 3745, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38701492

ABSTRACT

AIMS OF THE STUDY: Listeriosis is a notifiable disease in Switzerland. In summer 2022, the Swiss Federal Office of Public Health noticed an increase in reports of listeriosis cases, indicating a possible ongoing outbreak. Here we present the approaches applied for rapidly confirming the outbreak, detecting the underlying source of infection and the measures put in place to eliminate it and contain the outbreak. METHODS: For close surveillance and early detection of outbreak situations with their possible sources, listeriosis patients in Switzerland are systematically interviewed about risk behaviours and foods consumed prior to the infection. Listeria monocytogenes isolates derived from patients in medical laboratories are sent to the National Reference Laboratory for Enteropathogenic Bacteria and Listeria, where they routinely undergo whole-genome sequencing. Interview and whole-genome sequencing data are continuously linked for comparison and analysis. RESULTS: In summer 2022, 20 patient-derived L. monocytogenes serotype 4b sequence type 388 strains were found to belong to an outbreak cluster (≤10 different alleles between neighbouring isolates) based on core genome multilocus sequence typing analysis. Geographically, 18 of 20 outbreak cases occurred in northeastern Switzerland. The median age of patients was 77.4 years (range: 58.1-89.7), with both sexes equally affected. Rolling analysis of the interview data revealed smoked trout from a local producer as a suspected infection source, triggering an on-site investigation of the production facility and sampling of the suspected products by the responsible cantonal food inspection team on 15 July 2022. Seven of ten samples tested positive for L. monocytogenes and the respective cantonal authority ordered a ban on production and distribution as well as a product recall. The Federal Food Safety and Veterinary Office released a nationwide public alert covering the smoked fish products concerned. Whole-genome sequencing analysis confirmed the interrelatedness of the L. monocytogenes smoked trout product isolates and the patient-derived isolates. Following the ban on production and distribution and the product recall, reporting of new outbreak-related cases rapidly dropped to zero. CONCLUSIONS: This listeriosis outbreak could be contained within a relatively short time thanks to identification of the source of contamination through the established combined approach of timely interviewing of every listeriosis patient or a representative and continuous molecular analysis of the patient- and food-derived L. monocytogenes isolates. These findings highlight the effectiveness of this well-established, joint approach involving the federal and cantonal authorities and the research institutions mandated to contain listeriosis outbreaks in Switzerland.


Subject(s)
Disease Outbreaks , Listeria monocytogenes , Listeriosis , Whole Genome Sequencing , Humans , Switzerland/epidemiology , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Listeriosis/epidemiology , Listeriosis/diagnosis , Whole Genome Sequencing/methods , Male , Aged , Female , Aged, 80 and over , Multilocus Sequence Typing , Middle Aged , Food Microbiology , Foodborne Diseases/epidemiology , Foodborne Diseases/microbiology , Interviews as Topic
7.
Sensors (Basel) ; 24(8)2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38676242

ABSTRACT

Foodborne pathogens are microbes present in food that cause serious illness when the contaminated food is consumed. Among these pathogens, Listeria monocytogenes is one of the most serious bacterial pathogens, and causes severe illness. The techniques currently used for L. monocytogenes detection are based on common molecular biology tools that are not easy to implement for field use in food production and distribution facilities. This work focuses on the efficacy of an electrochemical biosensor in detecting L. monocytogenes in chicken broth. The sensor is based on a nanostructured electrode modified with a bacteriophage as a bioreceptor which selectively detects L. monocytogenes using electrochemical impedance spectroscopy. The biosensing platform was able to reach a limit of detection of 55 CFU/mL in 1× PBS buffer and 10 CFU/mL in 1% diluted chicken broth. The biosensor demonstrated 83-98% recovery rates in buffer and 87-96% in chicken broth.


Subject(s)
Biosensing Techniques , Chickens , Dielectric Spectroscopy , Food Microbiology , Listeria monocytogenes , Listeria monocytogenes/isolation & purification , Biosensing Techniques/methods , Animals , Food Microbiology/methods , Electrodes
8.
Vet Microbiol ; 293: 110086, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38615477

ABSTRACT

Listeriosis is a zoonotic disease caused by Listeria monocytogenes and Listeria ivanovii. The genus Listeria currently includes 27 recognized species and is found throughout the environment. The number of systematic studies on antimicrobial resistance in L. monocytogenes isolates from domestic farms using antimicrobial substances is limited. Importantly, dairy ruminant farms are reservoir of hypervirulent lineage I L. monocytogenes isolates, previously associated with human clinical cases. Considering that the classes of antibiotics used in food-producing domestic animals are frequently the same or closely related to those used in human medicine, studies about the impact of antibiotic use on the acquisition of antibiotic resistance in Listeria spp. in domestic animal farms are, therefore, of high importance. Here, susceptibility to 25 antibiotics was determined. Eighty-one animal-related, 35 food and 21 human pathogenic Listeria spp. isolates and 114 animal-related non-pathogenic Listeria spp. isolates were tested. Whole genome sequencing data was used for molecular characterization. Regarding L. monocytogenes, 2 strains from the clinical-associated linage I showed resistance to erythromycin, both related to dairy ruminants. Acquired resistance to one antibiotic was exhibited in 1.5% of L. monocytogenes isolates compared with 14% of non-pathogenic Listeria spp. isolates. Resistance to tetracycline (7.9%), doxycycline (7.9%), penicillin (4.4%), and ampicillin (4.4%) were the most frequently observed in non-pathogenic Listeria spp. While resistance to two or more antibiotics (5.6%) was most common in Listeria spp., isolates, resistance to one antibiotic was also observed (1.6%). The present results show that non-pathogenic Listeria spp. harbour antimicrobial resistance genes.


Subject(s)
Anti-Bacterial Agents , Listeria , Listeriosis , Microbial Sensitivity Tests , Animals , Listeria/drug effects , Listeria/genetics , Listeria/classification , Listeria/isolation & purification , Anti-Bacterial Agents/pharmacology , Spain/epidemiology , Listeriosis/microbiology , Listeriosis/veterinary , Listeriosis/epidemiology , Genotype , Drug Resistance, Bacterial/genetics , Whole Genome Sequencing , Listeria monocytogenes/drug effects , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Humans , Phenotype
9.
Braz J Microbiol ; 55(2): 1759-1772, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38622468

ABSTRACT

Due to specific bacterial microbiota, raw milk cheeses have appreciated sensory properties. However, they may pose a threat to consumer safety due to potential pathogens presence. This study evaluated the microbiological contamination of 98 raw milk cheeses from Beira Baixa, Portugal. Presence and enumeration of Coagulase Positive Staphylococci (CPS), Listeria monocytogenes, Salmonella spp., pathogenic Escherichia coli, and indicator microorganisms (non-pathogenic E. coli and Listeria spp.) was attained. E. coli antimicrobial resistance (AMR) was also evaluated. PCR and/or Whole genome sequencing (WGS) was used to characterize E. coli, Salmonella spp. and L. monocytogenes isolates. Sixteen cheeses (16.3%) were classified as Satisfactory, 59 (60.2%) as Borderline and 23 (23.5%) as Unsatisfactory/Potential Injurious to Health. L. monocytogenes, CPS > 104 cfu g-1, Extraintestinal pathogenic E. coli (ExPEC) and Salmonella spp. were detected in 4.1%, 6.1%, 3.1% and 1.0% of the samples, respectively. Listeria innocua (4.1%) and E. coli > 104 cfu g-1 (16.3%) were also detected. AMR E. coli was detected in 23/98 (23.5%) of the cheese samples, of which two were multidrug resistant. WGS identified genotypes already associated to human disease and Listeria spp. cluster analysis indicated that cheese contamination might be related with noncompliance with Good Hygiene Practices during cheese production.


Subject(s)
Cheese , Food Microbiology , Milk , Cheese/microbiology , Portugal , Animals , Milk/microbiology , Food Safety , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Listeria monocytogenes/classification , Bacteria/isolation & purification , Bacteria/classification , Bacteria/genetics , Hygiene , Escherichia coli/genetics , Escherichia coli/isolation & purification , Food Contamination/analysis , Drug Resistance, Bacterial , Humans
10.
Anal Chem ; 96(17): 6588-6598, 2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38619494

ABSTRACT

How timely identification and determination of pathogen species in pathogen-contaminated foods are responsible for rapid and accurate treatments for food safety accidents. Herein, we synthesize four aggregation-induced emissive nanosilicons with different surface potentials and hydrophobicities by encapsulating four tetraphenylethylene derivatives differing in functional groups. The prepared nanosilicons are utilized as receptors to develop a nanosensor array according to their distinctive interactions with pathogens for the rapid and simultaneous discrimination of pathogens. By coupling with machine-learning algorithms, the proposed nanosensor array achieves high performance in identifying eight pathogens within 1 h with high overall accuracy (93.75-100%). Meanwhile, Cronobacter sakazakii and Listeria monocytogenes are taken as model bacteria for the quantitative evaluation of the developed nanosensor array, which can successfully distinguish the concentration of C. sakazakii and L. monocytogenes at more than 103 and 102 CFU mL-1, respectively, and their mixed samples at 105 CFU mL-1 through the artificial neural network. Moreover, eight pathogens at 1 × 104 CFU mL-1 in milk can be successfully identified by the developed nanosensor array, indicating its feasibility in monitoring food hazards.


Subject(s)
Food Microbiology , Listeria monocytogenes , Machine Learning , Listeria monocytogenes/isolation & purification , Cronobacter sakazakii/isolation & purification , Silicon Dioxide/chemistry , Point-of-Care Systems , Animals , Milk/microbiology , Milk/chemistry , Biosensing Techniques , Neural Networks, Computer
11.
Braz J Microbiol ; 55(2): 1783-1791, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38687417

ABSTRACT

The aim of the present study was to compare the performance of a nested polymerase chain reaction (nPCR) and a real-time PCR based on the amplification of the HlyA gene from Listeria monocytogenes using a plasmid DNA standard. Nested PCR was developed with an internal amplification control (IAC). Both techniques were validated in soft cheese samples by comparing their results with the results of the microbiological reference method ISO 11290-1:2017. Cheese samples artificially contaminated with 3.5 to 3,500 UFC/25 g were processed by ISO 11290-1:2017 and, at several times of culture, DNA samples were extracted. All cheeses contaminated with L. monocytogenes were positive for the microbiological method 96 h post contamination and for nPCR and real-time PCR 48 h post contamination. At this time, the HlyA gene was amplified in all contaminated samples. Both molecular techniques showed the same sensitivity, 30 copies/reaction or 3.5 UFC/25 g, when plasmid DNA standard or artificially contaminated cheese samples were used. Finally, eighty soft cheese samples obtained from local retail stores and tested by three methods were negative, indicating a 100% concordance in results. The development of an nPCR with IAC reinforces the reliability of the negative results without increasing the costs of the reaction. Besides, nPCR showed less sensitivity to the presence of inhibitory substances in the reaction. The use of one of these molecular techniques could be easily coupled to the microbiological method, serving as a screening method in the food industry for hygiene monitoring and early identification of contaminated foods.


Subject(s)
Cheese , Food Microbiology , Listeria monocytogenes , Polymerase Chain Reaction , Real-Time Polymerase Chain Reaction , Cheese/microbiology , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Real-Time Polymerase Chain Reaction/methods , Polymerase Chain Reaction/methods , Food Microbiology/methods , Hemolysin Proteins/genetics , Bacterial Toxins/genetics , DNA, Bacterial/genetics , Heat-Shock Proteins
12.
J Clin Microbiol ; 62(5): e0157623, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38441926

ABSTRACT

Whole-genome sequencing has become the method of choice for bacterial outbreak investigation, with most clinical and public health laboratories currently routinely using short-read Illumina sequencing. Recently, long-read Oxford Nanopore Technologies (ONT) sequencing has gained prominence and may offer advantages over short-read sequencing, particularly with the recent introduction of the R10 chemistry, which promises much lower error rates than the R9 chemistry. However, limited information is available on its performance for bacterial single-nucleotide polymorphism (SNP)-based outbreak investigation. We present an open-source workflow, Prokaryotic Awesome variant Calling Utility (PACU) (https://github.com/BioinformaticsPlatformWIV-ISP/PACU), for constructing SNP phylogenies using Illumina and/or ONT R9/R10 sequencing data. The workflow was evaluated using outbreak data sets of Shiga toxin-producing Escherichia coli and Listeria monocytogenes by comparing ONT R9 and R10 with Illumina data. The performance of each sequencing technology was evaluated not only separately but also by integrating samples sequenced by different technologies/chemistries into the same phylogenomic analysis. Additionally, the minimum sequencing time required to obtain accurate phylogenetic results using nanopore sequencing was evaluated. PACU allowed accurate identification of outbreak clusters for both species using all technologies/chemistries, but ONT R9 results deviated slightly more from the Illumina results. ONT R10 results showed trends very similar to Illumina, and we found that integrating data sets sequenced by either Illumina or ONT R10 for different isolates into the same analysis produced stable and highly accurate phylogenomic results. The resulting phylogenies for these two outbreaks stabilized after ~20 hours of sequencing for ONT R9 and ~8 hours for ONT R10. This study provides a proof of concept for using ONT R10, either in isolation or in combination with Illumina, for rapid and accurate bacterial SNP-based outbreak investigation.


Subject(s)
Disease Outbreaks , Polymorphism, Single Nucleotide , Humans , Nanopore Sequencing/methods , High-Throughput Nucleotide Sequencing/methods , Phylogeny , Listeria monocytogenes/genetics , Listeria monocytogenes/classification , Listeria monocytogenes/isolation & purification , Whole Genome Sequencing/methods , Genome, Bacterial/genetics , Listeriosis/epidemiology , Listeriosis/microbiology , Sequence Analysis, DNA/methods , Nanopores , Bacteria/genetics , Bacteria/classification , Bacteria/isolation & purification
13.
Rev Neurol ; 76(12): 385-390, 2023 06 16.
Article in English, Spanish | MEDLINE | ID: mdl-37303100

ABSTRACT

INTRODUCTION: To date, few studies have explored the specific risk factors of patients with listeriosis who develop rhombencephalitis, and there is insufficient information regarding imaging findings and clinical symptoms in patients with this disease. This work aimed to analyze the imaging findings associated with L. monocytogenes rhombencephalitis in a cohort of patients with listeriosis. MATERIALS AND METHODS: We conducted a retrospective observational study of all declared cases of listeriosis in a tertiary hospital from Granada, Spain, from 2008 to 2021. Risk factors, comorbidities, and clinical outcomes were collected for all patients. In addition, clinical symptoms and magnetic resonance imaging (MRI) findings were included for those patients who developed rhombencephalitis. Descriptive and bivariate analyses were performed using SPSS statistical software (IBM SPSS, version 21). RESULTS: Our cohort comprised 120 patients with listeriosis (41.7% women, mean age: 58.6 ± 23.8 years), of which 10 (8.3%) had rhombencephalitis. The most frequent MRI findings in patients with confirmed rhombencephalitis were T2-FLAIR hyperintensity (100%), T1 hypointensity (80%), scattered parenchymal enhancement (80%), and cranial nerve enhancement (70%), while the most frequent anatomical involvement were pons, medulla oblongata, and cerebellum. Complications occurred in 6 patients (abscess in 4, hemorrhage in 2, hydrocephalus in 1). CONCLUSIONS: Rhombencephalitis is associated with an increased in-hospital mortality in patients with listeriosis. The anatomical distribution and imaging characteristics of neurolisteriosis could be useful to suggest the diagnosis. Future studies with greater sample size should explore the association between anatomical location, imaging patterns, and associated complications (e.g., hydrocephalus, hemorrhage), and clinical outcomes.


TITLE: Epidemiología, clínica y resultados de imagen de rombencefalitis causada por L. monocytogenes. Un estudio observacional.Introducción. Hasta la fecha, pocos estudios han explorado los factores de riesgo específicos de los pacientes con listeriosis que desarrollan rombencefalitis, y no hay suficiente información sobre los hallazgos de imagen y los síntomas clínicos en pacientes con esta enfermedad. El objetivo de este trabajo fue analizar los hallazgos de imagen asociados a la rombencefalitis por L. monocytogenes en una cohorte de pacientes con listeriosis. Materiales y métodos. Se realizó un estudio observacional retrospectivo de todos los casos declarados de listeriosis en un hospital terciario de Granada, España, desde 2008 hasta 2021. Se recogieron los factores de riesgo, las comorbilidades y los resultados clínicos de todos los pacientes. Además, se incluyeron los síntomas clínicos y los hallazgos de resonancia magnética (RM) de los pacientes que desarrollaron rombencefalitis. Se realizaron análisis descriptivos y bivariados utilizando el software estadístico SPSS (IBM SPSS, versión 21). Resultados. Nuestra cohorte incluyó a 120 pacientes con listeriosis (41,7%, mujeres; edad media: 58,6 ± 23,8 años), de los cuales 10 (8,3%) tenían rombencefalitis. Los hallazgos más frecuentes en la RM de los pacientes con rombencefalitis confirmada fueron hiperintensidad en T2-FLAIR (100%), hipointensidad en T1 (80%), realce parenquimatoso disperso (80%) y realce de los nervios craneales (70%), mientras que la afectación anatómica más frecuente fue en la protuberancia, la médula oblongada y el cerebelo. Se produjeron complicaciones en seis pacientes (absceso en cuatro, hemorragia en dos e hidrocefalia en uno). Conclusiones. La rombencefalitis se asocia a un aumento de la mortalidad intrahospitalaria en pacientes con listeriosis. La distribución anatómica y las características de imagen de la neurolisteriosis podrían ser útiles para sugerir el diagnóstico. Futuros estudios con mayor tamaño muestral deberían explorar la asociación entre la localización anatómica, los patrones de imagen y las complicaciones asociadas (por ejemplo, hidrocefalia y hemorragia), y los resultados clínicos.


Subject(s)
Infectious Encephalitis , Listeria monocytogenes , Listeriosis , Rhombencephalon , Infectious Encephalitis/diagnostic imaging , Infectious Encephalitis/epidemiology , Infectious Encephalitis/microbiology , Rhombencephalon/diagnostic imaging , Rhombencephalon/microbiology , Listeria monocytogenes/isolation & purification , Listeriosis/complications , Humans , Male , Female , Adult , Middle Aged , Aged , Spain/epidemiology , Longitudinal Studies
14.
Anal Chim Acta ; 1281: 341905, 2023 Nov 15.
Article in English | MEDLINE | ID: mdl-38783743

ABSTRACT

BACKGROUND: Listeria monocytogenes is a pathogenic bacterium that can lead to severe illnesses, especially among vulnerable populations. Therefore, the development of rapid and sensitive detection methods is vital to prevent and manage foodborne diseases. In this study, we used tetraethylenepentamine (TEPA)-functionalized magnetic nanoparticles (MNPs) and a loop-mediated isothermal amplification (LAMP)-based CRISPR/Cas12a-based biosensor to concentrate and detect, respectively, L. monocytogenes. LAMP enables DNA amplification at a constant temperature, providing a highly suitable approach for point-of-care testing (POCT). The ability of CRISPR/Cas12a to cleave ssDNA reporter, coupled with TEPA-functionalized MNPs effective attachment to negatively charged bacteria, forms a promising biosensor. RESULTS: The LAMP assay was meticulously developed by selecting specific primers and designing crRNA sequences targeting a specific region within the hly gene of L. monocytogenes. We selected primer and refined the amplification conditions by systematically exploring a temperature range from 59 °C to 69 °C, ensuring the attainment of optimal performance. This process was complemented by systematic optimization of LAMP-CRISPR/Cas12a system parameters. In particular, we successfully established the optimal ssDNA reporter concentrations (0-1.2 µM) and Cas12a-mediated trans-cleavage times (0-20 min), crucial components that underpin the effectiveness of the LAMP-CRISPR/Cas12a-based biosensor. For optimizing parameters in capturing L. monocytogenes using TEPA-functionalized MNPs, capture efficiency was significantly enhanced through adjustments in TEPA-functionalized MNPs concentration, incubation times, and magnetic separation duration. Large-volume (20 mL) magnetic separation exhibited a 10-fold sensitivity improvement over conventional methods. Utilizing TEPA-functionalized MNPs, the LAMP-CRISPR/Cas12a-based biosensor achieved detection limits of 100 CFU mL-1 in pure cultures and 100 CFU g-1 in enoki mushrooms. SIGNIFICANCE: The integration of this novel technique with the LAMP-CRISPR/Cas12a-based biosensor enhances the accuracy and sensitivity of L. monocytogenes detection in foods, and it can be a promising biosensor for POCT. The 10-fold increase in sensitivity compared to conventional methods makes this approach a groundbreaking advancement in pathogenic bacteria detection for food safety and public health.


Subject(s)
Biosensing Techniques , CRISPR-Cas Systems , Listeria monocytogenes , Magnetite Nanoparticles , Nucleic Acid Amplification Techniques , Listeria monocytogenes/isolation & purification , Listeria monocytogenes/genetics , Biosensing Techniques/methods , CRISPR-Cas Systems/genetics , Magnetite Nanoparticles/chemistry , Limit of Detection , Food Microbiology/methods , Bacterial Proteins , Endodeoxyribonucleases , Molecular Diagnostic Techniques , CRISPR-Associated Proteins
15.
J Dairy Sci ; 105(12): 9450-9462, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36207178

ABSTRACT

Foodborne pathogens detection is important to ensure food safety and human health. In this study, we designed a comet structure to rapidly and sensitively detect foodborne Listeria monocytogenes. This method combined isothermal sequence exchange amplification (SEA) and surface-enhanced Raman spectroscopy. Listeria monocytogenes DNA could be rapidly amplified at a constant temperature via SEA with a pair of modified primers, which rendered the precise thermal control instrumentation unnecessary. Efficient SEA amplification generated a large number of DNA duplexes that could be easily captured by streptavidin-modified magnetic bead and AuMB@Ag-isothiocyanate fluorescein antibody (anti-FITC). AuMB@Ag-anti-FITC was used as a signal probe, which generated a significant excitation signal at 1,616 cm-1 for quantitative detection and analysis. The results displayed sensitive detection of L. monocytogenes in cheese from 2.0 × 101 cfu/mL to 2.0 × 106 cfu/mL within 1.0 h with a detection limit of 7.8 cfu/mL. Furthermore, this comet structure displayed the desirable specificity as its specific primers and amplified DNA ends were attached to streptavidin-modified magnetic beads and AuMB@Ag-anti-FITC, respectively. We expected that the method devised would provide a promising new approach to screening for L. monocytogenes and guarantee the microbiological safety of dairy products.


Subject(s)
Cheese , Food Contamination , Listeria monocytogenes , Cheese/microbiology , DNA Primers/genetics , Food Microbiology , Listeria monocytogenes/isolation & purification , Spectrum Analysis, Raman , Streptavidin
16.
Front Public Health ; 10: 712657, 2022.
Article in English | MEDLINE | ID: mdl-35372200

ABSTRACT

Listeria monocytogenes is the causative agent of listeriosis, a highly lethal disease initiated after the ingestion of Listeria-contaminated food. This species comprises different serovars, from which 4b, 1/2a, and 1/2b cause most of the infections. Among the different proteins involved in pathogenesis, the internalins A (InlA) and B (InlB) are the best characterized, since they play a major role in the enterocyte entry of Listeria cells during early infection. Due to their covalent attachment to the cell wall and location on the bacterial surface, along with their exclusive presence in the pathogenic L. monocytogenes, these proteins are also used as detection targets for this species. Even though huge advancements were achieved in the enrichment steps for subsequent Listeria detection, few studies have focused on the improvement of the antibodies for immunodetection. In the present study, recombinant InlA and InlB produced in Escherichia coli were used as targets to generate antibodies via phage display using the human naïve antibody libraries HAL9 and HAL10. A set of five recombinant antibodies (four against InlA, and one against InlB) were produced in scFv-Fc format and tested in indirect ELISA against a panel of 19 Listeria strains (17 species; including the three main serovars of L. monocytogenes) and 16 non-Listeria species. All five antibodies were able to recognize L. monocytogenes with 100% sensitivity (CI 29.24-100.0) and specificity (CI 88.78-100.0) in all three analyzed antibody concentrations. These findings show that phage display-derived antibodies can improve the biological tools to develop better immunodiagnostics for L. monocytogenes.


Subject(s)
Antibodies, Monoclonal , Bacterial Proteins , Listeria monocytogenes , Antibodies, Monoclonal/metabolism , Bacterial Proteins/immunology , Bacteriophages , Cell Surface Display Techniques , Humans , Listeria monocytogenes/isolation & purification
17.
Mikrochim Acta ; 189(3): 94, 2022 02 08.
Article in English | MEDLINE | ID: mdl-35132460

ABSTRACT

Recent research in the field of electrochemical biosensors equipped with peptides and nanomaterials have been categorized, reviewed, and critically analyzed. Indeed, using these innovative biosensors can revolutionize biomedical diagnostics in the future. Saving lives, time, and money in this field will be considered as some main benefits of this type of diagnosis. Here, these biosensors have been categorized and evaluated in four main sections. In the first section, the focus is on investigating the types of electrochemical peptide-based nanobiosensors applied to detect pathogenic microorganisms, microbial toxins, and viruses. In the second section, due to the importance of rapid diagnosis and prognosis of various cancers, the electrochemical peptide-based nanobiosensors designed to detect cancer biomarkers have been reviewed and analyzed. In the third section, the electrochemical peptide-based nanobiosensors, which were applied to detect the essential and effective biomolecules in the various diseases, and health control, including enzymes, hormones, biomarkers, and other biomolecules, have been considered. Finally, using a comprehensive analysis, all the used elements in these biosensors have been presented as conceptual diagrams that can effectively guide researchers in future developments. The essential factors in evaluating and analyzing these electrochemical peptide-based nanobiosensors such as analyte, peptide sequence, functional groups interacted between the peptide sequences and other biosensing components, the applied nanomaterials, diagnostic techniques, detection range, and limit of detection have also been included. Other analyzable items such as the type of used redox marker and the location of the peptide sequence against the signal transducer were also considered.


Subject(s)
Biosensing Techniques , Electrochemical Techniques , Neoplasms/diagnosis , Peptides/chemistry , Humans , Listeria monocytogenes/isolation & purification , Nanostructures/chemistry , Proteins/analysis , Staphylococcus aureus/isolation & purification
18.
J Microbiol Methods ; 192: 106378, 2022 01.
Article in English | MEDLINE | ID: mdl-34818574

ABSTRACT

Listeria monocytogenes belongs to the category of facultative anaerobic bacteria, and is the pathogen of listeriosis, potentially lethal disease for humans. There are many similarities between L. monocytogenes and other non-pathogenic Listeria species, which causes great difficulties for their correct identification. The level of L. monocytogenes contamination in food remains high according to statistics from the Food and Drug Administration. This situation leads to food recall and destruction, which has caused huge economic losses to the food industry. Therefore, the identification of Listeria species is very important for clinical treatment and food safety. This work aims to explore an efficient classification algorithm which could easily and reliably distinguish Listeria species. We attempted to classify Listeria species by incorporating denoising autoencoder (DAE) and machine learning algorithms in matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). In addition, convolutional neural networks were used to map the high dimensional original mass spectrometry data to low dimensional core features. By analyzing MALDI-TOF MS data via incorporating DAE and support vector machine (SVM), the identification accuracy of Listeria species was 100%. The proposed classification algorithm is fast (range of seconds), easy to handle, and, more importantly, this method also allows for extending the identification scope of bacteria. The DAE model used in our research is an effective tool for the extraction of MALDI-TOF mass spectrometry features. Despite the fact that the MALDI-TOF MS dataset examined in our research had high dimensionality, the DAE + SVM algorithm was still able to exploit the hidden information embedded in the original MALDI-TOF mass spectra. The experimental results in our work demonstrated that MALDI-TOF mass spectrum combined with DAE + SVM could easily and reliably distinguish Listeria species.


Subject(s)
Food Microbiology/methods , Listeria monocytogenes/classification , Machine Learning , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Algorithms , Food Safety , Humans , Listeria monocytogenes/isolation & purification , Listeriosis/diagnosis , Listeriosis/prevention & control
19.
Microbiol Spectr ; 9(3): e0137721, 2021 12 22.
Article in English | MEDLINE | ID: mdl-34908469

ABSTRACT

The dormancy continuum hypothesis states that in response to stress, cells enter different stages of dormancy ranging from unstressed living cells to cell death, in order to ensure their long-term survival under adverse conditions. Exposure of Listeria monocytogenes cells to sublethal stressors related to food processing may induce sublethal injury and the viable-but-nonculturable (VBNC) state. In this study, exposure to acetic acid (AA), hydrochloric acid (HCl), and two disinfectants, peracetic acid (PAA) and sodium hypochlorite (SH), at 20°C and 4°C was used to evaluate the potential induction of L. monocytogenes strain Scott A into different stages of dormancy. To differentiate the noninjured subpopulation from the total population, tryptic soy agar with 0.6% yeast extract (TSAYE), supplemented or not with 5% NaCl, was used. Sublethally injured and VBNC cells were detected by comparing plate counts obtained with fluorescence microscopy and by using combinations of carboxyfluorescein and propidium iodide (viable/dead cells). Induction of sublethal injury was more intense after PAA treatment. Two subpopulations were detected, with phenotypes of untreated cells and small colony variants (SCVs). SCVs appeared as smaller colonies of various sizes and were first observed after 5 min of exposure to 5 ppm PAA at 20°C. Increasing the stress intensity from 5 to 40 ppm PAA led to earlier detection of SCVs. L. monocytogenes remained culturable after exposure to 20 and 30 ppm PAA for 3 h. At 40 ppm, after 3 h of exposure, the whole population was considered nonculturable, while cells remained metabolically active. These results corroborate the induction of the VBNC state. IMPORTANCE Sublethally injured and VBNC cells may evade detection, resulting in underestimation of a food product's microbial load. Under favorable conditions, cells may regain their growth capacity and acquire new resistant characteristics, posing a major threat for public health. Induction of the VBNC state is crucial for foodborne pathogens, such as L. monocytogenes, the detection of which relies almost exclusively on the use of culture recovery techniques. In the present study, we confirmed that sublethal injury is an initial stage of dormancy in L. monocytogenes that is followed by the VBNC state. Our results showed that PAA induced SCVs (a phenomenon potentially triggered by external factors) and the VBNC state in L. monocytogenes, indicating that tests of lethality based only on culturability may provide false-positive results regarding the effectiveness of an inactivation treatment.


Subject(s)
Acetic Acid/pharmacology , Disinfectants/pharmacology , Hydrochloric Acid/pharmacology , Listeria monocytogenes/growth & development , Peracetic Acid/pharmacology , Sodium Hypochlorite/pharmacology , Food Contamination/analysis , Food Handling , Food Microbiology , Foodborne Diseases/microbiology , Foodborne Diseases/prevention & control , Humans , Listeria monocytogenes/drug effects , Listeria monocytogenes/isolation & purification , Listeriosis/prevention & control
20.
Microbiologyopen ; 10(6): e1246, 2021 11.
Article in English | MEDLINE | ID: mdl-34964295

ABSTRACT

Identification, source tracking, and surveillance of food pathogens are crucial factors for the food-producing industry. Over the last decade, the techniques used for this have moved from conventional enrichment methods, through species-specific detection by PCR to sequencing-based methods, whole-genome sequencing (WGS) being the ultimate method. However, using WGS requires the right infrastructure, high computational power, and bioinformatics expertise. Therefore, there is a need for faster, more cost-effective, and more user-friendly methods. A newly developed method, ON-rep-seq, combines the classical rep-PCR method with nanopore sequencing, resulting in a highly discriminating set of sequences that can be used for species identification and also strain discrimination. This study is essentially a real industry case from a salmon processing plant. Twenty Listeria monocytogenes isolates were analyzed both by ON-rep-seq and WGS to identify and differentiate putative L. monocytogenes from a routine sampling of processing equipment and products, and finally, compare the strain-level discriminatory power of ON-rep-seq to different analyzing levels delivered from the WGS data. The analyses revealed that among the isolates tested there were three different strains. The isolates of the most frequently detected strain (n = 15) were all detected in the problematic area in the processing plant. The strain level discrimination done by ON-rep-seq was in full accordance with the interpretation of WGS data. Our findings also demonstrate that ON-rep-seq may serve as a primary screening method alternative to WGS for identification and strain-level differentiation for surveillance of potential pathogens in a food-producing environment.


Subject(s)
Food Microbiology , Food-Processing Industry , Listeria monocytogenes/classification , Nanopore Sequencing , Polymerase Chain Reaction , Salmon/microbiology , Animals , Cost-Benefit Analysis , Genome, Bacterial , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Phylogeny , Sequence Analysis, DNA , Whole Genome Sequencing
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