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Listeria screening

Siyue Gao, Brooke Pearson, Lili He
The existence of pathogenic bacteria in drinking water has been a threat to the safety of human well-being. Traditional methods to detect bacteria are standard plate counts or rapid methods such as ELISA and PCR. However, those methods can be time-consuming or require pre-enrichment when detecting low concentrations of bacteria. Filter membrane has been used for bacteria collection and culturing when monitoring environmental water samples. In this study, we applied surface enhanced Raman spectroscopy (SERS) to rapidly screen bacteria cells on a filter membrane based on the unique signal from an indicator molecule, 4-mercaptophenylboronic acid (4-mpba), that can specifically bind to the surface of bacteria through diol group in its structure and give off consistent SERS signal...
March 15, 2018: Journal of Microbiological Methods
Fulai Li, Fan Li, Dan Luo, Weihua Lai, Yonghua Xiong, Hengyi Xu
Infectious diseases caused by Listeria monocytogenes pose a great threat to public health worldwide. Therefore, a rapid and efficient method for L. monocytogenes detection is needed. In this study, a biotin-exposure-based immunomagnetic separation (IMS) method was developed. That is, biotinylated antibody was first targeted to L. monocytogenes. Then, streptavidin-functionalized magnetic nanoparticles were added and anchored onto L. monocytogenes cells indirectly through the strong noncovalent interaction between streptavidin and biotin...
August 9, 2018: Analytica Chimica Acta
Alejandro Garrido-Maestu, Sarah Azinheiro, Joana Carvalho, Marta Prado
Listeria monocytogenes continues to be one of the most important foodborne pathogens worldwide, either due to its incidence and/or to its high mortality rate. In the present study, a filtration-based protocol was applied for the screening of viable bacteria. Additionally, a complete method (enrichment, filtration, DNA extraction and real-time PCR detection) was evaluated in order to determine the capacity of this protocol to detect viable L. monocytogenes in food samples. A new multiplex qPCR detection system was designed, including an internal amplification control, both targets were detected with hydrolysis probes...
August 2018: Food Microbiology
Melaine A Kuenemann, Patricia A Spears, Paul E Orndorff, Denis Fourches
Peptidoglycan walls of gram positive bacteria are functionalized by glycopolymers called wall teichoic acid (WTA). In Listeria monocytogenes, multiple enzymes including the glucose-1-phosphate uridylyltransferase (GalU) were identified as mandatory for WTA galactosylation, so that the inhibition of GalU is associated with a significant attenuation of Listeria virulence. Herein, we report on a series of in silico predicted GalU inhibitors identified using structure-based virtual screening and experimentally validated to be effective in blocking the WTA galactosylation pathway in vitro...
March 8, 2018: Molecular Informatics
Marilize Le Roes-Hill, Kim Durrell, Alaric Prins, Paul R Meyers
The actinobacterium, strain M26T , was isolated from garden soil that was pre-treated with microwave radiation. The soil sample was collected in Roodepoort, Gauteng Province, South Africa as part of an antibiotic-screening programme. The isolate produced branched vegetative mycelium with sporangiophores bearing small sporangia ranging from 3 to 6 μm in diameter. Rapid genus identification revealed that the isolate belongs to the genus Streptosporangium. To confirm this result, the strain was subjected to polyphasic taxonomic characterisation...
March 7, 2018: Journal of Antibiotics
P Carvajal-Rondanelli, M Aróstica, C A Álvarez, C Ojeda, F Albericio, L F Aguilar, S H Marshall, F Guzmán
Previous work demonstrated that lysine homopeptides adopt a polyproline II (PPII) structure. Lysine homopeptides with odd number of residues, especially with 11 residues (K11), were capable of inhibiting the growth of a broader spectrum of bacteria than those with an even number. Confocal studies also determined that K11 was able to localize exclusively in the bacterial membrane, leading to cell death. In this work, the mechanism of action of this peptide was further analyzed focused on examining the structural changes in bacterial membrane induced by K11, and in K11 itself when interacting with bacterial membrane lipids...
February 21, 2018: Amino Acids
Quach Ngoc Tung, Nico Linzner, Vu Van Loi, Haike Antelmann
Gram-negative bacteria utilize glutathione (GSH) as their major LMW thiol. However, most Gram-positive bacteria do not encode enzymes for GSH biosynthesis and produce instead alternative LMW thiols, such as bacillithiol (BSH) and mycothiol (MSH). BSH is utilized by Firmicutes and MSH is the major LMW thiol of Actinomycetes. LMW thiols are required to maintain the reduced state of the cytoplasm, but are also involved in virulence mechanisms in human pathogens, such as Staphylococcus aureus, Mycobacterium tuberculosis, Streptococcus pneumoniae, Salmonella enterica subsp...
February 15, 2018: Free Radical Biology & Medicine
Fateme Akrami-Mohajeri, Zahra Derakhshan, Margherita Ferrantee, Negar Hamidiyan, Meysam Soleymani, Gea Oliveri Conti
Listeria monocytogenes is an important foodborne pathogen which its data in Iranian dairy products is limited. A total of 545 samples of traditional dairy products (raw milk, traditional cheese, traditional butter, traditional curd, and traditional ice cream) were collected from traditional dairy shops located in Yazd, Iran. L. monocytogenes was isolated, and positive samples were confirmed by polymerase chain reaction. Antibiotic sensitivity test was conducted to determine the antibiotic resistance. Listeria species were isolated from 11...
February 12, 2018: Food and Chemical Toxicology
Ileana Cocan, Ersilia Alexa, Corina Danciu, Isidora Radulov, Atena Galuscan, Diana Obistioiu, Attila Alexandru Morvay, Renata Maria Sumalan, Mariana-Atena Poiana, Georgeta Pop, Cristina Adriana Dehelean
The current study aimed to investigate ethanolic extracts from the following medicinal plant species cultivated in western Romania: Melissa officinalis L., Rosmarinus officinalis L. (RO) and Salvia officinalis L. (SO). Antioxidant activity, total phenolics content and a profile of the main hydroxycinnamic acids (HCAs), including caffeic, ferulic, coumaric and rosmarinic acids, was determined for each plant extract. The in vitro antimicrobial activity against four bacterial strains ( Escherichia coli , Listeria -, Pseudomonas aeruginosa and Staphylococcus aureus ), and the effect on cell viability in two melanoma cell lines (B164A5 murine melanoma and A375 human melanoma) was also assessed...
February 2018: Experimental and Therapeutic Medicine
Michelle M Gerst, Ahmed E Yousef
AIMS: To develop a microassay method to detect antimicrobials produced by spore-forming bacteria, thus speeding up the discovery of new antimicrobials. METHODS AND RESULTS: Environmental isolates were grown in 96-well plates, to allow production of antimicrobials agents, then treated with lysozyme and heat sequentially. Lysozyme-heat treatment inhibited or prevented spore-to-cell transformation, thus eliminating interference from spore outgrowth while detecting antimicrobials by indicator bacteria...
February 10, 2018: Journal of Applied Microbiology
Nurul Islam, Jaehyuk Choi, Kwang-Hyun Baek
Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T...
January 29, 2018: Foodborne Pathogens and Disease
Cristina Nastasă, Dan C Vodnar, Ioana Ionuţ, Anca Stana, Daniela Benedec, Radu Tamaian, Ovidiu Oniga, Brînduşa Tiperciuc
The global spread of bacterial resistance to drugs used in therapy requires new potent and safe antimicrobial agents. DNA gyrases represent important targets in drug discovery. Schiff bases, thiazole, and triazole derivatives are considered key scaffolds in medicinal chemistry. Fifteen thiazolyl-triazole Schiff bases were evaluated for their antibacterial activity, measuring the growth inhibition zone diameter, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC), against Gram-positive (Staphylococcus aureus, Listeria monocytogenes) and Gram-negative (Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa) bacteria...
January 11, 2018: International Journal of Molecular Sciences
Xiaofan Yu, Fang Chen, Ronghui Wang, Yanbin Li
The rapid detection of foodborne pathogens is critical to ensure food safety. The objective of this study is to select aptamers specifically bound to Escherichia coli O157:H7 using the whole-bacterium SELEX (Systematic Evolution of Ligands by Exponential Enrichment) and apply the selected aptamer to a QCM (quartz crystal microbalance) sensor for rapid and sensitive detection of target bacteria. A total of 19 rounds of selection against live E. coli O157:H7 and 6 rounds of counter selection against a mixture of Staphylococcus aureus, Listeria monocytogenes, and Salmonella Typhimurium, were performed...
January 20, 2018: Journal of Biotechnology
Jinjin Pei, Hai Jiang, Xinsheng Li, Wengang Jin, Yanduo Tao
Yak butter is one of the most important foods for the Tibetan people. Of note, its production yields waste yak milk as a by-product. In this work, waste yak milk protein hydrolysates made via Pepsin hydrolysis were shown to have antimicrobial activity. Furthermore, an innovative method of magnetic liposome adsorption combined with reversed-phase high performance liquid chromatography (RP-HPLC) was developed to screen for and purify the antimicrobial peptides. Two antimicrobial peptides were obtained and their amino acid sequences were determined by N-sequencing, namely Arg-Val-Met-Phe-Lys-Trp-Ala and Lys-Val-Ile-Ser-Met-Ile...
December 6, 2017: AMB Express
Kankanit Pisamayarom, Annop Suriyasomboon, Piyasak Chaumpluk
Monitoring food safety is essential for protecting the health and safety of consumers. Conventional methods used are time consuming and laborious, requiring anywhere from three to seven days to obtain results. Thus, better monitoring methods are required. In this study, a laminated lab-on-paper chip was developed, and its use for the screening of ready-to-eat seafood was demonstrated. The assay on a chip was based on loop-mediated isothermal DNA amplification (LAMP) of the hly gene of Listeria monocytogenes and fluorescence signal detection via SYBR GoldTM ...
November 28, 2017: Biosensors
Franck Cerutti, Ludovic Mallet, Anaïs Painset, Claire Hoede, Annick Moisan, Christophe Bécavin, Mélodie Duval, Olivier Dussurget, Pascale Cossart, Christine Gaspin, Hélène Chiapello
BACKGROUND: Small regulatory RNAs (sRNAs) are widely found in bacteria and play key roles in many important physiological and adaptation processes. Studying their evolution and screening for events of coevolution with other genomic features is a powerful way to better understand their origin and assess a common functional or adaptive relationship between them. However, evolution and coevolution of sRNAs with coding genes have been sparsely investigated in bacterial pathogens. RESULTS: We designed a robust and generic phylogenomics approach that detects correlated evolution between sRNAs and protein-coding genes using their observed and inferred patterns of presence-absence in a set of annotated genomes...
November 16, 2017: BMC Genomics
Bulent Ergun
Ganoderma lucidum (GL) is a mushroom used as a traditional remedy for the treatment of various infections since ancient times. This study, was aimed to investigate antimicrobial activity potential of GL against Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Candida glabrata, Candida krusei, and Candida parapsilopsis. Furthermore, it was also aimed to evaluate the toxicity potential of GL. Antimicrobial activities were screened by using microbroth dilution method...
September 2017: Pakistan Journal of Pharmaceutical Sciences
Cameron Parsons, Ben Costolo, Phillip Brown, Sophia Kathariou
Listeria monocytogenes raises major food safety and public health concerns due its potential for severe foodborne disease and persistent colonization of food processing facilities. Copper is often employed to control pathogens in agriculture and is increasingly used in healthcare facilities, but mechanisms mediating tolerance of L. monocytogenes to copper remain poorly understood. A mariner-based mutant library of L. monocytogenes 2011L-2858, implicated in the 2011 listeriosis outbreak via whole cantaloupe, was screened for growth at sublethal levels of copper yielding mutant G2B4 with decreased copper tolerance...
October 4, 2017: FEMS Microbiology Letters
Sarengaowa, Wenzhong Hu, Aili Jiang, Zhilong Xiu, Ke Feng
BACKGROUND: Food preservation is critical for keeping fresh-cut products fresh, nutritious, safe, attractive and available for consumers. To improve the safety and quality of fresh-cut fruits, fifteen essential oils (EOs) were screened to test the antimicrobial activity against Listeria monocytogenes (LM), Salmonella typhimurium (ST), Staphylococcus aureus (SA) and Escherichia coli O157:H7 (EC O157:H7). The effect of alginate-based edible coating (EC) incorporating with different concentrations thyme oil on fresh-cut Red Fuji apples was investigated...
October 9, 2017: Journal of the Science of Food and Agriculture
Tarik Harit, Reda Bellaouchi, Yahya Rokni, Abdelkhalek Riahi, Fouad Malek, Abdeslam Asehraou
The synthesis and characterization of new N-donor bitriazolic tripods were reported. The in vitro antibacterial and antifungal activities of these products were screened against fungal strain (Candida pelliculosa) and against four bacterial strains (Micrococcus luteus, Bacillus subtilis, Listeria innocua, and Escherichia coli). Biological data revealed the effect of the chemical structure on antimicrobial activity. Molecular docking studies of some compounds showed that they could act as inhibitors for the biotin carboxylase enzyme...
December 2017: Chemistry & Biodiversity
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