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Listeria monocytogenes

H W Kim, Y J Hong, J I Jo, S D Ha, S H Kim, H J Lee, M S Rhee
Microbiological quality of 206 raw ready-to-eat seafood samples were investigated according to species (gizzard shad, halibut, rockfish, tuna, oyster, and squid) and distribution channels (fishery, hyper, and online market). Enumeration of Aerobic Plate Count (APC) and total coliforms (TC) and pathogenic bacteria (Bacillus cereus, Staphylococcus aureus, and Vibrio parahaemolyticus) were performed, and level of microbiological quality were classified into four groups: satisfactory, acceptable, unsatisfactory, and unacceptable...
October 16, 2016: Letters in Applied Microbiology
Yosra Ben-Fadhel, Sabrina Saltaji, Mohamed Ali Khlifi, Stephane Salmieri, Khanh Dang Vu, Monique Lacroix
The antimicrobial activity of essential oils (EOs), organic acid (OA) salts and natamycin, a natural antifungal produced during fermentation by the bacterium Streptomyces natalensis, was assessed against four pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Aspergillus niger). The Minimum Inhibitory Concentration (MIC) of each antimicrobial (AM) was assessed to determine their efficiency on tested microbial species in order to select the most efficient. Then, the interactions between different antimicrobial compounds showing the lowest MIC were determined by the checkerboard method...
October 11, 2016: International Journal of Food Microbiology
Yi Chen, Régis Pouillot, Laurel S Burall, Errol A Strain, Jane M Van Doren, Antonio J De Jesus, Anna Laasri, Hua Wang, Laila Ali, Aparna Tatavarthy, Guodong Zhang, Lijun Hu, James Day, Ishani Sheth, Jihun Kang, Surasri Sahu, Devayani Srinivasan, Eric W Brown, Mickey Parish, Donald L Zink, Atin R Datta, Thomas S Hammack, Dumitru Macarisin
A precise and accurate method for enumeration of low level of Listeria monocytogenes in foods is critical to a variety of studies. In this study, paired comparison of most probable number (MPN) and direct plating enumeration of L. monocytogenes was conducted on a total of 1730 outbreak-associated ice cream samples that were naturally contaminated with low level of L. monocytogenes. MPN was performed on all 1730 samples. Direct plating was performed on all samples using the RAPID'L.mono (RLM) agar (1600 samples) and agar Listeria Ottaviani and Agosti (ALOA; 130 samples)...
September 26, 2016: International Journal of Food Microbiology
Jeeyeon Lee, Eunji Gwak, Heeyoung Lee, Jimyeong Ha, Soomin Lee, Sejeong Kim, Mi-Hwa Oh, Beom-Young Park, Kyoung-Hee Choi, Yohan Yoon
Objective: The objective of this study was to evaluate the effect of combinations of NaNO2 and NaCl concentrations on Listeria monocytogenes growth in emulsion-type sausage. Methods: Sausages formulated with different combinations of NaNO2 (0 and 10 ppm) and NaCl (1.0%, 1.25% and 1.5%) were inoculated with a five-strain L. monocytogenes mixture, and stored at 4oC, 10oC or 15oC, under aerobic or vacuum conditions. L. monocytogenes cell counts were measured at appropriate intervals, and kinetic parameters such as growth rate and lag phase duration (LPD) were calculated using the modified Gompertz model...
October 5, 2016: Asian-Australasian Journal of Animal Sciences
Julien Karim Malet, Pascale Cossart, David Ribet
Bacterial pathogens can interfere during infection with host cell organelles, such as mitochondria, the endoplasmic reticulum-Golgi system or nuclei. As important cellular functions are often compartmentalized in these organelles, their targeting allows pathogens to manipulate key host functions during infection. Here, we identify lysosomes as a new class of organelles targeted by the pathogenic bacterium Listeria monocytogenes. We demonstrate that extracellular Listeria, via secretion of the pore-forming toxin Listeriolysin O (LLO), alter lysosomal integrity in epithelial cells, but not in macrophages...
October 14, 2016: Cellular Microbiology
N A Jarvis, J R Donaldson, C A O'Bryan, S C Ricke, P G Crandall
Listeria monocytogenes can be carried by and infect poultry, although the clinical disease in birds is rare. Escape from macrophage phagocytosis is a key step in pathogenesis for L. monocytogenes Therefore, we investigated the infection of the chicken macrophage-like cell line HD11 with 2 strains of L. monocytogenes EGD-e and Scott A. After infection, L. monocytogenes was quantified by spread plating and HD11 was quantified with trypan blue exclusion stain before enumeration. The standard macrophage killing protocols require washing the cell monolayers 3 times with PBS, which was found to negatively influence HD11 monolayers...
October 12, 2016: Poultry Science
Lindsay Liang, Saravanamuttu Gnaneshan, Rafael A Garduño, Gustavo V Mallo
Mobile genetic elements in bacteria, such as plasmids, act as important vectors for the transfer of antibiotic resistance, virulence, and metal resistance genes. Here, we report the genome sequence of a new plasmid pLM-C-273, identified in a Listeria monocytogenes strain isolated from a clinical sample in Ontario, Canada.
October 13, 2016: Genome Announcements
Cristina Faralla, Gabrielle A Rizzuto, David E Lowe, Byoungkwan Kim, Cara Cooke, Lawrence R Shiow, Anna I Bakardjiev
Intrauterine infection is a major detriment for maternal-child health and occurs despite local mechanisms that protect the maternal-fetal interface from a wide variety of pathogens. The bacterial pathogen Listeria monocytogenes causes spontaneous abortion, stillbirth, and preterm labor in humans, and serves as a model for placental pathogenesis. Given the unique immunological environment of the maternal-fetal interface we hypothesized that virulence determinants with placental tropism are required for infection of this tissue...
October 10, 2016: Infection and Immunity
Jiangwei Yao, Megan E Ericson, Matthew W Frank, Charles O Rock
Enoyl-acyl carrier protein reductase catalyzes the last step in each elongation cycle of type II bacterial fatty acid synthesis and is a key regulatory protein in bacterial fatty acid synthesis. The facultative intracellular pathogen Listeria monocytogenes encodes two functional enoyl-ACP isoforms based on their ability to complement the temperature-sensitive growth phenotype of E. coli strain JP1111 (fabI(Ts)). The FabI isoform was inactivated by the FabI selective inhibitor AFN-1252, but the FabK isoform was not affected by the drug as expected...
October 10, 2016: Infection and Immunity
Fengying Dai, Miao Zhang, Dixin Xu, Yin Yang, Jiaxiao Wang, Mingzhen Li, Meihong Du
Micro- and nano-immunomagnetic beads (MIMBs and NIMBs) used for immunomagnetic separation (IMS) with Polymerase Chain Reaction (PCR) were studied for the rapid detection of Salmonella. The capture efficiency of the two different IMBs was evaluated by a conventional plate counting method, and the binding pattern was studied by scanning electron microscopy. The specificity of the IMBs was tested with Salmonella, Shigella flexneri, Enterhemorrhagic Escherichia coli O157:H7(EHEC O157:H7) and Listeria monocytogenes...
October 12, 2016: Biotechnology and Applied Biochemistry
Helena Pillich, Madhu Puri, Trinad Chakraborty
Listeria monocytogenes is a ubiquitously occurring gram-positive bacterium in the environment that causes listeriosis, one of the deadliest foodborne infections known today. It is a versatile facultative intracellular pathogen capable of growth within the host's cytosolic compartment. Following entry into the host cell, L. monocytogenes escapes from vacuolar compartments to the cytosol, where the bacterium begins a remarkable journey within the host cytoplasm, culminating in bacterial spread from cell to cell, to deeper tissues and organs...
September 21, 2016: Current Topics in Microbiology and Immunology
Yuko Yoshikawa, Yoshitsugu Ochiai, Mariko Mochizuki, Osamu Fujita, Takashi Takano, Ryo Hondo, Fukiko Ueda
Pulse field gel electrophoresis (PFGE) is widely used for listeriosis surveillance. Although this technique is effective for epidemiology, the data among laboratories are inconsistent. We previously reported a method for L. monocytogenes subtyping combined with sequence analysis of partial iap and whole genome restriction fragment length polymorphism (RFLP) using XbaI, ClaI (BanIII) and PstI. However, distinguishing subtypes was challenging, because the output comprised complicated fragment patterns. In this study, we aimed to establish a simple genotyping method that does not depend on visual observation, rather it focuses on multi-locus sequence typing (MLST) using three genes, iap, sigB and actA...
October 1, 2016: Journal of Veterinary Medical Science
S Bertrand, P J Ceyssens, M Yde, K Dierick, F Boyen, J Vanderpas, R Vanhoof, W Mattheus
Listeriosis is a rare but severe disease, mainly caused by Listeria monocytogenes. This study shows the results of the laboratory-based surveillance of Listeriosis in Belgium over the period 1985-2014. Besides the incidence and some demographic data we present also more detailed microbiological and molecular characteristics of human strains isolated since 2000. The strains from the latter period were compared to food and animal strains from the same period. Our study shows that different food matrices were commonly contaminated with L...
2016: PloS One
Alexandra Moura, Alexis Criscuolo, Hannes Pouseele, Mylène M Maury, Alexandre Leclercq, Cheryl Tarr, Jonas T Björkman, Timothy Dallman, Aleisha Reimer, Vincent Enouf, Elise Larsonneur, Heather Carleton, Hélène Bracq-Dieye, Lee S Katz, Louis Jones, Marie Touchon, Mathieu Tourdjman, Matthew Walker, Steven Stroika, Thomas Cantinelli, Viviane Chenal-Francisque, Zuzana Kucerova, Eduardo P C Rocha, Celine Nadon, Kathie Grant, Eva M Nielsen, Bruno Pot, Peter Gerner-Smidt, Marc Lecuit, Sylvain Brisse
Listeria monocytogenes (Lm) is a major human foodborne pathogen. Numerous Lm outbreaks have been reported worldwide and associated with a high case fatality rate, reinforcing the need for strongly coordinated surveillance and outbreak control. We developed a universally applicable genome-wide strain genotyping approach and investigated the population diversity of Lm using 1,696 isolates from diverse sources and geographical locations. We define, with unprecedented precision, the population structure of Lm, demonstrate the occurrence of international circulation of strains and reveal the extent of heterogeneity in virulence and stress resistance genomic features among clinical and food isolates...
October 10, 2016: Nature Microbiology
D C Aryani, M H Zwietering, H M W den Besten
Microbial growth and inactivation kinetics in food can be predicted when the effects of food properties and environmental conditions on microbial responses are available. However the effects of these intrinsic and extrinsic variables on microbial kinetics are often obtained using laboratory media, and deviations between predictions and true behaviour might occur if the specific effect of a food product is not known or considered in the prediction. Therefore, knowing the food specific effect on microbial kinetics might not only result in a more realistic growth and inactivation prediction, but also extend the knowledge on factors influencing growth and heat resistance...
September 21, 2016: International Journal of Food Microbiology
Jorge Pinheiro, Olga Reis, Ana Vieira, Ines M Moura, Luisa Zanolli Moreno, Filipe Carvalho, M Graciela Pucciarelli, Francisco García-Del Portillo, Sandra Sousa, Didier Cabanes
Bacterial pathogenicity deeply depends on the ability to secrete virulence factors that bind specific targets on host cells and manipulate host responses. The Gram-positive bacterium Listeria monocytogenes is a human foodborne pathogen that remains a serious public health concern. To transport proteins across its cell envelope, this facultative intracellular pathogen engages a set of specialized secretion systems. Here we show that L. monocytogenes EGDe uses a specialized secretion system, named ESX-1, to secrete EsxA, a homologue of the virulence determinants ESAT-6 and EsxA of Mycobacterium tuberculosis and Staphylococcus aureus, respectively...
October 10, 2016: Virulence
Vivek Sharma, Taranpreet Kaur, Helen Bridle, Moushumi Ghosh
This study evaluated five extracellular polymers of bacterial origin possessing mucoadhesive properties for their antimicrobial properties and toxicological characteristics. Of the five tested mucoadhesive biopolymers, the extracellular polymer produced by a strain of Acinetobacter haemolyticus exhibited broad antimicrobial efficacy towards Yersinia enterocolitica, Salmonella typhimurium, Listeria monocytogenes, Escherichia coli O157:H7 and Bacillus subtilis. Significant (p<0.05) inhibition of gram negative bacterial pathogens followed by gram positives were observed with the biopolymer at a dose of 40-60μg ml-1 at ambient temperature...
October 6, 2016: International Journal of Biological Macromolecules
Hae In Yong, Haelim Lee, Sanghoo Park, Jooyoung Park, Wonho Choe, Samooel Jung, Cheorun Jo
The aims of the present study were to examine the use of a flexible thin-layer plasma system in inactivating bacteria and mold on beef jerky in a commercial package and to evaluate the physicochemical changes of the jerky. After plasma treatment for 10min, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Aspergillus flavus populations on the beef jerky were reduced by approximately 2 to 3Log CFU/g. No significant changes in metmyoglobin content, shear force, and myofibrillar fragmentation index were found in the plasma-treated beef jerky...
September 30, 2016: Meat Science
Piumi De Abrew Abeysundara, Ramakrishna Nannapaneni, Kamlesh A Soni, Chander S Sharma, Barakat Mahmoud
Food processing and food handling environments may contain residual levels of sanitizers or cleaners which may trigger oxidative stress adaptation in Listeria monocytogenes. The aim of this study was to determine the induction and stability of oxidative stress adaptation in L. monocytogenes EGD (Bug600) (serotype 1/2a) and F1057 (serotype 4b) at different concentrations and times of sublethal oxidative stress induced by H2O2 or sublethal alkali stress induced by NaOH at 37°C. Both L. monocytogenes Bug600 and F1057 strains showed significantly higher survival in lethal oxidative stress (1000ppm H2O2) after pre-exposure to 50ppm H2O2 for 30min compared to control cells (no pre-exposure to H2O2)...
September 29, 2016: International Journal of Food Microbiology
Léna Barre, Apostolos S Angelidis, Djouher Boussaid, Emilie Decourseulles Brasseur, Eléonore Manso, Nathalie Gnanou Besse
During the past six years, new species of the genus Listeria have been isolated from foods and other environmental niches worldwide. The Standard method EN ISO 11290-1 that is currently under revision will include in its scope all Listeria species in addition to L. monocytogenes. The objective of this project was to evaluate the ability of the Standard EN ISO 11290-1 method to detect and identify the newly discovered Listeria spp., and to assess potential over-growth effects of the new species in mixed cultures with L...
September 28, 2016: International Journal of Food Microbiology
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