Search results for "LISTERIA MONOCYTOGENES"
showing 10 items of 142 documents
Biotic and abiotic soil properties influence survival of Listeria monocytogenes in soil
2013
International audience; Listeria monocytogenes is a food-borne pathogen responsible for the potentially fatal disease listeriosis and terrestrial ecosystems have been hypothesized to be its natural reservoir. Therefore, identifying the key edaphic factors that influence its survival in soil is critical. We measured the survival of L. monocytogenes in a set of 100 soil samples belonging to the French Soil Quality Monitoring Network. This soil collection is meant to be representative of the pedology and land use of the whole French territory. The population of L. monocytogenes in inoculated microcosms was enumerated by plate count after 7, 14 and 84 days of incubation. Analysis of survival pr…
Sensitivity to acetic acid, ability to colonize abiotic surfaces and virulence potential of Listeria monocytogenes EGD-e after incubation on parsley …
2010
International audience; Abstract Aim: To investigate how the survival of Listeria monocytogenes on parsley leaves may affect its ability to sustain process-related harsh conditions and its virulence. Methods and Results: Parsley seedlings were spot inoculated with stationary phase cells of L. monocytogenes EGD-e and incubated for 15 days. Each day, bacterial cells were harvested and enumerated, and their ability to survive acetic acid challenge (90 min, pH 4.0), to colonize abiotic surfaces and to grow as biofilms was assessed. After a 3-log decrease over the first 48 h, the population stabilized to about 10(6) CFU g(-1) until the sixth day. After the sixth day, L. monocytogenes was no long…
Valutazione in vitro di bacteriocin-like inhibitory substances prodotte da batteri lattici isolati da formaggi tradizionali siciliani
2015
I batteri lattici (LAB) sono in grado di produrre differenti sostanze antimicrobiche tra cui le batteriocine, sostanze di natura proteica che stanno riscuotendo un crescente interesse per il loro possibile impiego come bio-conservanti per controllare e contenere i microrganismi indesiderati responsabili di contaminazioni e/o deterioramento delle matrici alimentari. Gli autori descrivono i risultati di uno screening volto all’identificazione di bacteriocin-like inhibitory substances (BLIS) prodotte da LAB isolati da processi produttivi di formaggi tradizionali siciliani utilizzando due metodi di screening e valutando la natura proteica delle sostanze antimicrobiche eventualmente prodotte, me…
Analysis of Multilocus Sequence Typing and Virulence Characterization of Listeria monocytogenes Isolates from Chinese Retail Ready-to-Eat Food
2016
Eighty Listeria monocytogenes isolates were obtained from Chinese retail ready-to-eat (RTE) food and were previously characterized with serotyping and antibiotic susceptibility tests. The aim of this study was to characterize the subtype and virulence potential of these L. monocytogenes isolates by multilocus sequence typing (MLST), virulence-associate genes, epidemic clones (ECs), and sequence analysis of the important virulence factor: internalin A (inlA). The result of MLST revealed that these L. monocytogenes isolates belonged to 14 different sequence types (STs). With the exception of four new STs (ST804, ST805, ST806, and ST807), all other STs observed in this study have been associat…
Characterisation of the microflora contaminating the wooden vats used for traditional Sicilian cheese production
2015
Traditional Sicilian cheese productions are carried out employing traditional wooden vats, called <em>tina.</em> Many studies have highlighted the beneficial role of wooden dairy equipment by contributing to enriching the milk microflora and improving the acidification processes. The present work was undertaken to evaluate the safety of the wooden vats used to coagulate milk. To this purpose, the different microbial populations hosted onto the internal surfaces of the vats used to produce two different stretched cheeses, namely <em>Caciocavallo Palermitano</em> and <em>Vastedda della valle del Belìce DOP</em>, were investigated for the presence of spoilag…
Evidence of autoinduction heterogeneity via expression of the agr system of listeria monocytogenes at the single-cell level
2011
ABSTRACT To investigate if the primary function of the Agr system of Listeria monocytogenes is to monitor cell density, we followed Agr expression in batch cultures, in which the autoinducer concentration was uniform, and in biofilms. Expression was heterogeneous, suggesting that the primary function of Agr is not to monitor population density.
Changes in gene expression during adaptation of Listeria monocytogenes to the soil environment
2011
project SEST 009; International audience; Listeria monocytogenes is a ubiquitous opportunistic pathogen responsible for listeriosis. In order to study the processes underlying its ability to adapt to the soil environment, whole-genome arrays were used to analyse transcriptome modifications 15 minutes, 30 minutes and 18 h after inoculation of L. monocytogenes EGD-e in soil extracts. Growth was observed within the first day of incubation and large numbers were still detected in soil extract and soil microcosms one year after the start of the experiment. Major transcriptional reprofiling was observed. Nutrient acquisition mechanisms (phosphoenolpyruvate-dependent phosphotransferase systems and…
Listeria monocytogenes izplatība auksti kūpinātās zivīs derīguma termiņa ietvaros
2017
Maģistra darba praktiskā daļa izstrādāta Pārtikas drošības, dzīvnieku veselības un vides zinātniskajā institūtā „BIOR”. Darba mērķis bija novērtēt Listeria monocytogenes izplatību auksti kūpinātu (a/k) zivju produktos to derīguma termiņa ietvaros¬. Lai izvērtētu risku, kāds varētu rasties lietojot šos pārtikas produktus, tika noteikta L. monocytogenes klātbūtne un skaits (KVV/g). Darba gaitā tika iegādāti 37 dažādi a/k zivju produkti, no katra zivju produkta pērkot divus iepakojumus, trīs dažādās partijās, atkārtojumu veikšanai. No pārbaudītajiem 222 paraugiem maksimāli pieļaujamo robežvērtību (100 KVV/g) pārsniedza viens paraugs, savukārt L. monocytogenes izplatība a/k vakuumētās zivīs bij…
Listeria monocytogenes izplatība auksti kūpinātās vakuumā iepakotās zivīs un uzglabāšanas temperatūras ietekme derīguma termiņa ietvaros
2015
Listerioze tiek uzskatīta par jaunu slimību un par to pirmo reizi veica pētījumus 20. gs pirmajā pusē. Pēc Latvijas slimību un kontroles centra sniegtās informācijas, listerioze ir reta slimība, jo Eiropā uz miljons iedzīvotājiem gadā tiek reģistrēti vidēji 2 - 7 saslimšanas gadījumi. Kā būtisks faktors jāmin tas, ka ne visās valstīs tiek veikta saslimšanas gadījumu reģistrācija. Visplašāk listeriozes mikrobioloģisko diagnostiku veic Francijā, kur notiek plaši izmeklējumi gan pārtikas produktiem, gan klīniskajiem materiāliem. Listeria monocytogenes ģints baktērijas ir bieži sastopamas apkārtējā vidē, ūdenī, augsnē, veģetācijā un dzīvnieku izkārnījumos. Grampozitīvā baktērija Listeria monocy…
Listeria monocytogenes
2017
Prod 2017-266 équipe EA UB BIOME; National audience; résumé du livre : Pour garantir et maîtriser la sécurité microbiologique des aliments et prévenir les crises sanitaires alimentaires, la connaissance et la surveillance des microorganismes pathogènes depuis la production primaire jusqu’à la distribution des denrées alimentaires en passant par la transformation, sont indispensables. Cet ouvrage de référence traite des dangers microbiologiques alimentaires majeurs (microorganismes infectieux ou toxines d’origine microbienne) et des risques associés pour l’Homme. Illustré de nombreux schémas et tableaux de synthèse, il fait un point complet sur les notions fondamentales de microbiologie géné…