Search results for "MONOCYTOGENE"

Isolation, identification and characterisation of three novel probiotic strains (Lactobacillus paracaseiCNCM I-4034,Bifidobacterium breveCNCM I-4035 …

2013

The aim of the present study was to isolate, identify and characterise novel strains of lactic acid bacteria and bifidobacteria with probiotic properties from the faeces of exclusively breast-fed infants. Of the 4680 isolated colonies, 758 exhibited resistance to low pH and tolerance to high concentrations of bile salts; of these, only forty-two exhibited a strong ability to adhere to enterocytesin vitro.The identities of the isolates were confirmed by 16S ribosomal RNA (rRNA) sequencing, which permitted the grouping of the forty-two bacteria into three different strains that showed more than 99 % sequence identity withLactobacillus paracasei,Lactobacillus rhamnosusandBifidobacterium breve,…

Macrophage inhibiting activity in serum and central lymph of Listeria-immune mice.

1975

Serum and central lymph from mice immunized with live Listeria monocytogenes six days previously and boostered four hours before collection exerted significant inhibition of macrophage migration in vitro. It is concluded that lymphokines or lymphokine-like products of the cellular immune reaction are released in vivo and are possibly instrumental in the generation of acquired cellular antibacterial immunity.

Listeria species in raw and ready-to-eat foods from restaurants.

2001

From September 1999 to March 2000, meat (pork, beef, and chicken), fish (salmon, hake, and sole), vegetable (lettuce and spinach), and Spanish potato omelette samples obtained at restaurants were collected and tested for the occurrence of Listeria spp. Listeria monocytogenes was isolated from 3 (2.9%) out of 103 studied samples. Other species isolated were Listeria grayi (13.6%), Listeria innocua (1.9%), Listeria ivanovii (5.8%), Listeria seeligeri (3.9%), and Listeria welshimeri (1.9%). Listeria was neither isolated from beef nor any type of fish.

Listeria monocytogenes Differential Transcriptome Analysis Reveals Temperature-Dependent Agr Regulation and Suggests Overlaps with Other Regulons

2012

Listeria monocytogenes is a ubiquitous, opportunistic pathogenic organism. Environmental adaptation requires constant regulation of gene expression. Among transcriptional regulators, AgrA is part of an auto-induction system. Temperature is an environmental cue critical for in vivo adaptation. In order to investigate how temperature may affect AgrA-dependent transcription, we compared the transcriptomes of the parental strain L. monocytogenes EGD-e and its Delta agrA mutant at the saprophytic temperature of 25 degrees C and in vivo temperature of 37 degrees C. Variations of transcriptome were higher at 37 degrees C than at 25 degrees C. Results suggested that AgrA may be involved in the regu…

2020

Microbial communities are continuously exposed to the arrival of alien species. In complex environments such as soil, the success of invasion depends on the characteristics of the habitat, especially the diversity and structure of the residing bacterial communities. While most data available on microbial invasion relies on experiments run under constant conditions, the fate of invading species when the habitat faces disturbances has not yet been addressed. Here, we designed experiments to assess the consequences of habitat disturbance on the success of ongoing microbial invasion. We investigated (i) if disturbance-induced alterations in resident microbial communities could mitigate or facil…

Nation-wide study of the occurrence of Listeria monocytogenes in French soils using culture-based and molecular detection methods

2013

Identifiant HAL : hal-01120618; International audience; Soil is a potential reservoir of human pathogens and a possible source of contamination of animals, crops and water. In order to study the distribution of Listeria monocytogenes in French soils, a real-time PCR TaqMan assay targeting the phosphoribosylpyrophosphate synthetase (prs) gene of L. monocytogenes was developed for the specific detection and quantification of this bacterium within a collection of 1315 soil DNAs originated from the French Soil Quality Monitoring Network. The prs real-time PCR TaqMan assay was specific for L. monocytogenes and could quantify accurately down to 104L. monocytogenes per gram of dry soil. Among the …

Listeria monocytogenes, a down-to-earth pathogen

2013

International audience; Listeria monocytogenes is the causative agent of the food-borne life threatening disease listeriosis. This pathogenic bacterium received much attention in the endeavor of deciphering the cellular mechanisms that underlie the onset of infection and its ability to adapt to the food processing environment. Although information is available on the presence of L. monocytogenes in many environmental niches including soil, water, plants, foodstuff and animals, understanding the ecology of L. monocytogenes in outdoor environments has received less attention. Soil is an environmental niche of pivotal importance in the transmission of this bacterium to plants and animals. Soil…

Characterization of Listeria monocytogenes isolates from human listeriosis cases in Italy.

2009

ABSTRACT The objective of this study was to characterize by serotyping, pulsed-field gel electrophoresis (PFGE), and PCR amplification of virulence genes and markers of epidemic clones I, II, and III (ECI, ECII, and ECIII) 54 human isolates from apparently sporadic cases of infection occurring in the Lombardy region and in the province of Florence, Tuscany, Italy, in the years 1996 to 2007. Listeria monocytogenes isolates were provided by the clinical microbiology laboratories of the Lombardy region and the “Careggi” Hospital of Florence, Tuscany, Italy. Serotyping, PFGE after digestion with the AscI and ApaI enzymes, and PCR amplification for the inlA , inlC , and inlJ genes and ECI, ECII,…

Prevalence, Genetic Diversity and Factors Associated with Distribution of Listeria monocytogenes and Other Listeria spp. in Cattle Farms in Latvia

2021

Listeria spp. is a diverse genus of Gram-positive bacteria commonly present in the environment while L. monocytogenes and L. ivanovii are well known human and ruminant pathogens. The aim of the present study was to reveal the prevalence and genetic diversity of L. monocytogenes and other Listeria spp. and to identify the factors related to the abundance of pathogen at cattle farms. A total of 521 animal and environmental samples from 27 meat and dairy cattle farms were investigated and the genetic diversity of L. monocytogenes isolates was studied with WGS. The prevalence of Listeria was 58.9%, while of L. monocytogenes it was −11%. The highest prevalence of L. monocytogenes was found in th…

Biofilm formation of listeria monocytogenes strains under food processing environments and pan-genome-wide association study

2019

International audience; Concerns about food contamination by Listeria monocytogenes are on the rise with increasing consumption of ready-to-eat foods. Biofilm production of L. monocytogenes is presumed to be one of the ways that confer its increased resistance and persistence in the food chain. In this study, a collection of isolates from foods and food processing environments (FPEs) representing persistent, prevalent, and rarely detected genotypes was evaluated for biofilm forming capacities including adhesion and sessile biomass production under diverse environmental conditions. The quantity of sessile biomass varied according to growth conditions, lineage, serotype as well as genotype bu…