Search results for "Gram Positive"

Selective decontamination of the digestive tract in adult-to-adult living related liver transplant patients: a single centre experience

2008

Validation of a novel automatic deposition of bacteria and yeasts on MALDI target for MALDI-TOF MS-based identification using MALDI Colonyst robot

2017

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) -based identification of bacteria and fungi significantly changed the diagnostic process in clinical microbiology. We describe here a novel technique for bacterial and yeast deposition on MALDI target using an automated workflow resulting in an increase of the microbes' score of MALDI identification. We also provide a comparison of four different sample preparation methods. In the first step of the study, 100 Gram-negative bacteria, 100 Gram-positive bacteria, 20 anaerobic bacteria and 20 yeasts were spotted on the MALDI target using manual deposition, semi-extraction, wet deposition onto 70% formic …

Food Processing and Foodborne Illness

2015

Food processing means manipulation of raw materials from plants or animals into food. Since agriculture and animal husbandry were established postharvest procedures were necessary to preserve for a longer time the increasing food supplies coming from the fields and domesticated animals. Food is one of the best culture medium for a lot of microorganisms and preventing food spoilage caused by enzymes and microorganisms is crucial. Deterioration of food is caused mainly by three natural processes: 1. Oxidation – vegetables after harvesting or meat after animal slaughtering get in contact with the oxygen in the air that makes them rancid and unpleasant. 2. Enzyme action – all food contains natu…

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…

Paenibacillus larvae Chitin-Degrading Protein PlCBP49 Is a Key Virulence Factor in American Foulbrood of Honey Bees

2014

Paenibacillus larvae, the etiological agent of the globally occurring epizootic American Foulbrood (AFB) of honey bees, causes intestinal infections in honey bee larvae which develop into systemic infections inevitably leading to larval death. Massive brood mortality might eventually lead to collapse of the entire colony. Molecular mechanisms of host-microbe interactions in this system and of differences in virulence between P. larvae genotypes are poorly understood. Recently, it was demonstrated that the degradation of the peritrophic matrix lining the midgut epithelium is a key step in pathogenesis of P. larvae infections. Here, we present the isolation and identification of PlCBP49, a mo…

Targeting the Sortase A Transpeptidase to Tackle Gram-positive Pathogens

2013

The virulence factors include the cell-wall associated proteins called MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) that can promote the adhesion to host proteins, for example, the fibronectin that is very common in host tissues. The cellwall associated proteins are necessary for host colonization, invasion, immune evasion and biofilm formation [4]. The biofilms, multistratified bacterial communities that grow on a biological or artificial surface, are responsible for chronic infectious diseases and for device or biomaterial associated infections, and are more resistant to host immune defence system and to conventional antibiotics [5].

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…