Fusobacterium nucleatum plays a key role in creating the pathogenic subgingival biofilm that initiates destructive periodontitis. It is also a common resident of the human gastrointestinal tract and ...has been associated with inflammatory bowel disease. The aim of the present study was to investigate the effects of green and black tea extracts as well as two of their bioactive components, EGCG and theaflavins, on the growth and virulence properties of F. nucleatum. The tea extracts and components displayed various degrees of antibacterial activity that may involve damage to the bacterial cell membrane and the chelation of iron. They also prevented biofilm formation by F. nucleatum at concentrations that did not interfere with bacterial growth. In addition, the treatment of a pre-formed F. nucleatum biofilm with the green tea extract and EGCG caused a time-dependent decrease in biofilm viability. The green and black tea extracts, EGCG, and theaflavins decreased the adherence of F. nucleatum to oral epithelial cells and matrix proteins. Moreover, these tea components also attenuated F. nucleatum-mediated hemolysis and hydrogen sulfide production, two other virulence factors expressed by this bacterium. In summary, this study showed that tea polyphenols may be of interest for treating F. nucleatum-associated disorders.
The routine use of antibiotics in agriculture has contributed to an increase in drug-resistant bacterial pathogens in animals that can potentially be transmitted to humans. In 2000, the World Health ...Organization identified resistance to antibiotics as one of the most significant global threats to public health and recommended that the use of antibiotics as additives in animal feed be phased out or terminated, particularly those used to treat human infections. Research is currently being carried out to identify alternative antimicrobial compounds for use in animal production. A number of studies, mostly in vitro, have provided evidence indicating that bacteriocins, which are antimicrobial peptides of bacterial origin, may be promising alternatives to conventional antibiotics in poultry and swine production. This review provides an update on bacteriocins and their potential for use in the poultry and swine industries.
Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although ...several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development.
Le terme prépon (πρέπον) ne signifie pas seulement le convenable, mais encore la brillance - Homère l’emploie, par exemple, pour dire d’Hector qu’il « brillait » parmi les guerriers troyens (« o ...d’éprepe kai dia pantôn », Iliade, XII, 104). Prépein (Πρέπειν) se dit ici d’un héros qui parmi ses semblables se distingue, sans doute parce qu’il convient plus qu’eux à la fonction guerrière, mais surtout parce qu’il est plus éclatant. C’est la nuance métaphorique qu’il faut saisir ici. Leconte de l’Isle traduit : « Il les surpassait tous. » Mais la prééminence d’Hector n’est pas une question de taille : Hector est plus considérable que les autres, il est splendide. Selon la première définition de Socrate, le beau serait donc l’éclat d’une splendeur exubérante ; et cette traduction, voire cette interprétation, change le sens du Hippias majeur du tout au tout. La convenance concerne la bonne proportion, l’harmonie, comme Chauvet et Saisset le soulignent, en bons classicistes français du xixe siècle. Cette définition de la beauté peut éventuellement avoir un sens dans le contexte de l’art français du xviie siècle et de son académie où l’on apprenait les canons de proportion simplifiés des Italiens du xvie siècle, mais elle n’a aucun rapport avec les discussions de l’académie platonicienne.
Biofilm has been implicated in multi-drug resistant organism outbreaks following endoscopic procedures. Automated Endoscope Reprocessors (AER) are devices validated to clean and disinfect endoscopes ...per applicable standards. The ISO 15883 part 4 standard guides performance testing validation of AERs, including cleaning performance using a biofilm test soil. The standard recommends assessment of biofilm reduction using protein or carbohydrate quantification methods. The aim of this study was to assess the suitability of various quantification methods using the ISO biofilm model. The ISO 15883 part 5 biofilm test soil method was used to grow biofilm within lumens representative of endoscopes channels. The biofilm was then quantified using five methods: Crystal Violet (CV), Colony Forming Units (CFU), Total Organic Carbon (TOC), protein assay with Orthophtalaldehyde (OPA), and protein assay by micro bicinchoninic acid (μBCA). The five methods were statistically analyzed for their ability to assess biofilm reduction on samples accurately and precisely. In addition, the quantification methods were compared to demonstrate statistical equivalency, and thus their suitability for assessing biofilm cleaning performance testing of AERs.
Streptococcus suis is an important swine pathogen and emerging zoonotic agent worldwide causing meningitis, endocarditis, arthritis and septicemia. Among the 29 serotypes identified to date, serotype ...2 is mostly isolated from diseased pigs. Although several virulence mechanisms have been characterized in S. suis, the pathogenesis of S. suis infections remains only partially understood. This study focuses on the response of S. suis P1/7 to sub-inhibitory concentrations of amoxicillin. First, capsule expression was monitored by qRT-PCR when S. suis was cultivated in the presence of amoxicillin. Then, the pro-inflammatory potential of S. suis P1/7 culture supernatants or whole cells conditioned with amoxicillin was evaluated by monitoring the activation of the NF-κB pathway in monocytes and quantifying pro-inflammatory cytokines secreted by macrophages. It was found that amoxicillin decreased capsule expression in S. suis. Moreover, conditioning the bacterium with sub-inhibitory concentrations of amoxicillin caused an increased activation of the NF-κB pathway in monocytes following exposure to bacterial culture supernatants and to a lesser extent to whole bacterial cells. This was associated with an increased secretion of pro-inflammatory cytokines (CXCL8, IL-6, IL-1β) by macrophages. This study identified a new mechanism by which S. suis may increase its inflammatory potential in the presence of sub-inhibitory concentrations of amoxicillin, a cell wall-active antibiotic, thus challenging its use for preventive treatments or as growth factor.
Reprocessing reusable medical devices is crucial in the healthcare industry. To ensure patient safety, strict standards are dictated to validate thermal disinfection in automated washer-disinfectors. ...The United States Food and Drug Administration (FDA) has specific recommendations on the vegetative bacterial challenge but comparatively vague guidance on the use of a thermophilic Mycobacterium strain for thermal disinfection studies. This study aims to compare thermal resistance of Mycobacterium hassiacum and Mycobacterium terrae and determine which strain is suitable for medical device thermal disinfection validation testing in automated washer-disinfectors.
Thermal resistance was demonstrated in vitro by calculating D-values for each strain at different exposure temperatures, and correlated with actual in situ processing conditions. M. terrae was completely killed (> 7 log reduction) at temperatures above 68 °C, with D-values between 46.6 and 27.8 s at temperatures between 59.5 and 67.2 °C. M. hassiacum was completely killed (> 8 log reduction) at temperatures above 75 °C, with D-values between 82.1 and 21.7 s at temperatures ranging between 69.2 and 73.6 °C. In vitro results were correlated in a washer-disinfector performance validation setup.
Solobacterium moorei is a volatile sulfide compound (VSC)-producing Gram-positive anaerobic bacterium that has been associated with halitosis. The aim of this study was to investigate the effects of ...green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) on growth and several halitosis-related properties of S. moorei.
A microplate dilution assay was used to determine the antibacterial activity of green tea extract and EGCG against S. moorei. Their effects on bacterial cell membrane integrity were investigated by transmission electron microscopy and a fluorescence-based permeability assay. Biofilm formation was quantified by crystal violet staining. Adhesion of FITC-labeled S. moorei to oral epithelial cells was monitored by fluorometry. The modulation of β-galactosidase gene expression in S. moorei was evaluated by quantitative RT-PCR.
The green tea extract as well as EGCG inhibited the growth of S. moorei, with MIC values of 500 and 250 μg/ml, respectively. Transmission electron microscopy analysis and a permeabilization assay brought evidence that the bacterial cell membrane was the target of green tea polyphenols. Regarding the effects of green tea polyphenols on the S. moorei colonization properties, it was found that biofilm formation on EGCG-treated surfaces was significantly affected, and that green tea extract and EGCG can cause the eradication of pre-formed S. moorei biofilms. Moreover, both the green tea extract and EGCG were found to reduce the adherence of S. moorei to oral epithelial cells. The β-galactosidase activity of S. moorei, which plays a key role in VSC production, was dose-dependently inhibited by green tea polyphenols. In addition, EGCG at ½ MIC significantly decreased the β-galactosidase gene expression.
Our study brought evidence to support that green tea polyphenols possess a number of properties that may contribute to reduce S. moorei-related halitosis. Therefore, these natural compounds may be of interest to be used to supplement oral healthcare products.
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