Difference in virulence between Staphylococcus aureus isolates causing gangrenous mastitis versus subclinical mastitis in a dairy sheep flock

Staphylococcus aureus mastitis in dairy sheep ranges from subclinical mastitis to lethal gangrenous mastitis. Neither the S. aureus virulence factors nor the host-factors or the epidemiological events contributing to the different outcomes are known. In a field study in a dairy sheep farm over 21 months, 16 natural isolates of S. aureus were collected from six subclinical mastitis cases, one lethal gangrenous mastitis case, nasal carriage from eight ewes and one isolate from ambient air in the milking room. A genomic comparison of two strains, one responsible for subclinical mastitis and one for lethal gangrenous mastitis, was performed using multi-strain DNA microarrays. Multiple typing techniques (pulsed-field-gel-electrophoresis, multiple-locus variable-number, single-nucleotide polymorphisms, randomly amplified polymorphic DNA, spa typing and sas typing) were used to characterise the remaining isolates and to follow the persistence of the gangrenous isolate in ewes’ nares. Our results showed that the two strains were genetically closely related and they shared 3 615 identical predicted open reading frames. However, the gangrenous mastitis isolate carried variant versions of several genes (sdrD, clfA-B, sasA, sasB, sasD, sasI and splE) and was missing fibrinogen binding protein B (fnbB) and a prophage. The typing results showed that this gangrenous strain emerged after the initial subclinical mastitis screening, but then persisted in the flock in the nares of four ewes. Although we cannot dismiss the role of host susceptibility in the clinical events in this flock, our data support the hypothesis that S. aureus populations had evolved in the sheep flock and that S. aureus genetic variations could have contributed to enhanced virulence

Inhibition of Candida albicans yeast–hyphal transition and biofilm formation by Solidago virgaurea water extracts

International audienc

In Vitro Screening of the Antibacterial and Anti- Candida Properties of Crushed Nonantimicrobial Drugs Frequently Prescribed in Nursing Homes

International audienc

In vitro and ex vivo metabolism of diallyl disulfide, a characteristic sulfur compound of garlic, in rat.

International audienc

Detection of Epstein–Barr Virus in Periodontitis: A Review of Methodological Approaches

Periodontitis, an inflammatory condition that affects the structures surrounding the tooth eventually leading to tooth loss, is one of the two biggest threats to oral health. Beyond oral health, it is associated with systemic diseases and even with cancer risk. Obviously, periodontitis represents a major global health problem with significant social and economic impact. Recently, a new paradigm was proposed in the etiopathogenesis of periodontitis involving a herpesviral–bacterial combination to promote long-term chronic inflammatory disease. Periodontitis as a risk factor for other systemic diseases can also be better explained based on viral–bacterial etiology. Significant efforts have brought numerous advances in revealing the links between periodontitis and Epstein–Barr virus (EBV), a gamma herpesvirus ubiquitous in the adult human population. The strong evidence from these studies may contribute to the advancement of periodontitis research and the ultimate control of the disease. Advancing the periodontitis research will require implementing suitable methods to establish EBV involvement in periodontitis. This review evaluates and summarizes the existing methods that allow the detection and diagnosis of EBV in periodontitis (also applicable in a more general way to other EBV-related diseases), and discusses the feasibility of the application of innovative emerging technologies

Métabolisme du disulfure de diallyle, un composé anticancérogène de l’ail

National audienc

Triterpenoid saponins from the aerial parts of Solidago virgaurea alpestris with inhibiting activity of Candida albicans yeast-hyphal conversion

International audienceAs part of research for treatments to combat oral dryness, our evaluation of the activity of an aqueous extract of Solidago virgaurea (L.) ssp. alpestris (Asteraceae) revealed activity against Candida albicans hyphae, the pathogenic form of this yeast. Systematic bioassay-guided fractionation of this extract gave an active saponin-containing fraction from which six oleanane-type triterpenoid saponins were isolated. Three of these were isolated for the first time, as 3-O-(beta-D-glucopyranosyl-(1 -> 3)-beta-D-glucopyranosyl)-28-O-(beta-D-fucopyranosyl-(1 -> 2)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-xylopyranosyl)-polygalacic acid (virgaureasaponin 4), 3-O-(beta-D-glucopyranosyl)-28-O-(beta-D-fucopyranosyl-(1 -> 2)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-xylopyranosyl)-polygalacic acid (virgaureasaponin 5) and 3-O-(beta-D-glucopyranosyl)-28-O-(alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-(5-O-acetylapiofuranosyl-(1 -> 3)-[4-O-(3-(3-hydroxy-1-oxobutoxy)-1-oxobutyl)]-beta-D-fucopyranosyl]-polygalacic acid (virgaureasaponin 6).Their structures were established by carrying out 1D and 2D NMR experiments along with HRMS analyses. All of the six saponins were evaluated to ascertain their inhibition of C albicans yeast-hyphal conversion, and four of them showed significant inhibition

Triterpenoid saponins from the aerial parts of Solidago virgaurea alpestris with inhibiting activity of Candida albicans yeast-hyphal conversion

International audienceAs part of research for treatments to combat oral dryness, our evaluation of the activity of an aqueous extract of Solidago virgaurea (L.) ssp. alpestris (Asteraceae) revealed activity against Candida albicans hyphae, the pathogenic form of this yeast. Systematic bioassay-guided fractionation of this extract gave an active saponin-containing fraction from which six oleanane-type triterpenoid saponins were isolated. Three of these were isolated for the first time, as 3-O-(beta-D-glucopyranosyl-(1 -> 3)-beta-D-glucopyranosyl)-28-O-(beta-D-fucopyranosyl-(1 -> 2)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-xylopyranosyl)-polygalacic acid (virgaureasaponin 4), 3-O-(beta-D-glucopyranosyl)-28-O-(beta-D-fucopyranosyl-(1 -> 2)-alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-beta-D-xylopyranosyl)-polygalacic acid (virgaureasaponin 5) and 3-O-(beta-D-glucopyranosyl)-28-O-(alpha-L-rhamnopyranosyl-(1 -> 3)-beta-D-xylopyranosyl-(1 -> 4)-alpha-L-rhamnopyranosyl-(1 -> 2)-(5-O-acetylapiofuranosyl-(1 -> 3)-[4-O-(3-(3-hydroxy-1-oxobutoxy)-1-oxobutyl)]-beta-D-fucopyranosyl]-polygalacic acid (virgaureasaponin 6).Their structures were established by carrying out 1D and 2D NMR experiments along with HRMS analyses. All of the six saponins were evaluated to ascertain their inhibition of C albicans yeast-hyphal conversion, and four of them showed significant inhibition

Modelling the Potential Human Exposure to Japanese Encephalitis Virus (JEV) in Case of Introduction into Reunion Island

International audienceJapanese encephalitis virus (JEV) is a vector-borne zoonotic virus and the leading cause of human acute encephalitis in Asia. Continuous human and commercial exchanges between Southeast Asia where JE is endemic and Reunion Island increase the risk of introducing JEV on the island, where putative vectors of JEV such as Culex quinquefasciatus and amplifying hosts such as pigs are present. Each of the 255 Reunionese pig farms was assumed to harbor a Cx. quinquefasciatus population and, together with the competent hosts: pigs and poultry and noncompetent hosts: humans, dogs, and cattle, located within a radius of 1 km, formed an epidemiological unit. We used a deterministic compartmental model to investigate whether these epidemiological units could be invaded by JEV in the event of an introduction. Since the vector population size changes seasonally, we computed the basic reproduction number (R0) using vector population sizes ranging from 100 to 100,000 vectors for each of the 255 epidemiological units. The size of the potentially exposed human population was calculated in the case where the virus would be introduced in a single epidemiological unit and in the extreme case where the virus would have spread over the whole island. For a vector population of 1,000 vectors per unit, 2 out of 255 units had an R0 ≥ 1. With 50,000 vectors per unit, more than 75% (193/255) of the units had an estimated R0 ≥ 1, representing a median of approximately 2,500 potentially exposed people if JEV was introduced in a single unit, and about 140,000 potentially exposed people if JEV had expanded throughout the island. The unit located a few kilometers from the large port area of Reunion Island had an estimated R0 ≥ 1 with at least 10,000 vectors, making it a potential gateway to JEV given a virus introduction of infected vectors