Low MRSA prevalence in horses at farm level

Background: In Europe, methicillin-resistant Staphylococcus aureus (MRSA) belonging to the clonal complex (CC) 398 has become an important pathogen in horses, circulating in equine clinics and causing both colonization and infection. Whether equine MRSA is bound to hospitals or can also circulate in the general horse population is currently unknown. This study, therefore, reports the nasal and perianal MRSA screening of 189 horses on 10 farms in a suspected high prevalence region (East-and West-Flanders, Belgium). Results: Only one horse (0.53%) from one farm (10%) tested positive in the nose. It carried a spa type t011-SCCmecV isolate, resistant to beta-lactams and tetracycline, which is typical for livestock-associated MRSA CC398. Conclusion: In the region tested here, horses on horse farms seem unlikely to substantially contribute to the large animal associated ST398 MRSA reservoir present at intensive animal production units

Mometasone furoate and fluticasone furoate are equally effective in restoring nasal epithelial barrier dysfunction in allergic rhinitis

Rinitis alérgica; Integridad epitelial; Furoato de mometasonaRinitis al·lèrgica; Integritat epitelial; Furoat de mometasonaAllergic rhinitis; Epithelial integrity; Mometasone furoateTight junction defects (TJ) have been associated with a defective epithelial barrier function in allergic rhinitis (AR). Intranasal corticosteroids are potent drugs frequently used to treat AR and are shown to restore epithelial integrity by acting on TJs and by reducing type 2 cytokine production. However, the effect of different classes of intranasal corticosteroids on the epithelial barrier has not been studied. Therefore, we compared the effect of 2 intranasal corticosteroids, ie, fluticasone furoate (FF) and mometasone furoate (MF) on epithelial barrier function. Both FF and MF similarly increased trans-epithelial electrical resistance of primary nasal epithelial cell cultures from AR patients. In a house dust mite-induced allergic asthma mouse model, FF and MF had similar beneficial effects on fluorescein isothiocyanate–dextran 4 kDa mucosal permeability, eosinophilic infiltration and IL-13 levels. Both molecules increased mRNA expression of the TJ proteins occludin and zonula occludens-1, thereby restoring epithelial barrier function. Lastly, we showed that long-term FF treatment also increased expression of occludin in AR patients compared to controls. In conclusion, both FF and MF effectively restore epithelial barrier function by increasing expression of TJ proteins in AR patients.This work was supported by an unrestricted grant from GSK. BS is supported by the Fund for Scientific Research Flanders (FWO), Belgium

Body size and dispersal mode as key traits determining metacommunity structure of aquatic organisms

Relationships between traits of organisms and the structure of their metacommunities have so far mainly been explored with meta-analyses. We compared metacommunities of a wide variety of aquatic organism groups (12 groups, ranging from bacteria to fish) in the same set of 99 ponds to minimise biases inherent to meta-analyses. In the category of passive dispersers, large-bodied groups showed stronger spatial patterning than small-bodied groups suggesting an increasing impact of dispersal limitation with increasing body size. Metacommunities of organisms with the ability to fly (i.e. insect groups) showed a weaker imprint of dispersal limitation than passive dispersers with similar body size. In contrast, dispersal movements of vertebrate groups (fish and amphibians) seemed to be mainly confined to local connectivity patterns. Our results reveal that body size and dispersal mode are important drivers of metacommunity structure and these traits should therefore be considered when developing a predictive framework for metacommunity dynamics

Lactobacilli have a niche in the human nose

Although an increasing number of beneficial microbiome members are characterized for the human gut and vagina, beneficial microbes are underexplored for the human upper respiratory tract (URT). In this study, we demonstrate that taxa from the beneficial Lactobacillus genus complex are more prevalent in the healthy URT than in patients with chronic rhinosinusitis (CRS). Several URT-specific isolates are cultured, characterized, and further explored for their genetic and functional properties related to adaptation to the URT. Catalase genes are found in the identified lactobacilli, which is a unique feature within this mostly facultative anaerobic genus. Moreover, one of our isolated strains, Lactobacillus casei AMBR2, contains fimbriae that enable strong adherence to URT epithelium, inhibit the growth and virulence of several URT pathogens, and successfully colonize nasal epithelium of healthy volunteers. This study thus demonstrates that specific lactobacilli are adapted to the URT and could have a beneficial keystone function in this habitat

The effect of the microbiome on nasal epithelial barrier function in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is characterized by mucosal inflammation in the nasal cavity and the paranasal sinuses and effects approximately 11% of the European population. CRS is generally devided into two phenotypes depending on the presence or absence of nasal polyps, namely CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Despite the available treatment strategies, up to 40% of CRS patients remain uncontrolled even after surgery. As such there is an urgent need to identify endotypes of CRS to develop patient's tailored strategies. Recently, a defective epithelial barrier, as a result of decreased tight junction (TJ) function, has been found in CRS. TJs are intercellular junctions that play an important role in maintaining an intact epithelial barrier and protect the human body from penetration of pathogens and allergens. Hence, restoring/preserving epithelial barrier function migth play a key role in the treatment of CRS. Additionally, a dysregulated microbiome is also found in the etiology of CRS. Variou pathogenic bacteria have been associated with the pathology of CRS and can disrupt airway epithelial barrier integrity. However, microorganism can also induce beneficial effects to the host. These bacteria are called probiotics and can provide health benefits to the host when they are administered in adequate amounts. Traditionally, lactobacilli have been used as probiotics and various studies have shown that lactobacilli are normal inhibitants of the healthy upper respiratory tract. However, evidence of the regulatory properties of lactobacilli on airway epithelial cells is limited. Lactobacilli can modulate host immune responses by interacting with pattern recognition receptors, such as Toll-like receptors, present on nasal epithelial barrier. In this PhD project, the microbiome in CRS patients is studied in relation to CRS pheno- and endotypes. Furthermore, the effect of Lactobacillus casei AMB-R2 on epithelial cells is investigated in healthy controls and patients with CRSwNP. Additionally, the potential beneficial effects of this species on barrier function are exerted through activation of TLR2 signaling in CRSwNP.status: publishe

Taste Receptors: The Gatekeepers of the Airway Epithelium

Taste receptors are well known for their role in the sensation of taste. Surprisingly, the expression and involvement of taste receptors in chemosensory processes outside the tongue have been recently identified in many organs including the airways. Currently, a clear understanding of the airway-specific function of these receptors and the endogenous activating/inhibitory ligands is lagging. The focus of this review is on recent physiological and clinical data describing the taste receptors in the airways and their activation by secreted bacterial compounds. Taste receptors in the airways are potentially involved in three different immune pathways (i.e., the production of nitric oxide and antimicrobial peptides secretion, modulation of ciliary beat frequency, and bronchial smooth muscle cell relaxation). Moreover, genetic polymorphisms in these receptors may alter the patients’ susceptibility to certain types of respiratory infections as well as to differential outcomes in patients with chronic inflammatory airway diseases such as chronic rhinosinusitis and asthma. A better understanding of the function of taste receptors in the airways may lead to the development of a novel class of therapeutic molecules that can stimulate airway mucosal immune responses and could treat patients with chronic airway diseases