Impact of the COVID-19 pandemic on tuberculosis national reference laboratory services in the WHO European Region, March to November 2020

We assessed the impact of COVID-19 on diagnostic services for tuberculosis (TB) by national reference laboratories in the WHO European Region. Of 35 laboratories, 30 reported declines in TB sample numbers, amounting up to > 50% of the pre-COVID-19 volumes. Sixteen reported reagent or consumable shortages. Nineteen reallocated ressources to SARS-CoV-2 testing, resulting in an overall increase in workload, largely without a concomitant increase in personnel (n = 14). This poses a risk to meeting the 2025 milestones of the End TB Strategy.Financial support for this work has been provided by the German Government.S

Updating the approaches to define susceptibility and resistance to anti-tuberculosis agents: implications for diagnosis and treatment

11 páginas, 2 figuras, 1 tablaInappropriately high breakpoints have resulted in systematic false-susceptible AST results to anti-TB drugs. MIC, PK/PD and clinical outcome data should be combined when setting breakpoints to minimise the emergence and spread of antimicrobial resistance.I. Comas was supported by PID2019-104477RB-I00 from the Spanish Science Ministry and by ERC (CoG 101001038)Peer reviewe

Studies on the dynamics and coordination of host gene expression responses to bacterial pathogens connecting transcriptional profiles with chromosomal organization

Dans le premier chapitre de cette thèse, nous mettons en évidence l impact du pathogène invasif S. flexneri sur l organisation chromosomique de l hôte et ses effets sur les interactions chromosomiques dans les cellules épithéliales intestinales. Ce travail révèle comment S. flexneri modifie l organisation chromosomique. Nous avons également pu démontrer le rôle répressif de l effecteur bactérien injecté OspF sur la réponse de défense de l hôte au niveau des interactions chromosomiques. Par ce travail, nous avons fourni une première piste concernant la manière dont un stress environnemental, telle qu une infection bactérienne, affecte la régulation génique à l échelle de l organisation chromosomique. Dans une seconde partie de ce travail, nous avons tenté de développer une technique pour suivre l expression génique d une cellule unique en temps réel. Un tel système nous permettrait de suivre l expression génique du pathogène et de l hôte dans une seule cellule et en temps réel. Pendant ce travail, nous avons développé différents aspects de notre méthode à l échelle moléculaire. Néanmoins ces différents aspects restent en cours d élaboration pour l instant et des améliorations doivent être effectuées pour permettre leur fonctionnalité optimale. D autres études, qui ont été également menées dans le cadre de mon doctorat, ont montrées le recrutement des protéines cellulaires au cours de l infection par S. flexneri au site d entrée de la bactérie. Cette thèse, dans son ensemble, donne un nouvel aperçu sur la manière dont la bactérie pathogène S. flexneri manipule l hôte au niveau de différents compartiments cellulaires afin de faciliter le processus d infectionPARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Turning on the spotlight—using light to monitor and characterize bacterial effector secretion and translocation

International audienceSecretion and translocation of bacterial pathogen effectors into host cells via dedicated secretion machineries like type III secretion systems (T3SSs) or type IV secretion systems (T4SSs) is a key feature employed by pathogens to attack host cells. Innovative fluorescence and imaging approaches have blossomed during recent years, and became instrumental in revealing the dynamics of effector secretion and function in interfering with host cellular processes, particularly signaling events, gene expression regulation, membrane trafficking, and autophagy. Furthermore, imaging-based screening approaches have demonstrated the mode of action of several bacterial effectors upon host cellular translocation. The rapid technological advancement of imaging technologies indicates that these techniques will continue to be at the center of numerous future breakthroughs delineating the dynamic processes of bacterial effector actions

Hierarchies of Host Factor Dynamics at the Entry Site of Shigella flexneri during Host Cell Invasion

International audienceShigella flexneri, the causative agent of bacillary dysentery, induces massive cytoskeletal rearrangement, resulting in its entry into nonphagocytic epithelial cells. The bacterium-engulfing membrane ruffles are formed by polymerizing actin, a process activated through injected bacterial effectors that target host small GTPases and tyrosine kinases. Once inside the host cell, S. flexneri escapes from the endocytic vacuole within minutes to move intra- and intercellularly. We quantified the fluorescence signals from fluorescently tagged host factors that are recruited to the site of pathogen entry and vacuolar escape. Quantitative time lapse fluorescence imaging revealed simultaneous recruitment of polymerizing actin, small GTPases of the Rho family, and tyrosine kinases. In contrast, we found that actin surrounding the vacuole containing bacteria dispersed first from the disassembling membranes, whereas other host factors remained colocalized with the membrane remnants. Furthermore, we found that the disassembly of the membrane remnants took place rapidly, within minutes after bacterial release into the cytoplasm. Superresolution visualization of galectin 3 through photoactivated localization microscopy characterized these remnants as small, specular, patchy structures between 30 and 300 nm in diameter. Using our experimental setup to track the time course of infection, we identified the S. flexneri effector IpgB1 as an accelerator of the infection pace, specifically targeting the entry step, but not vacuolar progression or escape. Together, our studies show that bacterial entry into host cells follows precise kinetics and that this time course can be targeted by the pathogen