Antimicrobial resistance transmission in antibiotic-free poultry production pyramid

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Longitudinal study reveals persistence of multidrug resistant Escherichia coli and horizontal transfer of antimicrobial resistance genes in the antibiotic free poultry production pyramid

International audienceAntimicrobial resistance (AMR) has decreased in French broiler production for the last 10 years, linked to lower antibiotics use. Nonetheless, animal gut and the breeding environment are still considered as reservoirs of AMR bacteria. The aim of this study was to characterize the AMR dynamic of transmission and persistence in an experimental facility simulating the broiler production pyramid (WPC eposter 380). Multiresistant E. coli isolated from feces (n=121) of chickens from five families followed over three generations including two sibling batches, one for reproduction and one for meat production, and from each of the two breeding environment samples (n=31) were subjected to whole genome sequencing (Illumina technology). A subset of isolates (n=36) were also sequenced using Oxford Nanopore MinION technology. The 152 E. coli isolates mainly belonged to the phylogroup A (55.9 %) and to the phylogroup B1 (36.2%). A very strong association was observed between phylogroups and batches, with most phylogroup A isolates (96.5 %) coming from the reproduction batch, and most phylogroup B1 isolates (90.9 %) coming from the meat production batch. The major sequence types ST2701 (A), ST93 (A), ST162 (B1), and ST 453 (B1) were shared between families and persisted through generations, and in the environment. The detected AMR genes in E. coli isolates showed a weak diversity, with several genes (i.e. strA, aadA, sul, dfrA, tet(A), blaTEM1) being shared by diverse ST and even phylogroups. However, MinION-based analysis showed that they were carried by independent plasmids, i.e. pIncFIB and pIncHI1 in ST2701, pIncBOKZ in ST93, pIncI1 in ST453. Exchange of AMR genes between ST was nonetheless observed at the level of mobile genetic elements (Insertion Sequences, integrons, transposons). Our results indicate that the persistence of specific ST in the breeding environment contributes to the transmission of AMR to animals of the successive batches without direct vertical transmission (mother to offspring) between generations. Rearrangements observed in the genetic environment of AMR genes also indicate occasional horizontal transfers within the breeding facility

Persistence of multidrug resistant Escherichia coli in chicken breeding environment

book of abstracts, pas d'ISBNInternational audienceAntimicrobial resistance (AMR) has decreased in French broiler production for the last 10 years, linked to lower antibiotics use. Nonetheless, animal gut and the breeding environment are still considered as reservoirs of resistant zoonotic bacteria. The aim of this study was to characterize the dynamic of AMR transmission and persistence in an experimental facility simulating a broiler production system with no antibiotic exposition. Chickens from five families were followed over three generations and two breeding environments (meat production and lineage reproduction), and commensal AMR E. coli strains were isolated from feces at different weeks of age, as well as from building surfaces before flock entry. Among the ca. 600 non-redundant isolates collected, a subset of 128 multidrug resistant isolates (at least 4 antibiotic classes) were subjected to sequencing with lllumina and/or Oxford Nanopore technologies. The vast majority of isolates (91%) belonged to six unrelated sequence types from phylogroups A (ST206, ST2701, ST93) and B1 (ST162, ST1611 and ST453), none being reported as major causes of human or animal infection. These ST were shared between chicken families, generations and sample type (feces or surfaces), but segregated by breeding environment: isolates of phylogroup A were associated with reproductive animals while isolates of phylogroup B1 were associated with production animals. The AMR gene repertoire of sequenced isolates showed a weak diversity, withseveral genes (i.e. tet(A), blaTEM-1, sul2, dfrA1, aadA1) being shared by most ST. However, they were carried by independent plasmids, i.e. pIncF and pIncHI1 in ST2701 isolates, pIncZ in ST93 isolates, or pIncI1 in ST453 isolates. Our results indicate that the transmission of AMR in animals of successive generations is mainly driven by the persistence of specific clones in our environment facility, rather than direct vertical transmission (from mother to offspring) or horizontal transmission of resistance plasmids

Persistence of multidrug resistant Escherichia coli in poultry

International audienceAntimicrobial resistance (AMR) has decreased in French broiler production for the last 10 years, linked to lower antibiotics use. Nonetheless, animal gut and the breeding environment are still considered as reservoirs of resistant zoonotic bacteria. The aim of this study was to characterize the dynamic of AMR transmission and persistence in an experimental facility simulating a broiler production system with no antibiotic exposition.Chickens from five families were followed over three generations and two breeding environments (meat production and lineage reproduction), and commensal E. coli strains were isolated from feces at different weeks of age, as well as from building surfaces before flock entry. Among the ca. 600 non-redundant isolates collected, a subset of 128 multidrug resistant isolates (at least 4 antibiotic classes) were subjected to sequencing with lllumina and/or Oxford Nanopore technologies. The vast majority of isolates (91%) belonged to six unrelated sequence types from phylogroups A (ST206, ST2701, ST93) and B1 (ST162, ST1611 and ST453), none being reported as major causes of human or animal infection. These ST were shared between chicken families, generations and sample type (feces or surfaces), but segregated by breeding environment: isolates of phylogroup A were associated with reproductive animals while isolates of phylogroup B1 were associated with production animals. The AMR gene repertoire of sequenced isolates showed a weak diversity, with several genes (i.e. tet(A), blaTEM-1, sul2, dfrA1, aadA1) being shared by most ST. However, they were carried by independent plasmids, i.e. pIncF and pIncHI1 in ST2701 isolates, pIncZ in ST93 isolates, or pIncI1 in ST453 isolates. Our results indicate that the transmission of AMR in animals of successive generations is mainly driven by the persistence of specific clones in the breeding environment, rather than direct vertical transmission (from mother to offspring) or horizontal transmission of resistance plasmids

Real-Time Monitoring of Exosome Enveloped-AAV Spreading by Endomicroscopy Approach: A New Tool for Gene Delivery in the Brain

International audienceExosomes represent a strategy for optimizing the adeno-associated virus (AAV) toward the development of novel therapeutic options for neurodegenerative disorders. However, in vivo spreading of exosomes and AAVs after intracerebral administration is poorly understood. This study provides an assessment and comparison of the spreading into the brain of exosome-enveloped AAVs (exo-AAVs) or unassociated AAVs (std-AAVs) through in vivo optical imaging techniques like probe-based confocal laser endomicroscopy (pCLE) and ex vivo fluorescence microscopy. The std-AAV serotypes (AAV6 and AAV9) encoding the GFP were enveloped in exosomes and injected into the ipsilateral hippocampus. At 3 months post-injection, pCLE detected enhanced GFP expression of both exo-AAV serotypes in contralateral hemispheres compared to std-AAVs. Although sparse GFP-positive astro-cytes were observed using exo-AAVs, our results show that the enhancement of the transgene expression resulting from exo-AAVs was largely restricted to neurons and oligodendro-cytes. Our results suggest (1) the possibility of combining gene therapy with an endoscopic approach to enable tracking of exo-AAV spread, and (2) exo-AAVs allow for widespread, long-term gene expression in the CNS, supporting the use of exo-AAVs as an efficient gene delivery tool

Inhibition of DYRK1A proteolysis modifies its kinase specificity and rescues Alzheimer phenotype in APP/PS1 mice

Abstract Recent evidences suggest the involvement of DYRK1A (dual specificity tyrosine phosphorylation-regulated kinase 1 A) in Alzheimer’s disease (AD). Here we showed that DYRK1A undergoes a proteolytic processing in AD patients hippocampus without consequences on its kinase activity. Resulting truncated forms accumulate in astrocytes and exhibit increased affinity towards STAT3ɑ, a regulator of inflammatory process. These findings were confirmed in APP/PS1 mice, an amyloid model of AD, suggesting that this DYRK1A cleavage is a consequence of the amyloid pathology. We identified in vitro the Leucettine L41 as a compound able to prevent DYRK1A proteolysis in both human and mouse protein extracts. We then showed that intraperitoneal injections of L41 in aged APP/PS1 mice inhibit STAT3ɑ phosphorylation and reduce pro-inflammatory cytokines levels (IL1- β, TNF-ɑ and IL-12) associated to an increased microglial recruitment around amyloid plaques and decreased amyloid-β plaque burden. Importantly, L41 treatment improved synaptic plasticity and rescued memory functions in APP/PS1 mice. Collectively, our results suggest that DYRK1A may contribute to AD pathology through its proteolytic process, reducing its kinase specificity. Further evaluation of inhibitors of DYRK1A truncation promises a new therapeutic approach for AD