Chicken liver is a potential reservoir of bacteriophages and phage-derived particles containing antibiotic resistance genes

Poultry meat production is one of the most important agri-food industries in the world. The selective pressure exerted by widespread prophylactic or therapeutic use of antibiotics in intensive chicken farming favours the development of drug resistance in bacterial populations. Chicken liver, closely connected with the intestinal tract, has been directly involved in food-borne infections and found to be contaminated with pathogenic bacteria, including Campylobacter and Salmonella. In this study, 74 chicken livers, divided into sterile and non-sterile groups, were analysed, not only for microbial indicators but also for the presence of phages and phage particles containing antibiotic resistance genes (ARGs). Both bacteria and phages were detected in liver tissues, including those dissected under sterile conditions. The phages were able to infect Escherichia coli and showed a Siphovirus morphology. The chicken livers contained from 10 3 to 10 6 phage particles per g, which carried a range of ARGs (bla , bla , sul1, qnrA, armA and tetW) detected by qPCR. The presence of phages in chicken liver, mostly infecting E. coli, was confirmed by metagenomic analysis, although this technique was not sufficiently sensitive to identify ARGs. In addition, ARG-carrying phages were detected in chicken faeces by qPCR in a previous study of the group. Comparison of the viromes of faeces and liver showed a strong coincidence of species, which suggests that the phages found in the liver originate in faeces. These findings suggests that phages, like bacteria, can translocate from the gut to the liver, which may therefore constitute a potential reservoir of antibiotic resistance genes. Phage particles carrying antibiotic resistant genes have been found in chicken livers. Metagenomic analysis of chicken liver viromes (PL) and chicken faeces viromes (HP) suggests that these phage particles could translocate from chicken gut to the liver

First insights into the pleiotropic role of vrf (yedF), a newly characterized gene of Salmonella Typhimurium

Salmonella possesses virulence determinants that allow replication under extreme conditions and invasion of host cells, causing disease. Here, we examined four putative genes predicted to encode membrane proteins (ydiY, ybdJ, STM1441 and ynaJ) and a putative transcriptional factor (yedF). These genes were identified in a previous study of a S. Typhimurium clinical isolate and its multidrug-resistant counterpart. For STM1441 and yedF a reduced ability to interact with HeLa cells was observed in the knock-out mutants, but an increase in this ability was absent when these genes were overexpressed, except for yedF which phenotype was rescued when yedF was restored. In the absence of yedF, decreased expression was seen for: i) virulence-related genes involved in motility, chemotaxis, attachment and survival inside the host cell; ii) global regulators of the invasion process (hilA, hilC and hilD); and iii) factors involved in LPS biosynthesis. In contrast, an increased expression was observed for anaerobic metabolism genes. We propose yedF is involved in the regulation of Salmonella pathogenesis and contributes to the activation of the virulence machinery. Moreover, we propose that, when oxygen is available, yedF contributes sustained repression of the anaerobic pathway. Therefore, we recommend this gene be named vrf, for virulence-related factor

First insights into the pleiotropic role of vrf (yedF), a newly characterized gene of Salmonella Typhimurium

Salmonella possesses virulence determinants that allow replication under extreme conditions and invasion of host cells, causing disease. Here, we examined four putative genes predicted to encode membrane proteins (ydiY, ybdJ, STM1441 and ynaJ) and a putative transcriptional factor (yedF). These genes were identified in a previous study of a S. Typhimurium clinical isolate and its multidrug-resistant counterpart. For STM1441 and yedF a reduced ability to interact with HeLa cells was observed in the knock-out mutants, but an increase in this ability was absent when these genes were overexpressed, except for yedF which phenotype was rescued when yedF was restored. In the absence of yedF, decreased expression was seen for: i) virulence-related genes involved in motility, chemotaxis, attachment and survival inside the host cell; ii) global regulators of the invasion process (hilA, hilC and hilD); and iii) factors involved in LPS biosynthesis. In contrast, an increased expression was observed for anaerobic metabolism genes. We propose yedF is involved in the regulation of Salmonella pathogenesis and contributes to the activation of the virulence machinery. Moreover, we propose that, when oxygen is available, yedF contributes sustained repression of the anaerobic pathway. Therefore, we recommend this gene be named vrf, for virulence-related factor

First insights into the pleiotropic role of vrf (yedF), a newly characterized gene of Salmonella Typhimurium

Salmonella possesses virulence determinants that allow replication under extreme conditions and invasion of host cells, causing disease. Here, we examined four putative genes predicted to encode membrane proteins (ydiY, ybdJ, STM1441 and ynaJ) and a putative transcriptional factor (yedF). These genes were identified in a previous study of a S. Typhimurium clinical isolate and its multidrug-resistant counterpart. For STM1441 and yedF a reduced ability to interact with HeLa cells was observed in the knock-out mutants, but an increase in this ability was absent when these genes were overexpressed, except for yedF which phenotype was rescued when yedF was restored. In the absence of yedF, decreased expression was seen for: i) virulence-related genes involved in motility, chemotaxis, attachment and survival inside the host cell; ii) global regulators of the invasion process (hilA, hilC and hilD); and iii) factors involved in LPS biosynthesis. In contrast, an increased expression was observed for anaerobic metabolism genes. We propose yedF is involved in the regulation of Salmonella pathogenesis and contributes to the activation of the virulence machinery. Moreover, we propose that, when oxygen is available, yedF contributes sustained repression of the anaerobic pathway. Therefore, we recommend this gene be named vrf, for virulence-related factor

Characterization of Plasmodium vivax Proteins in Plasma-Derived Exosomes From Malaria-Infected Liver-Chimeric Humanized Mice

Exosomes are extracellular vesicles of endocytic origin containing molecular signatures implying the cell of origin; thus, they offer a unique opportunity to discover biomarkers of disease. Plasmodium vivax, responsible for more than half of all malaria cases outside Africa, is a major obstacle in the goal of malaria elimination due to the presence of dormant liver stages (hypnozoites), which after the initial infection may reactivate to cause disease. Hypnozoite infection is asymptomatic and there are currently no diagnostic tools to detect their presence. The human liver-chimeric (FRG huHep) mouse is a robust P. vivax infection model for exo-erythrocytic development of liver stages, including hypnozoites. We studied the proteome of plasma-derived exosomes isolated from P. vivax infected FRG huHep mice with the objective of identifying liver-stage expressed parasite proteins indicative of infection. Proteomic analysis of these exosomes showed the presence of 290 and 234 proteins from mouse and human origin, respectively, including canonical exosomal markers. Human proteins include proteins previously detected in liver-derived exosomes, highlighting the potential of this chimeric mouse model to study plasma exosomes derived unequivocally from human hepatocytes. Noticeably, we identified 17 parasite proteins including enzymes, surface proteins, components of the endocytic pathway and translation machinery, as well as uncharacterized proteins. Western blot analysis validated the presence of human arginase-I and an uncharacterized P. vivax protein in plasma-derived exosomes. This study represents a proof-of-principle that plasma-derived exosomes from P. vivax infected FRG-huHep mice contain human hepatocyte and P. vivax proteins with the potential to unveil biological features of liver infection and identify biomarkers of hypnozoite infection

Relative abundance of miRNA and small RNA clusters.

<p>(A, C) Plasma, (B, D) milk. The x-axis represents miRNAs (A, B) or small RNA clusters (C, D) ordered according to their expression level and the y-axis represents the abundance as percentage of reads (%) (average of all samples). Error bar shows SD.</p

Main characteristics of study participants.

<p>Main characteristics of study participants.</p

Number of clusters and abundance in milk and plasma.

<p>Number of clusters and abundance in milk and plasma.</p

Quality control and mapped reads to miRNAs [mean and (SD)], by biofluid.

<p>Quality control and mapped reads to miRNAs [mean and (SD)], by biofluid.</p

Differential levels of miRNAs by biofluid—top 10 ordered by p value.

<p>Differential levels of miRNAs by biofluid—top 10 ordered by p value.</p