Antimicrobial Resistance Profiling and Molecular Epidemiological Analysis of Extended Spectrum β-Lactamases Produced by Extraintestinal Invasive Isolates From Ethiopia: The Presence of International High-Risk Clones ST131 and ST410 Revealed.

The treatment of invasive infections is a challenge because of the emergence and rapid spread of multidrug resistant strains. Particular problems are those strains that produce extended spectrum β-lactamases (ESBL's). Although the global characterization of these enzymes is advanced, knowledge of their molecular basis among clinical isolates in Ethiopia is extremely limited.

RNA atlas of human bacterial pathogens uncovers stress dynamics linked to infection.

Bacterial processes necessary for adaption to stressful host environments are potential targets for new antimicrobials. Here, we report large-scale transcriptomic analyses of 32 human bacterial pathogens grown under 11 stress conditions mimicking human host environments. The potential relevance of the in vitro stress conditions and responses is supported by comparisons with available in vivo transcriptomes of clinically important pathogens.

Spatiotemporal Variations in Growth Rate and Virulence Plasmid Copy Number during Infection.

Pathogenic spp. depend on the activity of a potent virulence plasmid-encoded / type 3 secretion system (T3SS) to colonize hosts and cause disease. It was recently shown that upregulates the virulence plasmid copy number (PCN) during infection and that the resulting elevated gene dose of plasmid-encoded T3SS genes is essential for virulence.

ProkSeq for complete analysis of RNA-Seq data from prokaryotes.

Summary: Since its introduction, RNA-Seq technology has been used extensively in studies of pathogenic bacteria to identify and quantify differences in gene expression across multiple samples from bacteria exposed to different conditions. With some exceptions, tools for studying gene expression, determination of differential gene expression, downstream pathway analysis and normalization of data collected in extreme biological conditions is still lacking. Here, we describe ProkSeq, a user-friendly, fully automated RNA-Seq data analysis pipeline designed for prokaryotes.

Targeted inhibition of ERα signaling and PIP5K1α/Akt pathways in castration-resistant prostate cancer.

Selective ERα modulator, tamoxifen, is well tolerated in a heavily pretreated castration-resistant prostate cancer (PCa) patient cohort. However, its targeted gene network and whether expression of intratumor ERα due to androgen deprivation therapy (ADT) may play a role in PCa progression is unknown. In this study, we examined the inhibitory effect of tamoxifen on castration-resistant PCa in vitro and in vivo.

Genome-Scale Mapping Reveals Complex Regulatory Activities of RpoN in Yersinia pseudotuberculosis.

RpoN, an alternative sigma factor commonly known as σ, is implicated in persistent stages of infections in which genes associated with this regulator are upregulated. We here combined phenotypic and genomic assays to provide insight into its role and function in this pathogen. RpoN was found essential for virulence in mice, and functional assays showed that it controls biofilm formation and motility.

Accumulation of virulence-associated proteins in Campylobacter jejuni Outer Membrane Vesicles at human body temperature.

Campylobacter jejuni is the major cause of bacterial gastroenteritis in humans. In contrast, colonization in avian hosts is asymptomatic. Body temperature differs between human (37 °C) and avian (42 °C) hosts, and bacterial growth in 37 °C is therefore a potential cue for higher virulence properties during human infection.

Campylobacter jejuni bile exposure influences outer membrane vesicles protein content and bacterial interaction with epithelial cells.

Campylobacter jejuni is a prevalent human pathogen and a major cause of bacterial gastroenteritis in the world. In humans, C. jejuni colonizes the intestinal tract and its tolerance to bile is crucial for bacteria to survive and establish infection.

The Amino-Terminal Part of the Needle-Tip Translocator LcrV of Is Required for Early Targeting of YopH and Virulence.

Type III secretion systems (T3SS) are dedicated to targeting anti-host effector proteins into the cytosol of the host cell to promote bacterial infection. Delivery of the effectors requires three specific translocator proteins, of which the hydrophilic translocator, LcrV, is located at the tip of the T3SS needle and is believed to facilitate insertion of the two hydrophobic translocators into the host cell membrane. Here we used as a model to study the role of LcrV in T3SS mediated intracellular effector targeting.

Yersinia pseudotuberculosis Blocks Neutrophil Degranulation.

Neutrophils are essential components of immunity and are rapidly recruited to infected or injured tissue. Upon their activation, neutrophils release granules to the cell's exterior, through a process called degranulation. These granules contain proteins with antimicrobial properties that help combat infection.

Loss of the DNA Damage Repair Kinase ATM Impairs Inflammasome-Dependent Anti-Bacterial Innate Immunity.

The ATM kinase is a central component of the DNA damage repair machinery and redox balance. ATM dysfunction results in the multisystem disease ataxia-telangiectasia (AT). A major cause of mortality in AT is respiratory bacterial infections.

Increased plasmid copy number is essential for Yersinia T3SS function and virulence.

Pathogenic bacteria have evolved numerous virulence mechanisms that are essential for establishing infections. The enterobacterium Yersinia uses a type III secretion system (T3SS) encoded by a 70-kilobase, low-copy, IncFII-class virulence plasmid. We report a novel virulence strategy in Y.

Pathogenic Yersinia Promotes Its Survival by Creating an Acidic Fluid-Accessible Compartment on the Macrophage Surface.

Microbial pathogens and host immune cells each initiate events following their interaction in an attempt to drive the outcome to their respective advantage. Here we show that the bacterial pathogen Yersinia pseudotuberculosis sustains itself on the surface of a macrophage by forming acidic fluid-accessible compartments that are partially bounded by the host cell plasma membrane. These Yersinia-containing acidic compartments (YACs) are bereft of the early endosomal marker EEA1 and the lysosomal antigen LAMP1 and readily form on primary macrophages as well as macrophage-like cell lines.

Reprogramming of Yersinia from virulent to persistent mode revealed by complex in vivo RNA-seq analysis.

We recently found that Yersinia pseudotuberculosis can be used as a model of persistent bacterial infections. We performed in vivo RNA-seq of bacteria in small cecal tissue biopsies at early and persistent stages of infection to determine strategies associated with persistence. Comprehensive analysis of mixed RNA populations from infected tissues revealed that Y.

Colonization of cecum is important for development of persistent infection by Yersinia pseudotuberculosis.

Yersiniosis is a human disease caused by the bacterium Yersinia pseudotuberculosis or Yersinia enterocolitica. The infection is usually resolved but can lead to postinfectious sequelae, including reactive arthritis and erythema nodosum. The commonly used Yersinia mouse infection model mimics acute infection in humans to some extent but leads to systemic infection and eventual death.

Bacteria induce prolonged PMN survival via a phosphatidylcholine-specific phospholipase C- and protein kinase C-dependent mechanism.

Polymorphonuclear leukocytes (PMNs) are essential for the human innate immune defense, limiting expansion of invading microorganisms. PMN turnover is controlled by apoptosis, but the regulating signaling pathways remain elusive, largely due to inherent differences between mice and humans that undermine use of mouse models for understanding human PMN biology. Here, we aim to elucidate signal transduction mediating survival of human peripheral blood PMNs in response to bacteria, such as Yersinia pseudotuberculosis, an enteropathogen that causes the gastro-intestinal disease yersiniosis, as well as Escherichia coli and Staphylococcus aureus.

Yersinia pseudotuberculosis efficiently escapes polymorphonuclear neutrophils during early infection.

The human-pathogenic species of the Gram-negative genus Yersinia preferentially target and inactivate cells of the innate immune defense, suggesting that this is a critical step by which these bacteria avoid elimination and cause disease. In this study, bacterial interactions with dendritic cells, macrophages, and polymorphonuclear neutrophils (PMNs) in intestinal lymphoid tissues during early Yersinia pseudotuberculosis infection were analyzed. Wild-type bacteria were shown to interact mainly with dendritic cells, but not with PMNs, on day 1 postinfection, while avirulent yopH and yopE mutants interacted with PMNs as well as with dendritic cells.

Metabolic profiling for detection of Staphylococcus aureus infection and antibiotic resistance.

Due to slow diagnostics, physicians must optimize antibiotic therapies based on clinical evaluation of patients without specific information on causative bacteria. We have investigated metabolomic analysis of blood for the detection of acute bacterial infection and early differentiation between ineffective and effective antibiotic treatment. A vital and timely therapeutic difficulty was thereby addressed: the ability to rapidly detect treatment failures because of antibiotic-resistant bacteria.

Type III secretion translocon assemblies that attenuate Yersinia virulence.

Type III secretion enables bacteria to intoxicate eukaryotic cells with anti-host effectors. A class of secreted cargo are the two hydrophobic translocators that form a translocon pore in the host cell plasma membrane through which the translocated effectors may gain cellular entry. In pathogenic Yersinia, YopB and YopD shape this translocon pore.

Role of YopK in Yersinia pseudotuberculosis resistance against polymorphonuclear leukocyte defense.

The enteropathogen Yersinia pseudotuberculosis can survive in the harsh environment of lymphoid compartments that abounds in immune cells. This capacity is dependent on the plasmid-encoded Yersinia outer proteins (Yops) that are delivered into the host cell via a mechanism involving the Yersinia type III secretion system. We show that the virulence protein YopK has a role in the mechanism by which Y.

Coiled-coils in the YopD translocator family: a predicted structure unique to the YopD N-terminus contributes to full virulence of Yersinia pseudotuberculosis.

Pathogenic Yersinia all harbor a virulence plasmid-encoded Ysc-Yop T3SS. In this system, translocator function is performed by the hydrophobic proteins YopB and YopD. With the goal to better understand how YopD orchestrates yop-regulatory control, translocon pore formation and Yop effector translocation, we performed an in silico prediction of coiled-coil motifs in YopD and YopD-like sequences from other bacteria.

Immune response to diphtheria toxin-mediated depletion complicates the use of the CD11c-DTR(tg) model for studies of bacterial gastrointestinal infections.

Dendritic cells play an important role in the immune response against pathogens, as they are responsible for the activation and control of both innate and adaptive immune responses. The CD11c-DTR(tg) model, which allows transient elimination of dendritic cells by diphtheria toxin-treatment (DTx), has been extensively used to study the importance of this immune cell during steady-state and infection conditions in mice. Infecting dendritic cell-depleted mice orally with Yersinia pseudotuberculosis results in a markedly reduced level of infection compared with infection of non-depleted mice.