Spotlight
Molecular Pathogenesis
Molecular Pathogenesis | SpotlightMroQ Is a Novel Abi-Domain Protein That Influences Virulence Gene Expression in Staphylococcus aureus via Modulation of Agr Activity...Numerous factors have, to date, been identified as playing a role in the regulation of Agr activity in Staphylococcus aureus, including transcription factors, antisense RNAs, and host elements. Herein we investigated the product of SAUSA300_1984 (termed MroQ), a transmembrane Abi-domain/M79 protease-family protein, as a novel effector of this system.
Molecular Pathogenesis | SpotlightControl of Staphylococcus aureus Quorum Sensing by a Membrane-Embedded Peptidase...Gram-positive bacteria process and release small peptides, or pheromones, that act as signals for the induction of adaptive traits, including those involved in pathogenesis. One class of small signaling pheromones is the cyclic autoinducing peptides (AIPs), which regulate expression of genes that orchestrate virulence and persistence in a range of microbes, including staphylococci, listeriae, clostridia, and enterococci.
Molecular PathogenesisAnalysis of Invasive Nontypeable Haemophilus influenzae Isolates Reveals Selection for the Expression State of Particular Phase-Variable Lipooligosaccharide Biosynthetic GenesNontypeable Haemophilus influenzae (NTHi) is a major human pathogen, responsible for several acute and chronic infections of the respiratory tract. The incidence of invasive infections caused by NTHi is increasing worldwide.
Molecular PathogenesisArcanobacterium haemolyticum Utilizes Both Phospholipase D and Arcanolysin To Mediate Its Uptake into Nonphagocytic CellsArcanobacterium haemolyticum is an emerging human pathogen that causes pharyngitis and wound infections. A few studies have suggested that A. haemolyticum is able to induce its uptake into nonphagocytic epithelial cells, but the bacterial factors associated with host cell invasion and the host cell...
Molecular PathogenesisLoss of Trefoil Factor 2 Sensitizes Rat Pups to Systemic Infection with the Neonatal Pathogen Escherichia coli K1Gastrointestinal (GI) colonization of 2-day-old (P2) rat pups with Escherichia coli K1 results in translocation of the colonizing bacteria across the small intestine, bacteremia, and invasion of the meninges, with animals frequently succumbing to lethal infection. Infection, but not colonization, is strongly age dependent; pups become progressively less susceptible to...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCharacterization of Early Stages of Human Alveolar Infection by the Q Fever Agent Coxiella burnetiiHuman Q fever is caused by the intracellular bacterial pathogen Coxiella burnetii. Q fever presents with acute flu-like and pulmonary symptoms or can progress to chronic, severe endocarditis.
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsLeishmania donovani Lipophosphoglycan Increases Macrophage-Dependent Chemotaxis of CXCR6-Expressing Cells via CXCL16 InductionCXCL16 is a multifunctional chemokine that is highly expressed by macrophages and other immune cells in response to bacterial and viral pathogens; however, little is known regarding the role of CXCL16 during parasitic infections. The protozoan parasite Leishmania donovani is the causative agent of visceral leishmaniasis.
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCooperative Interactions between Trichomonas vaginalis and Associated Bacteria Enhance Paracellular Permeability of the Cervicovaginal Epithelium by Dysregulating Tight JunctionsThe human protozoan Trichomonas vaginalis is the causative agent of trichomoniasis, a prevalent sexually transmitted infection, which is accompanied by a species-diversified vaginal microbiota named community state type IV (CST-IV). Coincidently, CST-IV includes species associated with bacterial vaginosis (e.g.
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsDual Gene Expression Analysis Identifies Factors Associated with Staphylococcus aureus Virulence in Diabetic MiceStaphylococcus aureus is a major human pathogen of the skin. The global burden of diabetes is high, with S. aureus being a major complication of diabetic wound infections.
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsThe Plasmid-Encoded pGP3 Promotes Chlamydia Evasion of Acidic Barriers in Both Stomach and VaginaAlthough Chlamydia trachomatis is a human genital tract pathogen, chlamydial organisms have frequently been detected in both vaginal and rectal swab samples of animals and humans. The plasmid-encoded pGP3, a genital tract virulence factor, is essential for Chlamydia muridarum to colonize the mouse...
Bacterial Infections
Bacterial InfectionsAlternative Enzyme Protection Assay To Overcome the Drawbacks of the Gentamicin Protection Assay for Measuring Entry and Intracellular Survival of StaphylococciPrecise enumeration of living intracellular bacteria is the key step to estimate the invasion potential of pathogens and host immune responses to understand the mechanism and kinetics of bacterial pathogenesis. Therefore, quantitative assessment of host-pathogen interactions is essential for development of novel antibacterial therapeutics for infectious disease.
Bacterial Infections | SpotlightBorrelia burgdorferi bbk13 Is Critical for Spirochete Population Expansion in the Skin during Early InfectionLyme disease is caused by the spirochete Borrelia burgdorferi and is transmitted via the bite of an infected tick. B. burgdorferi enters the skin, disseminates via the bloodstream, and infects various distal tissues, leading to inflammatory sequelae, such as Lyme arthritis and Lyme carditis.
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Host Response and Inflammation
Host Response and InflammationDietary Chitin Particles Called Mimetic Fungi Ameliorate Colitis in Toll-Like Receptor 2/CD14- and Sex-Dependent MannersChitin is a natural N-acetylglucosamine polymer and a major structural component of fungal cell walls. Dietary chitin is mucoadhesive; anti-inflammatory effects of chitin microparticles (CMPs; 1- to 10-μm diameters) have been demonstrated in models of inflammatory bowel disease (IBD).
Host Response and Inflammation | SpotlightTranscriptional Analysis Shows a Robust Host Response to Toxoplasma gondii during Early and Late Chronic Infection in Both Male and Female MiceThe long-term host effects caused by the protozoan parasite Toxoplasma gondii are poorly understood. High-throughput RNA sequencing analysis previously determined that the host response in the brain was greater and more complex at 28 days than at 10 days postinfection.
Host Response and Inflammation | SpotlightA Phenome-Wide Association Study Uncovers a Pathological Role of Coagulation Factor X during Acinetobacter baumannii InfectionCoagulation and inflammation are interconnected, suggesting that coagulation plays a key role in the inflammatory response to pathogens. A phenome-wide association study (PheWAS) was used to identify clinical phenotypes of patients with a polymorphism in coagulation factor X.
Host Response and InflammationInterferon Lambda Inhibits Bacterial Uptake during Influenza SuperinfectionInfluenza kills 30,000 to 40,000 people each year in the United States and causes 10 times as many hospitalizations. A common complication of influenza is bacterial superinfection, which exacerbates morbidity and mortality from the viral illness.
Host Response and InflammationNeutrophils Dampen Adaptive Immunity in BrucellosisBrucella organisms are intracellular stealth pathogens of animals and humans. The bacteria overcome the assault of innate immunity at early stages of an infection.
Host Response and InflammationYersinia pestis Pla Protein Thwarts T Cell Defense against PlaguePlague is a rapidly lethal human disease caused by the bacterium Yersinia pestis. This study demonstrated that the Y. pestis plasminogen activator Pla, a protease that promotes fibrin degradation, thwarts T cell-mediated defense against fully virulent...
Host Response and InflammationInterleukin-10 Produced by Myeloid-Derived Suppressor Cells Provides Protection to Carbapenem-Resistant Klebsiella pneumoniae Sequence Type 258 by Enhancing Its Clearance in the AirwaysCarbapenem-resistant Klebsiella pneumoniae sequence type 258 (CRKP-ST258) can cause chronic infections in lungs and airways, with repeated episodes of bacteremia. In this report we addressed whether the recruitment of myeloid cells producing the anti-inflammatory cytokine interleukin-10 (IL-10) modulates the clearance of CKRP-ST258 in the lungs and establishes...
Host Response and InflammationDifferential Recognition of Vibrio parahaemolyticus OmpU by Toll-Like Receptors in Monocytes and Macrophages for the Induction of Proinflammatory ResponsesVibrio parahaemolyticus is a human pathogen, and it is a major cause of severe gastroenteritis in coastal areas. OmpU is one of the major outer membrane porins of V. parahaemolyticus.
Fungal and Parasitic Infections
Fungal and Parasitic InfectionsMetabolites Involved in Immune Evasion by Batrachochytrium dendrobatidis Include the Polyamine SpermidineAmphibians have been declining around the world for more than four decades. One recognized driver of these declines is the chytrid fungus Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis.
Fungal and Parasitic Infections | SpotlightThe Mouse Inhalation Model of Cryptococcus neoformans Infection Recapitulates Strain Virulence in Humans and Shows that Closely Related Strains Can Possess Differential VirulenceCryptococcal meningitis (CM) causes high rates of HIV-related mortality, yet the Cryptococcus factors influencing patient outcome are not well understood. Pathogen-specific traits, such as the strain genotype and degree of antigen shedding, are associated with the clinical outcome, but the underlying biology remains elusive.
Fungal and Parasitic InfectionsCryptosporidium parvum Subtilisin-Like Serine Protease (SUB1) Is Crucial for Parasite Egress from Host CellsDespite the severity and global burden of Cryptosporidium infection, treatments are less than optimal, and there is no effective vaccine. Egress from host cells is a key process for the completion of the life cycle of apicomplexan parasites.
Host-Associated Microbial Communities
Host-Associated Microbial Communities | SpotlightSortase-Dependent Proteins Promote Gastrointestinal Colonization by EnterococciThe human gastrointestinal tract (GIT) is inhabited by a dense microbial community of symbionts. Enterococci are among the earliest members of this community and remain core members of the GIT microbiota throughout life.
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Infection and Immunity® (IAI) reports key discoveries that help microbiologists, immunologists, epidemiologists, pathologists, and clinicians to gain new insights into the underlying mechanisms of host-pathogen interactions and develop novel strategies to prevent or treat infectious diseases.