Spotlight
Minireview
MinireviewThe Potential Role of Schistosome-Associated Factors as Therapeutic Modulators of the Immune SystemThe parasites and eggs of helminths, including schistosomes, are associated with factors that can modulate the nature and outcomes of host immune responses, particularly enhancing type 2 immunity and impairing the effects of type 1 and type 17 immunity. The main species of schistosomes that cause infection in humans are capable of generating a microenvironment that allows survival of the parasite by evasion of the immune response....
Molecular Pathogenesis
Molecular PathogenesisGenomic Profiling Reveals Distinct Routes To Complement Resistance in Klebsiella pneumoniaeThe serum complement system is a first line of defense against bacterial invaders. Resistance to killing by serum enhances the capacity of Klebsiella pneumoniae to cause infection, but it is an incompletely understood virulence trait. Identifying and characterizing the factors responsible for preventing activation of, and killing by, serum complement could inform new...
Molecular PathogenesisStaphylococcus aureus Fatty Acid Kinase FakA Modulates Pathogenesis during Skin Infection via ProteasesStaphylococcus aureus fatty acid kinase FakA is necessary for the incorporation of exogenous fatty acids into the lipid membrane. We previously demonstrated that the inactivation of fakA leads to decreased α-hemolysin (Hla) production but increased expression of the proteases SspAB and aureolysin in vitro, and that the ΔfakA mutant causes...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsInnate Effector Systems in Primary Human Macrophages Sensitize Multidrug-Resistant Klebsiella pneumoniae to AntibioticsInfections caused by multidrug-resistant (MDR) Klebsiella pneumoniae are difficult to treat with conventional antibiotics. Thus, alternative strategies to control the growth of MDR Klebsiella are warranted. We hypothesized that activation of innate effector systems could sensitize MDR K. pneumoniae to conventional antibiotics. Thus, human primary...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions | SpotlightLegionella pneumophila Excludes Autophagy Adaptors from the Ubiquitin-Labeled Vacuole in Which It ResidesXenophagy targets intracellular pathogens for destruction by the host autophagy pathway. Ubiquitin chains are conjugated to xenophagic targets and recruit multiple autophagy adaptors. The intracellular pathogen Legionella pneumophila resides in a vacuole that is ubiquitinated; however, this pathogen avoids xenophagic detection. Here, the mechanisms by which...
Bacterial Infections
Bacterial InfectionsGroup A Streptococcus AdcR Regulon Participates in Bacterial Defense against Host-Mediated Zinc Sequestration and Contributes to VirulenceColonization by pathogenic bacteria depends on their ability to overcome host nutritional defenses and acquire nutrients. The human pathogen group A streptococcus (GAS) encounters the host defense factor calprotectin (CP) during infection. CP inhibits GAS growth in vitro by imposing zinc (Zn) limitation. However, GAS counterstrategies to combat CP-mediated Zn limitation and the in vivo relevance of CP-GAS interactions...
Bacterial InfectionsThe uroS and yifB Genes Conserved among Tetrapyrrole Synthesizing-Deficient Bacteroidales Are Involved in Bacteroides fragilis Heme Assimilation and Survival in Experimental Intra-abdominal Infection and Intestinal ColonizationThe human intestinal anaerobic commensal and opportunistic pathogen Bacteroides fragilis does not synthesize the tetrapyrrole protoporphyrin IX in order to form heme that is required for growth stimulation and survival in vivo. Consequently, B. fragilis acquires essential heme from host...
Bacterial Infections | SpotlightThe Serratia marcescens Siderophore Serratiochelin Is Necessary for Full Virulence during Bloodstream InfectionSerratia marcescens is a bacterium frequently found in the environment, but over the last several decades it has evolved into a concerning clinical pathogen, causing fatal bacteremia. To establish such infections, pathogens require specific nutrients; one very limited but essential nutrient is iron. We sought to characterize the iron acquisition systems in...
Host Response and Inflammation
Host Response and Inflammationmcr-1 Gene Expression Modulates the Inflammatory Response of Human Macrophages to Escherichia coliMCR-1 is a plasmid-encoded phosphoethanolamine transferase able to modify the lipid A structure. It confers resistance to colistin and was isolated from human, animal, and environmental strains of Enterobacteriaceae, raising serious global health concerns. In this paper, we used recombinant mcr-1-expressing Escherichia coli to study the impact of MCR...
Host Response and InflammationMycobacterium abscessus Clearance by Neutrophils Is Independent of AutophagyMycobacterium abscessus, a rapidly growing nontuberculous mycobacterium, is increasingly prevalent in chronic lung disease, including cystic fibrosis, and infections are characterized by neutrophil-dominated environments. However, mechanisms of immune control are poorly understood. Azithromycin, a macrolide antibiotic with immunomodulatory effects, is used to treat...
Host Response and Inflammation | SpotlightSalmonella Persistence and Host Immunity Are Dictated by the Anatomical MicroenvironmentThe intracellular bacterial pathogen Salmonella is able to evade the immune system and persist within the host. In some cases, these persistent infections are asymptomatic for long periods and represent a significant public health hazard because the hosts are potential chronic carriers, yet the mechanisms that control persistence are incompletely understood. Using a...
Host Response and InflammationCirculating Cytokines Associated with Poor Pregnancy Outcomes in Beninese Exposed to Infection with Plasmodium falciparumMalaria during pregnancy is a major cause of maternal morbidity as well as fetal and neonatal mortality. Previous studies, including our own, suggested that placental and peripheral cytokine and chemokine levels measured at delivery can be used as biomarkers for pregnancy outcomes. However, the timing of malaria infection during pregnancy matters, and these studies do not address the effect of different cytokines in peripheral blood...
Host Response and InflammationNHR-49 Transcription Factor Regulates Immunometabolic Response and Survival of Caenorhabditis elegans during Enterococcus faecalis InfectionImmune response to pathogens is energetically expensive to the host; however, the cellular source of energy to fuel immune response remains unknown. In this study, we show that Caenorhabditis elegans exposed to pathogenic Gram-positive and Gram-negative bacteria or yeast rapidly utilizes lipid droplets, the major energy reserve. The nematode’s response to the...
Host Response and InflammationChlamydia Lipooligosaccharide Has Varied Direct and Indirect Roles in Evading both Innate and Adaptive Host Immune ResponsesChlamydia bacteria are obligate intracellular pathogens which can cause a variety of disease in humans and other vertebrate animals. To successfully complete its life cycle, Chlamydia must evade both intracellular innate immune responses and adaptive cytotoxic T cell responses. Here, we report on the role of the chlamydial lipooligosaccharide (LOS) in evading the immune response. Chlamydia infection is known...
Fungal and Parasitic Infections
Fungal and Parasitic Infections | SpotlightCryptococcus neoformans Evades Pulmonary Immunity by Modulating Xylose Precursor TransportCryptococcus neoformans is a fungal pathogen that kills almost 200,000 people each year and is distinguished by abundant and unique surface glycan structures that are rich in xylose. A mutant strain of C. neoformans that cannot transport xylose precursors into the secretory compartment is severely...
Fungal and Parasitic InfectionsMorphological and Motility Features of the Stable Bleb-Driven Monopodial Form of Entamoeba and Its Importance in EncystationEntamoeba histolytica and its reptilian counterpart and encystation model Entamoeba invadens formed a polarized monopodial morphology when treated with pentoxifylline. This morphology was propelled by retrograde flow of the cell surface resulting from a cyclic sol-gel conversion of cytoplasm and a...
Microbial Immunity and Vaccines
Microbial Immunity and VaccinesProgress towards the Development of a NEAT Vaccine for Anthrax II: Immunogen Specificity and Alum Effectiveness in an Inhalational ModelBacillus anthracis is the causative agent of anthrax disease, presents with high mortality, and has been at the center of bioweapon efforts. The only currently U.S. FDA-approved vaccine to prevent anthrax in humans is anthrax vaccine adsorbed (AVA), which is protective in several animal models and induces neutralizing antibodies against protective antigen (PA), the...
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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.