Spotlight
Molecular Pathogenesis
Molecular PathogenesisPhoPR Contributes to Staphylococcus aureus Growth during Phosphate Starvation and Pathogenesis in an Environment-Specific MannerMicrobial pathogens must obtain all essential nutrients, including phosphate, from the host. To optimize phosphate acquisition in diverse and dynamic environments, such as mammalian tissues, many bacteria use the PhoPR two-component system.
Molecular PathogenesisNanR Regulates Sporulation and Enterotoxin Production by Clostridium perfringens Type F Strain F4969Clostridium perfringens type F strains, which produce C. perfringens enterotoxin (CPE), are a major cause of gastrointestinal infections, including the second most prevalent bacterial foodborne illness and 5 to 10% cases of antibiotic-associated diarrhea. Virulence of type F strains is primarily...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsDesialylation of Platelets by Pneumococcal Neuraminidase A Induces ADP-Dependent Platelet HyperreactivityPlatelets are increasingly recognized to play a role in the complications of Streptococcus pneumoniae infections. S. pneumoniae expresses neuraminidases, which may alter glycans on the platelet surface.
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsEspH Suppresses Erk by Spatial Segregation from CD81 Tetraspanin MicrodomainsEnteropathogenic Escherichia coli (EPEC) belongs to a group of enteric human pathogens known as attaching-and-effacing (A/E) pathogens, which utilize a type III secretion system (T3SS) to translocate a battery of effector proteins from their own cytoplasm into host intestinal epithelial cells. Here we identified EspH to be an effector that prompts the recruitment of...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsLipid A Remodeling Is a Pathoadaptive Mechanism That Impacts Lipopolysaccharide Recognition and Intracellular Survival of Burkholderia pseudomalleiBurkholderia pseudomallei causes the severe disease melioidosis. The bacterium subverts the host immune system and replicates inside cells, and host mortality results primarily from sepsis-related complications.
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCoxiella burnetii Blocks Intracellular Interleukin-17 Signaling in MacrophagesCoxiella burnetii is an obligate intracellular bacterium and the etiological agent of Q fever. Successful host cell infection requires the Coxiella type IVB secretion system (T4BSS), which translocates bacterial effector proteins across the vacuole membrane into the host cytoplasm, where they...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsRelative Roles of Listeriolysin O, InlA, and InlB in Listeria monocytogenes Uptake by Host CellsListeria monocytogenes is a facultative intracellular pathogen that infects a wide variety of cells, causing the life-threatening disease listeriosis. L. monocytogenes virulence factors include two surface invasins, InlA and InlB, known to promote bacterial uptake by host cells, and the secreted...
Bacterial Infections
Bacterial Infections | SpotlightSurvival of Staphylococcus epidermidis in Fibroblasts and OsteoblastsStaphylococcus epidermidis is a leading cause of infections associated with indwelling medical devices, including prosthetic joint infection. While biofilm formation is assumed to be the main mechanism underlying the chronic infections S. epidermidis causes, we hypothesized that...
Bacterial InfectionsThe Psoriasis Risk Allele HLA-C*06:02 Shows Evidence of Association with Chronic or Recurrent Streptococcal TonsillitisPharyngeal tonsillitis is one of the most common upper respiratory tract infections, and group A streptococcus is the most important bacterial pathogen causing it. While most patients experience tonsillitis only rarely, a subset of patients suffers from recurrent or chronic tonsillitis or pharyngitis.
Bacterial InfectionsViable Coxiella burnetii Induces Differential Cytokine Responses in Chronic Q Fever Patients Compared to Heat-Killed Coxiella burnetiiCytokine responses of chronic Q fever patients to the intracellular bacterium Coxiella burnetii have mostly been studied using ex vivo stimulation of immune cells with heat-killed C. burnetii due to the extensive measures needed to work with viable biosafety level 3 agents. Whether research...
Bacterial InfectionsSex Matters: Male Hamsters Are More Susceptible to Lethal Infection with Lower Doses of Pathogenic Leptospira than Female HamstersA somewhat contradictory published body of evidence suggests that sex impacts severity outcomes of human leptospirosis. In this study, we used an acute animal model of disease to analyze leptospirosis in male and female hamsters infected side by side with low but increasing doses of Leptospira interrogans serovar Copenhageni.
Bacterial InfectionsMrpJ Directly Regulates Proteus mirabilis Virulence Factors, Including Fimbriae and Type VI Secretion, during Urinary Tract Infection...Proteus mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs) and urolithiasis. The transcriptional regulator MrpJ inversely modulates two critical aspects of P. mirabilis UTI progression: fimbria-mediated attachment and flagellum-mediated motility.
Bacterial InfectionsEffect of Hypoxia on the Pathogenesis of Acinetobacter baumannii and Pseudomonas aeruginosa In Vitro and in Murine Experimental Models of InfectionHypoxia modulates bacterial virulence and the inflammation response through hypoxia-inducible factor 1α (HIF-1α). Here we study the influence of hypoxia on Acinetobacter baumannii and Pseudomonas aeruginosa infections.
Host Response and Inflammation
Host Response and Inflammation | SpotlightRole of Common γ-Chain Cytokines in Lung Interleukin-22 Regulation after Acute Exposure to Aspergillus fumigatusHumans are constantly exposed to the opportunistic mold Aspergillus fumigatus, and disease caused by this pathogen is often determined by the magnitude of local and systemic immune responses. We have previously shown a protective role for interleukin-22 (IL-22) after acute A. fumigatus exposure....
Host Response and InflammationMycobacterium tuberculosis Lipoprotein and Lipoglycan Binding to Toll-Like Receptor 2 Correlates with Agonist Activity and Functional OutcomesMycobacterium tuberculosis causes persistent infection due to its ability to evade host immune responses. M. tuberculosis induces Toll-like receptor 2 (TLR2) signaling, which influences immune responses to M. tuberculosis.
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Host Response and InflammationDifferential Immune Phenotypes in Human Monocytes Induced by Non-Host-Adapted Salmonella enterica Serovar Choleraesuis and Host-Adapted S. TyphimuriumWe studied the effects of two Salmonella enterica serovar Typhimurium (host-adapted) strains (14028 and 4/74) and three S. Choleraesuis (non-host-adapted) strains (A50, A45, and B195) in human monocytes between 2 and 24 h postinfection (p.i.) to investigate whether differences in immune response may explain the much higher prevalence of sepsis in individuals...
Host Response and InflammationDepletion of Complement Enhances the Clearance of Brucella abortus in MiceBrucellosis is a bacterial disease of animals and humans. Brucella abortus barely activates the innate immune system at the onset of infection, and this bacterium is resistant to the microbicidal action of complement.
Fungal and Parasitic Infections
Fungal and Parasitic InfectionsChronic Toxoplasma gondii Infection Induces Anti-N-Methyl-d-Aspartate Receptor Autoantibodies and Associated Behavioral Changes and NeuropathologyAnti-NMDA receptor (NMDAR) autoantibodies have been postulated to play a role in the pathogenesis of NMDAR hypofunction, which contributes to the etiology of psychotic symptoms. Toxoplasma gondii is a pathogen implicated in psychiatric disorders and associated with elevation of NMDAR autoantibodies.
Fungal and Parasitic Infections | SpotlightYeast and Filaments Have Specialized, Independent Activities in a Zebrafish Model of Candida albicans InfectionCandida albicans dimorphism is a crucial virulence factor during invasive candidiasis infections, which claim the lives of nearly one-half of those afflicted. It has long been believed that filaments drive tissue invasion and yeast mediates bloodstream dissemination, but observation of these activities during infection has been prevented by technical limitations....
Fungal and Parasitic InfectionsFoxp3+ T Regulatory Cells as a Potential Target for Immunotherapy against Primary Infection with Echinococcus multilocularis EggsAlveolar echinococcosis (AE) is a lethal disease caused by infection with the metacestode stage of the helminth Echinococcus multilocularis, which develops into a tumorlike mass in susceptible intermediate hosts. The growth potential of this parasite stage is directly linked to the nature of the surrounding periparasitic immune-mediated processes.
Microbial Immunity and Vaccines
Microbial Immunity and VaccinesAdjuvant Potential of Poly-α-l-Glutamine from the Cell Wall of Mycobacterium tuberculosisNovel adjuvants are in demand for improving the efficacy of human vaccines. The immunomodulatory properties of Mycobacterium tuberculosis cell wall components have been highlighted in the formulation of complete Freund's adjuvant (CFA).
Microbial Immunity and VaccinesEvaluation of Adenylate Cyclase Toxoid Antigen in Acellular Pertussis Vaccines by Using a Bordetella pertussis Challenge Model in MiceBordetella pertussis is the primary causative agent of pertussis (whooping cough), which is a respiratory infection that leads to a violent cough and can be fatal in infants. There is a need to develop more effective vaccines because of the resurgence of cases of pertussis in the United States since the switch from the whole-cell pertussis vaccines (wP) to the...
Molecular Genomics
Molecular GenomicsGenome Plasticity of agr-Defective Staphylococcus aureus during Clinical InfectionTherapy for bacteremia caused by Staphylococcus aureus is often ineffective, even when treatment conditions are optimal according to experimental protocols. Adapted subclones, such as those bearing mutations that attenuate agr-mediated virulence activation, are associated with persistent infection and patient mortality.
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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.