Spotlight
Molecular Pathogenesis
Molecular PathogenesisSingle Amino Acid Replacements in RocA Disrupt Protein-Protein Interactions To Alter the Molecular Pathogenesis of Group A StreptococcusGroup A Streptococcus (GAS) is a human-specific pathogen and major cause of disease worldwide. The molecular pathogenesis of GAS, like many pathogens, is dependent on the coordinated expression of genes encoding different virulence factors. The control of virulence regulator/s...
Molecular PathogenesisThe Twin-Arginine Translocation System Is Important for Stress Resistance and Virulence of Brucella melitensisBrucella, the causative agent of brucellosis, is a stealthy intracellular pathogen that is highly pathogenic to a range of mammals, including humans. The twin-arginine translocation (Tat) pathway transports folded proteins across the cytoplasmic membrane and has been implicated in virulence in many bacterial pathogens. However, the roles of the Tat system and related substrates in Brucella remain unclear. We report...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCoxiella burnetii-Infected NK Cells Release Infectious Bacteria by DegranulationNatural killer (NK) cells are critically involved in the early immune response against various intracellular pathogens, including Coxiella burnetii and Chlamydia psittaci. Chlamydia-infected NK cells functionally mature, induce cellular immunity, and protect themselves by killing the...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsDual Host-Intracellular Parasite Transcriptome of Enucleated Cells Hosting Leishmania amazonensis: Control of Half-Life of Host Cell Transcripts by the ParasiteEnucleated cells or cytoplasts (cells whose nucleus is removed in vitro) represent an unexplored biological model for intracellular infection studies due to the abrupt interruption of nuclear processing and new RNA synthesis by the host cell in response to pathogen entry. Using enucleated fibroblasts hosting the protozoan parasite Leishmania amazonensis, we...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsDistinct Mycoplasma pneumoniae Interactions with Sulfated and Sialylated ReceptorsMycoplasma pneumoniae is a cell wall-less bacterial pathogen of the conducting airways, causing bronchitis and atypical or “walking” pneumonia in humans. M. pneumoniae recognizes sialylated and sulfated oligosaccharide receptors to colonize the respiratory tract, but the contribution of the latter...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCigarette Smoke Exposure Promotes Virulence of Pseudomonas aeruginosa and Induces Resistance to Neutrophil KillingIt is widely known that cigarette smoke damages host defenses and increases susceptibility to bacterial infections. Pseudomonas aeruginosa, a Gram-negative bacterium that commonly colonizes the airways of smokers and patients with chronic lung disease, can cause pneumonia and sepsis and can trigger exacerbations of lung diseases....
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsCoinfection with Porcine Circovirus Type 2 (PCV2) and Streptococcus suis Serotype 2 (SS2) Enhances the Survival of SS2 in Swine Tracheal Epithelial Cells by Decreasing Reactive Oxygen Species ProductionPorcine circovirus type 2 (PCV2) and Streptococcus suis serotype 2 (SS2) clinical coinfection cases have been frequently detected. The respiratory epithelium plays a crucial role in host defense against a variety of inhaled pathogens. Reactive oxygen species (ROS) are involved in killing of bacteria and host immune response. The aim of this study is to assess whether...
Bacterial Infections
Bacterial InfectionsAnimal Model To Study Klebsiella pneumoniae Gastrointestinal Colonization and Host-to-Host TransmissionAn important yet poorly understood facet of the life cycle of a successful pathogen is host-to-host transmission. Hospital-acquired infections (HAI) resulting from the transmission of drug-resistant pathogens affect hundreds of millions of patients worldwide. Klebsiella pneumoniae, a Gram-negative bacterium, is notorious for causing HAI, with many of these infections...
Bacterial InfectionsEffects of Immunomodulatory Drug Fingolimod (FTY720) on Chlamydia Dissemination and PathogenesisFingolimod (FTY720), an FDA-approved immunomodulatory drug for treating multiple sclerosis, is an agonist of sphingosine-1-phosphate receptor (S1PR), which has been used as a research tool for inhibiting immune cell trafficking. FTY720 was recently reported to inhibit Chlamydia dissemination. Since genital Chlamydia spreading to the gastrointestinal tract correlated with its pathogenicity in the upper genital tract, we...
Bacterial InfectionsThree-Dimensional In Vitro Staphylococcus aureus Abscess Communities Display Antibiotic Tolerance and Protection from Neutrophil ClearanceStaphylococcus aureus is a prominent human pathogen in bone and soft-tissue infections. Pathophysiology involves abscess formation, which consists of central staphylococcal abscess communities (SACs), surrounded by a fibrin pseudocapsule and infiltrating immune cells. Protection against the ingress of immune cells such as neutrophils, or tolerance to antibiotics,...
Bacterial InfectionsClarithromycin Exerts an Antibiofilm Effect against Salmonella enterica Serovar Typhimurium rdar Biofilm Formation and Transforms the Physiology towards an Apparent Oxygen-Depleted Energy and Carbon MetabolismUpon biofilm formation, production of extracellular matrix components and alteration in physiology and metabolism allows bacteria to build up multicellular communities which can facilitate nutrient acquisition during unfavorable conditions and provide protection toward various forms of environmental stresses to individual cells. Thus, bacterial cells within biofilms become tolerant against antimicrobials and the immune system. In the...
Host Response and Inflammation
Host Response and Inflammation | SpotlightRegulatory T Cells Contribute to Resistance against Lyme ArthritisThe symptoms of Lyme disease are caused by inflammation induced by species of the Borrelia burgdorferi sensu lato complex. The various presentations of Lyme disease in the population suggest that differences exist in the intensity and regulation of the host response to the spirochete. Previous work has described correlations between the presence of regulatory...
Host Response and InflammationEnterococcus faecalis Induces Differentiation of Immune-Aberrant Dendritic Cells from Murine Bone Marrow-Derived Stem CellsEnterococcus faecalis, long implicated in serious systemic infections and failure of root canal treatment, is a persistent inhabitant of oral periapical lesions. Dendritic cells (DCs) and other innate immune cells patrol the oral mucosa for infecting microbes. Dendritic cells are efficient at capturing microbes when immature, whereupon they can transform into potent...
Fungal and Parasitic Infections
Fungal and Parasitic InfectionsLimited Role of Mincle in the Host Defense against Infection with Cryptococcus deneoformansCryptococcus deneoformans is an opportunistic fungal pathogen that frequently causes fatal meningoencephalitis in patients with impaired cell-mediated immune responses such as AIDS. Caspase-associated recruitment domain 9 (CARD9) plays a critical role in the host defense against cryptococcal infection, suggesting the involvement of one or more C-type lectin receptors...
Microbial Immunity and Vaccines
Microbial Immunity and VaccinesCross-Reactivity, Epitope Mapping, and Potency of Monoclonal Antibodies to Class 5 Fimbrial Tip Adhesins of Enterotoxigenic Escherichia coliEnterotoxigenic Escherichia coli (ETEC) is a leading diarrheagenic bacterial pathogen among travelers and children in resource-limited regions. Adherence to host intestinal cells mediated by ETEC fimbriae is believed to be a critical first step in ETEC pathogenesis. These fimbriae are categorized into related classes based on sequence similarity, with members of the...
Microbial Immunity and VaccinesEvaluation of the Immunogenicity and Protective Efficacy of an Enterotoxigenic Escherichia coli CFA/I Adhesin–Heat-Labile Toxin ChimeraRecent efforts to develop an enterotoxigenic Escherichia coli (ETEC) vaccine have focused on the antigenically conserved tip adhesins of colonization factors. We showed previously that intranasal immunization with dsc19CfaE, a soluble variant of the in cis donor strand-complemented tip adhesin of a colonization factor of the class 5 family (CFA/I)...
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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.