Spotlight
Minireview
MinireviewEosinophils and Macrophages within the Th2-Induced Granuloma: Balancing Killing and Healing in a Tight SpaceGranuloma formation is a key host immune response generated to confine invading pathogens and limit extensive host damage. It consists of an accumulation of host immune cells around a pathogen. This host response has been extensively studied in the context of inflammatory diseases. However, there is much less known about Th2-type granulomas generated in response to parasitic worms.
Molecular Pathogenesis
Molecular PathogenesisStreptococcus oralis subsp. dentisani Produces Monolateral Serine-Rich Repeat Protein Fibrils, One of Which Contributes to Saliva Binding via Sialic AcidOur studies reveal that the oral colonizer and cause of infective endocarditis Streptococcus oralis subsp. dentisani displays a striking monolateral distribution of surface fibrils. Furthermore, our data suggest that these fibrils impact the structure of adherent bacterial chains.
Molecular PathogenesisTissue Tropism in Streptococcal Infection: Wild-Type M1T1 Group A Streptococcus Is Efficiently Cleared by Neutrophils Using an NADPH Oxidase-Dependent Mechanism in the Lung but Not in the SkinGroup A Streptococcus (GAS) commonly causes pharyngitis and skin infections. Little is known why streptococcal pharyngitis usually does not lead to pneumonia and why the skin is a favorite niche for GAS. To partially address these questions, the effectiveness of neutrophils in clearing wild-type (wt) M1T1 GAS strain MGAS2221 from the lung and from the skin was examined in murine models of intratracheal pneumonia and...
Molecular PathogenesisPeptidyl-Prolyl Isomerase ppiB Is Essential for Proteome Homeostasis and Virulence in Burkholderia pseudomalleiBurkholderia pseudomallei is the causative agent of melioidosis, a disease endemic to Southeast Asia and northern Australia. Mortality rates in these areas are high even with antimicrobial treatment, and there are few options for effective therapy. Therefore, there is a need to identify antibacterial targets for the development of novel treatments. Cyclophilins are a...
Molecular PathogenesisThe Ferric Uptake Regulator Represses Type VI Secretion System Function by Binding Directly to the clpV Promoter in Salmonella enterica Serovar TyphimuriumType VI secretion systems (T6SSs) are highly conserved and complex protein secretion systems that deliver effector proteins into eukaryotic hosts or other bacteria. T6SSs are regulated precisely by a variety of regulatory systems, which enables bacteria to adapt to varied environments.
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsAcquisition of IgG to ICAM-1-Binding DBLβ Domains in the Plasmodium falciparum Erythrocyte Membrane Protein 1 Antigen Family Varies between Groups A, B, and CPlasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important malaria virulence factor. The protein family can be divided into clinically relevant subfamilies. ICAM-1-binding group A PfEMP1 proteins also bind endothelial protein C receptor and have been associated with cerebral malaria in children. IgG to these PfEMP1 proteins is acquired later in life...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsToll-Like Receptor 3 Deficiency Leads to Altered Immune Responses to Chlamydia trachomatis Infection in Human Oviduct Epithelial CellsReproductive tract pathology caused by Chlamydia trachomatis infection is an important global cause of human infertility. To better understand the mechanisms associated with Chlamydia-induced genital tract pathogenesis in humans, we used CRISPR genome editing to disrupt Toll-like receptor 3 (TLR3) function in the human oviduct epithelial (hOE) cell line OE-E6...
Bacterial Infections
Bacterial InfectionsEffect of Macrolide and Rifampin Resistance on Fitness of Rhodococcus equi during Intramacrophage Replication and In VivoThe soil-dwelling, saprophytic actinomycete Rhodococcus equi is a facultative intracellular pathogen of macrophages and causes severe bronchopneumonia when inhaled by susceptible foals. Standard treatment for R. equi disease is dual-antimicrobial therapy with a macrolide and rifampin. Thoracic...
Bacterial Infections | SpotlightGenerality of Post-Antimicrobial Treatment Persistence of Borrelia burgdorferi Strains N40 and B31 in Genetically Susceptible and Resistant Mouse StrainsA basic feature of infection caused by Borrelia burgdorferi, the etiological agent of Lyme borreliosis, is that persistent infection is the rule in its many hosts. The ability to persist and evade host immune clearance poses a challenge to effective antimicrobial treatment. A link between therapy failure and the presence of persister cells has started to emerge.
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Bacterial InfectionsIron-Sulfur Cluster Repair Contributes to Yersinia pseudotuberculosis Survival within Deep TissuesTo successfully colonize host tissues, bacteria must respond to and detoxify many different host-derived antimicrobial compounds, such as nitric oxide (NO). NO has direct antimicrobial activity through attack on iron-sulfur (Fe-S) cluster-containing proteins. NO detoxification plays an important role in promoting bacterial survival, but it remains unclear if repair of Fe-S clusters is also important for bacterial survival within host...
Host Response and Inflammation
Host Response and InflammationFetal Weight Outcomes in C57BL/6J and C57BL/6NCrl Mice after Oral Colonization with Porphyromonas gingivalisPorphyromonas gingivalis is considered a keystone pathogen that contributes to the initiation and progression of periodontitis in humans. P. gingivalis has also been detected in human placentas associated with adverse pregnancy outcomes. The spread of...
Host Response and InflammationStaphylococcus aureus Lipoic Acid Synthesis Limits Macrophage Reactive Oxygen and Nitrogen Species Production To Promote Survival during InfectionMacrophages are critical mediators of innate immunity and must be overcome for bacterial pathogens to cause disease. The Gram-positive bacterium Staphylococcus aureus produces virulence factors that impede macrophages and other immune cells. We previously determined that production of the metabolic cofactor lipoic acid by the lipoic acid synthetase, LipA, blunts...
Host Response and InflammationLinezolid Attenuates Lethal Lung Damage during Postinfluenza Methicillin-Resistant Staphylococcus aureus PneumoniaPostinfluenza methicillin-resistant Staphylococcus aureus (MRSA) infection can quickly develop into severe, necrotizing pneumonia, causing over 50% mortality despite antibiotic treatments. In this study, we investigated the efficacy of antibiotic therapies and the impact of S. aureus alpha-toxin in...
Microbial Immunity and Vaccines
Microbial Immunity and VaccinesCoxiella burnetii Epitope-Specific T-Cell Responses in Patients with Chronic Q FeverInfection with Coxiella burnetii, the causative agent of Q fever, can result in life-threatening persistent infection. Reactogenicity hinders worldwide implementation of the only licensed human Q fever vaccine. We previously demonstrated long-lived immunoreactivity in individuals with past symptomatic and asymptomatic Coxiella infection (convalescents) to...
Microbial Immunity and VaccinesAntibody-Dependent, Gamma Interferon-Independent Sterilizing Immunity Induced by a Subunit Malaria VaccineThe development of effective malaria vaccines is hampered by incomplete understanding of the immunological correlates of protective immunity. Recently, the moderate clinical efficacy of the Plasmodium falciparum circumsporozoite protein (CSP)-based RTS,S/AS01E vaccine in phase 3 studies highlighted the urgency to design and test more efficacious next-...
Microbial Immunity and VaccinesA Cross-Reactive Protein Vaccine Combined with PCV-13 Prevents Streptococcus pneumoniae- and Haemophilus influenzae-Mediated Acute Otitis MediaAcute otitis media is one of the most common childhood infections worldwide. Currently licensed vaccines against the common otopathogen Streptococcus pneumoniae target the bacterial capsular polysaccharide and confer no protection against nonencapsulated strains or capsular types outside vaccine coverage. Mucosal infections such as acute otitis media remain prevalent...
Microbial Immunity and VaccinesA Recombinant Attenuated Yersinia pseudotuberculosis Vaccine Delivering a Y. pestis YopENt138-LcrV Fusion Elicits Broad Protection against Plague and Yersiniosis in MiceIn this study, a novel recombinant attenuated Yersinia pseudotuberculosis PB1+ strain (χ10069) engineered with ΔyopK ΔyopJ Δasd triple mutations was used to deliver a Y. pestis fusion protein, YopE amino acid 1 to 138-LcrV (YopENt138-LcrV), to Swiss Webster mice...
Microbial Immunity and VaccinesCommensal Microbes Affect Host Humoral Immunity to Bordetella pertussis InfectionAs important players in the host defense system, commensal microbes and the microbiota influence multiple aspects of host physiology. Bordetella pertussis infection is highly contagious among humans. However, the roles of the microbiota in B. pertussis pathogenesis are poorly understood. Here, we...
Microbial Immunity and VaccinesInterleukin-10 (IL-10) Produced by Mutant Toxic Shock Syndrome Toxin 1 Vaccine-Induced Memory T Cells Downregulates IL-17 Production and Abrogates the Protective Effect against Staphylococcus aureus InfectionDevelopment of long-term memory is crucial for vaccine-induced adaptive immunity against infectious diseases such as Staphylococcus aureus infection. Toxic shock syndrome toxin 1 (TSST-1), one of the superantigens produced by S. aureus, is a possible vaccine candidate against infectious diseases...
Microbial Immunity and Vaccines | SpotlightBordetella Colonization Factor A (BcfA) Elicits Protective Immunity against Bordetella bronchiseptica in the Absence of an Additional AdjuvantBordetella bronchiseptica is an etiologic agent of respiratory diseases in animals and humans. Despite the widespread use of veterinary B. bronchiseptica vaccines, there is limited information on their composition and relative efficacy and on the immune responses that they elicit. Furthermore, human...
Molecular Genomics
Molecular GenomicsThe Complete Genome of the Atypical Enteropathogenic Escherichia coli Archetype Isolate E110019 Highlights a Role for Plasmids in Dissemination of the Type III Secreted Effector EspTEnteropathogenic Escherichia coli (EPEC) is a leading cause of moderate to severe diarrhea among young children in developing countries, and EPEC isolates can be subdivided into two groups. Typical EPEC (tEPEC) bacteria are characterized by the presence of both the locus of enterocyte effacement (LEE) and the plasmid-encoded bundle-forming pilus (BFP), which are...
Host-Associated Microbial Communities
Host-Associated Microbial CommunitiesInterference with Pseudomonas aeruginosa Quorum Sensing and Virulence by the Mycobacterial Pseudomonas Quinolone Signal Dioxygenase AqdC in Combination with the N-Acylhomoserine Lactone Lactonase QsdAThe nosocomial pathogen Pseudomonas aeruginosa regulates its virulence via a complex quorum sensing network, which, besides N-acylhomoserine lactones, includes the alkylquinolone signal molecules 2-heptyl-3-hydroxy-4(1H)-quinolone (Pseudomonas quinolone signal [PQS]) and 2-heptyl-4(1H)-quinolone (HHQ)....
Host-Associated Microbial CommunitiesMulti-omics Analyses Reveal Synergistic Carbohydrate Metabolism in Streptococcus mutans-Candida albicans Mixed-Species BiofilmsCandida albicans, a major opportunistic fungal pathogen, is frequently found together with Streptococcus mutans in dental biofilms associated with severe childhood caries (tooth decay), a prevalent pediatric oral disease. However, the impact of this cross-kingdom relationship on...
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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.