Table of Contents
Spotlight
Minireviews
MinireviewType 3 Immunity during Clostridioides difficile Infection: Too Much of a Good Thing?Clostridioides (formerly known as Clostridium) difficile is the leading cause of hospital-acquired gastrointestinal infections in the United States and one of three urgent health care threats identified by the Centers for Disease Control and Prevention. C. difficile disease is mediated by the production of toxins that disrupt the epithelial...
MinireviewBiomarkers for Detecting Resilience against Mycobacterial Disease in AnimalsParatuberculosis and bovine tuberculosis are two mycobacterial diseases of ruminants which have a considerable impact on livestock health, welfare, and production. These are chronic “iceberg” diseases which take years to manifest and in which many subclinical cases remain undetected. Suggested biomarkers to detect infected or diseased animals are numerous and include cytokines, peptides, and expression of specific genes; however, these...
Molecular Pathogenesis
Molecular PathogenesisProminent Binding of Human and Equine Fibrinogen to Streptococcus equi subsp. zooepidemicus Is Mediated by Specific SzM Types and Is a Distinct Phenotype of Zoonotic IsolatesStreptococcus equi subsp. zooepidemicus is an important pathogen in horses that causes severe diseases such as pneumonia and abortion. Furthermore, it is a zoonotic agent, and contact with horses is a known risk factor. In this study, we investigated the working hypothesis that the zoonotic potential varies among...
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsNo Evidence of Apoptotic Response of the Potato Psyllid Bactericera cockerelli to “Candidatus Liberibacter solanacearum” at the Gut Interface“Candidatus Liberibacter solanacearum” is a pathogen transmitted by the potato psyllid Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) in a persistent manner. In this study, we investigated the molecular interaction between “Ca. Liberibacter solanacearum” and the potato psyllid at the gut interface. Specifically, we focused on the apoptotic response of potato psyllids to the infection by two “Ca....
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsMutation of the Transcriptional Regulator YtoI Rescues Listeria monocytogenes Mutants Deficient in the Essential Shared Metabolite 1,4-Dihydroxy-2-Naphthoate (DHNA)Listeria monocytogenes, a Gram-positive, facultative intracellular pathogen, survives and replicates in the cytosol of host cells. Synthesis of 1,4-dihydroxy-2-naphthoate (DHNA), an intermediate of menaquinone biosynthesis, is essential for cytosolic survival of L. monocytogenes independent from its...
Cellular Microbiology: Pathogen-Host Cell Molecular InteractionsHuman Enteric Defensin 5 Promotes Shigella Infection of MacrophagesHuman α-defensins are 3- to 5-kDa disulfide-bridged peptides with a multitude of antimicrobial activities and immunomodulatory functions. Recent studies show that human enteric α-defensin 5 (HD5), a host defense peptide important for intestinal homeostasis and innate immunity, aids the highly infectious enteropathogen Shigella in breaching the intestinal epithelium in vitro and in vivo.
Bacterial Infections
Bacterial Infections | SpotlightA Rare Opportunist, Morganella morganii, Decreases Severity of Polymicrobial Catheter-Associated Urinary Tract InfectionCatheter-associated urinary tract infections (CAUTIs) are common hospital-acquired infections and frequently polymicrobial, which complicates effective treatment. However, few studies experimentally address the consequences of polymicrobial interactions within the urinary tract, and the clinical significance of polymicrobial bacteriuria is not fully understood.
Bacterial InfectionsMycobacterium tuberculosis LipE Has a Lipase/Esterase Activity and Is Important for Intracellular Growth and In Vivo InfectionMycobacterium tuberculosis Rv3775 (LipE) was annotated as a putative lipase. However, its lipase activity has never been characterized, and its precise role in tuberculosis (TB) pathogenesis has not been thoroughly studied to date. We overexpressed and purified the recombinant LipE (rLipE) protein and demonstrated that LipE has a lipase/esterase activity. rLipE...
Bacterial InfectionsKlebsiella pneumoniae Expressing VIM-1 Metallo-β-Lactamase Is Resensitized to Cefotaxime via Thiol-Mediated Zinc ChelationAntibiotic-resistant Klebsiella pneumoniae isolates constitute a great clinical challenge. One important resistance mechanism in K. pneumoniae is the metallo-β-lactamases (MBLs), which require zinc for their function. Thus, zinc chelation could be a strategy to resensitize...
Bacterial Infections | SpotlightSalmonella enterica Serovar Typhimurium Uses PbgA/YejM To Regulate Lipopolysaccharide Assembly during BacteremiaSalmonella enterica serovar Typhimurium (S. Typhimurium) relies upon the inner membrane protein PbgA to enhance outer membrane (OM) integrity and promote virulence in mice. The PbgA transmembrane domain (residues 1 to 190) is essential for viability, while the periplasmic domain (residues 191 to 586) is dispensable. Residues within the basic region (residues...
Bacterial Infections | SpotlightSalmonella enterica Requires Lipid Metabolism Genes To Replicate in Proinflammatory Macrophages and MiceTo survive and replicate during infection, pathogens utilize different carbon and energy sources depending on the nutritional landscape of their host microenvironment. Salmonella enterica serovar Typhimurium is an intracellular bacterial pathogen that occupies diverse cellular niches. While it is clear that Salmonella Typhimurium requires access to glucose...
Host Response and Inflammation
Host Response and InflammationChlamydia psittaci-Infected Dendritic Cells Communicate with NK Cells via Exosomes To Activate Antibacterial ImmunityDendritic cells (DCs) and natural killer (NK) cells are critically involved in the early response against various bacterial microbes. Functional activation of infected DCs and NK cell-mediated gamma interferon (IFN-γ) secretion essentially contribute to the protective immunity against Chlamydia. How DCs and NK cells cooperate during the antichlamydial response is not fully understood.
Host Response and InflammationTranscriptional and Pathological Host Responses to Coinfection with Virulent or Attenuated Mycoplasma gallisepticum and Low-Pathogenic Avian Influenza A Virus in ChickensThe avian pathogen Mycoplasma gallisepticum, the etiological agent of chronic respiratory disease in chickens, exhibits enhanced pathogenesis in the presence of a copathogen such as low-pathogenic avian influenza virus (LPAIV).
Host Response and InflammationDivergent Antigen-Specific Cellular Immune Responses during Asymptomatic Subclinical and Clinical States of Disease in Cows Naturally Infected with Mycobacterium avium subsp. paratuberculosisInfection of the host with Mycobacterium avium subsp. paratuberculosis results in chronic and progressive enteritis that traverses both subclinical and clinical stages. The mechanism(s) for the shift from an asymptomatic subclinical disease state to advanced clinical disease is not fully understood.
Host Response and Inflammation | SpotlightA Loss-of-Function Mutation in the Integrin Alpha L (Itgal) Gene Contributes to Susceptibility to Salmonella enterica Serovar Typhimurium Infection in Collaborative Cross Strain CC042Salmonella is an intracellular bacterium found in the gastrointestinal tract of mammalian, avian, and reptilian hosts. Mouse models have been extensively used to model in vivo distinct aspects of human Salmonella infections and have led to the identification of several host susceptibility genes. We have investigated the susceptibility of Collaborative Cross strains to intravenous infection with...
Host Response and InflammationEarly Growth Response 1 Deficiency Protects the Host against Pseudomonas aeruginosa Lung InfectionPseudomonas aeruginosa is an opportunistic pathogen that is a common cause of nosocomial infections. The molecular mechanisms governing immune responses to P. aeruginosa infection remain incompletely defined. Early growth response 1 (Egr-1) is a zinc-finger transcription factor that controls...
Host Response and InflammationThe Nature of Antibacterial Adaptive Immune Responses against Staphylococcus aureus Is Dependent on the Growth Phase and Extracellular PeptidoglycanStaphylococcus aureus has evolved different strategies to evade the immune response, which play an important role in its pathogenesis. The bacteria express and shed various cell wall components and toxins during different stages of growth that may affect the protective T cell responses to extracellular and intracellular...
Microbial Immunity and Vaccines
Microbial Immunity and VaccinesConstruction and Characterization of the Mycobacterium tuberculosis sigE fadD26 Unmarked Double Mutant as a Vaccine CandidateDespite the great increase in the understanding of the biology and pathogenesis of Mycobacterium tuberculosis achieved by the scientific community in recent decades, tuberculosis (TB) still represents one of the major threats to global human health.
Microbial Immunity and Vaccines | SpotlightClearance of Staphylococcus aureus from In Vivo Models of Chronic Infection by Immunization Requires Both Planktonic and Biofilm AntigensStaphylococcus aureus is a causative agent of chronic biofilm-associated infections that are recalcitrant to resolution by the immune system or antibiotics. To combat these infections, an antistaphylococcal, biofilm-specific quadrivalent vaccine against an osteomyelitis model in rabbits has previously been developed and shown to be effective at eliminating biofilm-...
Microbial Immunity and VaccinesToll-Like Receptor 2 (TLR2) and TLR4 Mediate the IgA Immune Response Induced by Mycoplasma hyopneumoniaeIgA plays an important role in mucosal immunity against infectious pathogens; however, the molecular mechanism of IgA secretion in response to infection remains largely unknown, particularly in Mycoplasma spp. In this study, we found that the levels of IgA in the peripheral blood serum, bronchoalveolar lavage fluid, nasal mucosa, trachea, hilar lymph nodes, and lung...
Host-Associated Microbial Communities
Host-Associated Microbial CommunitiesDysregulation of Intestinal Microbiota Elicited by Food Allergy Induces IgA-Mediated Oral DysbiosisFood allergy is a life-threatening response to specific foods, and microbiota imbalance (dysbiosis) in gut is considered a cause of this disease. Meanwhile, the host immune response also plays an important role in the disease. Notably, interleukin 33 (IL-33) released from damaged or necrotic intestinal epithelial cells facilitates IL-2-producing CD4 helper T (Th2) responses. However, causal relationships between the gut and oral...
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