Salmonella
Microbial Immunity and Vaccines | SpotlightSalmonella Paratyphi A Outer Membrane Vesicles Displaying Vi Polysaccharide as a Multivalent Vaccine against Enteric FeverTyphoid and paratyphoid fevers have a high incidence worldwide and coexist in many geographical areas, especially in low-middle-income countries (LMIC) in South and Southeast Asia. There is extensive consensus on the urgent need for better and affordable vaccines against systemic Salmonella infections.
Cellular Microbiology: Pathogen-Host Cell Molecular Interactions(p)ppGpp-Dependent Regulation of the Nucleotide Hydrolase PpnN Confers Complement Resistance in Salmonella enterica Serovar TyphimuriumThe stringent response is an essential mechanism of metabolic reprogramming during environmental stress that is mediated by the nucleotide alarmones guanosine tetraphosphate and pentaphosphate [(p)ppGpp]. In addition to physiological adaptations, (p)ppGpp also regulates virulence programs in pathogenic bacteria, including Salmonella enterica serovar Typhimurium. S...
Host Response and InflammationFailure of CD4 T Cell-Deficient Hosts To Control Chronic Nontyphoidal Salmonella Infection Leads to Exacerbated Inflammation, Chronic Anemia, and Altered MyelopoiesisImmunocompromised patients are more susceptible to recurrent nontyphoidal Salmonella (NTS) bacteremia. A key manifestation of HIV infection is the loss of CD4 T cells, which are crucial for immunity to Salmonella infection. We characterized the consequences of CD4 T cell depletion in mice where virulent Salmonella establish chronic infection, similar to chronic NTS disease in humans. Salmonella-...
MinireviewAntibodies and Protection in Systemic Salmonella Infections: Do We Still Have More Questions than Answers?Salmonella causes grave systemic infections in humans and other animals and provides a paradigm for other diseases in which the bacteria have both intracellular and extracellular lifestyles. New generations of vaccines rely on the essential contribution of the antibody responses for their protection. The quality, antigen specificity, and functions associated with...
Molecular PathogenesisThe Salmonella LysR Family Regulator RipR Activates the SPI-13-Encoded Itaconate Degradation ClusterItaconate is a dicarboxylic acid that inhibits the isocitrate lyase enzyme of the bacterial glyoxylate shunt. Activated macrophages have been shown to produce itaconate, suggesting that these immune cells may employ this metabolite as a weapon against invading bacteria. Here, we demonstrate that in vitro, itaconate can exhibit bactericidal effects under acidic conditions similar to the pH of a macrophage phagosome. In parallel...
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 InflammationSalmonella enterica Infection of Murine and Human Enteroid-Derived Monolayers Elicits Differential Activation of Epithelium-Intrinsic InflammasomesRecent studies have determined that inflammasome signaling plays an important role in driving intestinal epithelial cell (IEC) responses to bacterial infections, such as Salmonella enterica serovar Typhimurium. There are two primary inflammasome pathways, canonical (involving caspase-1) and noncanonical (involving caspase-4 and -5 in humans and caspase-11 in mice)....
Molecular PathogenesisA Peptidoglycan Amidase Activator Impacts Salmonella enterica Serovar Typhimurium Gut InfectionSalmonella enterica serovar Typhimurium is an important foodborne pathogen that causes diarrhea. S. Typhimurium elicits inflammatory responses and colonizes the gut lumen by outcompeting the microbiota. Although evidence is accumulating with regard to the underlying mechanism, the infectious stage...
Bacterial InfectionsAtypical Salmonella enterica Serovars in Murine and Human Macrophage Infection ModelsNontyphoidal Salmonella species are globally disseminated pathogens and are the predominant cause of gastroenteritis. The pathogenesis of salmonellosis has been extensively studied using in vivo murine models and cell lines, typically challenged with Salmonella enterica serovar Typhimurium. Although...
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...