|Yersinia scanned with electron micrograph|
Smith & Thal 1965
Yersinia pseudotuberculosis is a Gram-negative bacterium that causes Far East scarlet-like fever in humans, who occasionally get infected zoonotically, most often through the food-borne route.Animals are also infected by Y. pseudotuberculosis. The bacterium is urease positive.
Far East scarlet-like fever or scarlatinoid fever is an infectious disease caused by the gram negative bacillus Yersinia pseudotuberculosis. In Japan it is called Izumi fever.
Zoonoses are infectious diseases that can be naturally transmitted between animals and humans.
Ureases, functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous bacteria, fungi, algae, plants, and some invertebrates, as well as in soils, as a soil enzyme. They are nickel-containing metalloenzymes of high molecular weight.
In animals, Y. pseudotuberculosis can cause tuberculosis-like symptoms, including localized tissue necrosis and granulomas in the spleen, liver, and lymph nodes.
Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. Tuberculosis generally affects the lungs, but can also affect other parts of the body. Most infections do not have symptoms, in which case it is known as latent tuberculosis. About 10% of latent infections progress to active disease which, if left untreated, kills about half of those affected. The classic symptoms of active TB are a chronic cough with blood-containing sputum, fever, night sweats, and weight loss. It was historically called "consumption" due to the weight loss. Infection of other organs can cause a wide range of symptoms.
Necrosis is a form of cell injury which results in the premature death of cells in living tissue by autolysis.
The spleen is an organ found in virtually all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes from Ancient Greek σπλήν (splḗn).
In humans, symptoms of Far East scarlet-like fever are similar to those of infection with Yersinia enterocolitica (fever and right-sided abdominal pain), except that the diarrheal component is often absent, which sometimes makes the resulting condition difficult to diagnose. Y. pseudotuberculosis infections can mimic appendicitis, especially in children and younger adults, and, in rare cases, the disease may cause skin complaints (erythema nodosum), joint stiffness and pain (reactive arthritis), or spread of bacteria to the blood (bacteremia).
Yersinia enterocolitica is a Gram-negative bacillus-shaped bacterium, belonging to the family Enterobacteriaceae. It is motile at temperatures of 22–29°C, but becomes nonmotile at normal human body temperature.Y. enterocolitica infection causes the disease yersiniosis, which is an animal-borne disease occurring in humans, as well as in a wide array of animals such as cattle, deer, pigs, and birds. Many of these animals recover from the disease and become carriers; these are potential sources of contagion despite showing no signs of disease. The bacterium infects the host by sticking to its cells using trimeric autotransporter adhesins.
Appendicitis is inflammation of the appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. However, approximately 40% of people do not have these typical symptoms. Severe complications of a ruptured appendix include widespread, painful inflammation of the inner lining of the abdominal wall and sepsis.
Erythema nodosum (EN), also known as subacute migratory panniculitis of Vilanova and Piñol, is an inflammatory condition characterized by inflammation of the fat cells under the skin, resulting in tender red nodules or lumps that are usually seen on both shins. It can be caused by a variety of conditions, and typically resolves spontaneously within 30 days. It is common in young people between 12–20 years of age.
Far East scarlet-like fever usually becomes apparent five to 10 days after exposure and typically lasts one to three weeks without treatment. In complex cases or those involving immunocompromised patients, antibiotics may be necessary for resolution; ampicillin, aminoglycosides, tetracycline, chloramphenicol, or a cephalosporin may all be effective.
Ampicillin is an antibiotic used to prevent and treat a number of bacterial infections, such as respiratory tract infections, urinary tract infections, meningitis, salmonellosis, and endocarditis. It may also be used to prevent group B streptococcal infection in newborns. It is used by mouth, by injection into a muscle, or intravenously. Like all antibiotics, it is not useful for the treatment of viral infections.
Tetracycline, sold under the brand name Sumycin among others, is an antibiotic used to treat a number of infections. This includes acne, cholera, brucellosis, plague, malaria, and syphilis. It is taken by mouth.
Chloramphenicol is an antibiotic useful for the treatment of a number of bacterial infections. This includes as an eye ointment to treat conjunctivitis. By mouth or by injection into a vein, it is used to treat meningitis, plague, cholera, and typhoid fever. Its use by mouth or by injection is only recommended when safer antibiotics cannot be used. Monitoring both blood levels of the medication and blood cell levels every two days is recommended during treatment.
The recently described syndrome "Izumi-fever" has been linked to infection with Y. pseudotuberculosis.
The symptoms of fever and abdominal pain mimicking appendicitis (actually from mesenteric lymphadenitis)associated with Y. pseudotuberculosis infection are not typical of the diarrhea and vomiting from classical food poisoning incidents. Although Y. pseudotuberculosis is usually only able to colonize hosts by peripheral routes and cause serious disease in immunocompromised individuals, if this bacterium gains access to the blood stream, it has an LD50 comparable to Y. pestis at only 10 CFU.
Genetically, the pathogen causing plague, Y. pestis , is very similar to Y. pseudotuberculosis. The plague appears to have evolved from Y. pseudotuberculosis about 1500 to 20,000 years ago.A 2015 paper in Cell argued for an older divergence.
To facilitate attachment, invasion, and colonization of its host, this bacterium possesses many virulence factors. Superantigens, bacterial adhesions, and the actions of Yops (which are bacterial proteins once thought to be "Yersinia outer membrane proteins") that are encoded on the "[plasmid] for Yersinia virulence" – commonly known as the pYV – cause host pathogenesis and allow the bacteria to live parasitically.
The 70-kb pYV is critical to Yersinia's pathogenicity, since it contains many genes known to encode virulence factors and its loss gives avirulence of all Yersinia species.A 26-kb "core region" in the pYV contains the ysc genes, which regulate the expression and secretion of Yops. Many Ysc proteins also amalgamate to form a type-III secretory apparatus, which secretes many Yops into the host cell cytoplasm with the assistance of the "translocation apparatus", constructed of YopB and YopD. The core region also includes yopN, yopB, yopD, tyeA, lcrG, and lcrV, which also regulate Yops gene expression and help to translocate secretory Yops to the target cell. For example, YopN and TyeA are positioned as a plug on the apparatus so only their conformational change, induced by their interaction with certain host cell membrane proteins, will cause the unblocking of the secretory pathway. Secretion is regulated in this fashion so that proteins are not expelled into the extracellular matrix and elicit an immune response. Since this pathway gives secretion selectivity, it is a virulence factor.
In contrast to the ysc and yop genes listed above, the Yops that act directly on host cells to cause cytopathologic effects – "effector Yops" – are encoded by pYV genes external to this core region.The sole exception is LcrV, which is also known as the "versatile Yop" for its two roles as an effector Yop and as a regulatory Yop. The combined function of these effector Yops permits the bacteria to resist internalization by immune and intestinal cells and to evade the bactericidal actions of neutrophils and macrophages. Inside the bacterium, these Yops are bound by pYV-encoded Sycs (specific Yop chaperones), which prevent premature interaction with other proteins and guide the Yops to a type-III secretory apparatus. In addition to the Syc-Yop complex, Yops are also tagged for type III secretion either by the first 60nt in their corresponding mRNA transcript or by their corresponding first 20 N-terminal amino acids. LcrV, YopQ, YopE, YopT, YopH, YpkA, YopJ, YopM, and YadA are all secreted by the type-III secretory pathway. LcrV inhibits neutrophil chemotaxis and cytokine production, allowing Y. pseudotuberculosis to form large colonies without inducing systemic failure and, with YopQ, contributes to the translocation process by bringing YopB and YopD to the eukaryotic cell membrane for pore-formation. By causing actin filament depolymerisation, YopE, YopT, and YpkA resist endocytosis by intestinal cells and phagocytosis while giving cytotoxic changes in the host cell. YopT targets Rho GTPase, commonly named "RhoA", and uncouples it from the membrane, leaving it in an inactive RhoA-GDI (guanine nucleotide dissociation inhibitor)-bound state whereas YopE and YpkA convert Rho proteins to their inactive GDP-bound states by expressing GTPase activity. YpkA also catalyses serine autophosporylation, so it may have regulatory functions in Yersinia or undermine host cell immune response signal cascades since YpkA is targeted to the cytoplasmic side of the host cell membrane. YopH acts on host focal adhesion sites by dephosphorylating several phosphotyrosine residues on focal adhesion kinase (FAK) and the focal adhesion proteins paxillin and p130. Since FAK phosphorylation is involved in uptake of yersiniae as well as T cell and B cell responses to antigen-binding, YopH elicits antiphagocytic and other anti-immune effects. YopJ, which shares an operon with YpkA, "...interferes with the mitogen-activated protein (MAP) kinase activities of c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase", leading to macrophage apoptosis. In addition, YopJ inhibits TNF-α release from many cell types, possibly through an inhibitory action on NF-κB, suppressing inflammation and the immune response. By secretion through a type III pathway and localization in the nucleus by a vesicle-associated, microtubule-dependent method, YopM may alter host cell growth by binding to RSK (ribosomal S6 kinase), which regulates cell cycle regulation genes. YadA has lost its adhesion, opsonisation-resisting, phagocytosis-resisting, and respiratory burst-resisting functions in Y. pseudotuberculosis due to a frameshift mutation by a single base-pair deletion in yadA in comparison to yadA in Y. enterocolitica, yet it still is secreted by type III secretion. The yop genes, yadA, ylpA, and the virC operon are considered the "Yop regulon" since they are coregulated by pYV-encoded VirF. virF is in turn thermoregulated. At 37 degrees Celsius, chromosomally encoded Ymo, which regulates DNA supercoiling around the virF gene, changes conformation, allowing for VirF expression, which then up-regulates the Yop regulon.
Y. pseudotuberculosis adheres strongly to intestinal cells via chromosomally encoded proteinsso that Yop secretion may occur, to avoid being removed by peristalsis, and to invade target host cells. A transmembrane protein, invasin, facilitates these functions by binding to host cell αβ1 integrins. Through this binding, the integrins cluster, thereby activating FAK, and causing a corresponding reorganization of the cytoskeleton. Subsequent internalization of bound bacteria occurs when the actin-depolymerising Yops are not being expressed. The protein encoded on the "attachment invasion locus" named Ail also bestows attachment and invasive abilities upon Yersiniae while interfering with the binding of complement on the bacterial surface. To increase binding specificity, the fibrillar pH6 antigen targets bacteria to target intestinal cells only when thermoinduced.
Certain strains of Yersinia pseudotuberculosis express a superantigenic exotoxin, YPM, or the Y. pseudotuberculosis-derived mitogen, from the chromosomal ypm gene.YPM specifically binds and causes the proliferation of T lymphocytes expressing the Vβ3, Vβ7, Vβ8, Vβ9, Vβ13.1, and Vβ13.2 variable regions with CD4+ T cell preference, although activation of some CD8+ T cells occurs. This T cell expansion can cause splenomegaly coupled with IL-2 and IL-4 overproduction. Since administering anti-TNF-α and anti-IFN-γ monoclonal antibodies neutralizes YPM toxicity in vivo, these cytokines are largely responsible for the damage caused indirectly by the exotoxin. Strains that carry the exotoxin gene are rare in Western countries, where the disease, when at all apparent, manifests itself largely with minor symptoms, whereas more than 95% of strains from Far Eastern countries contain ypm and are correlated with Izumi fever and Kawasaki disease. Although the superantigen poses the greatest threat to host health, all virulence factors contribute to Y. pseudotuberculosis viability in vivo and define the bacterium’s pathogenic characteristics. Y. pseudotuberculosis can live extracellularly due to its formidable mechanisms of phagocytosis and opsonisation resistance through the expression of Yops and the type III pathway; yet, by limited pYV action, it can populate host cells, especially macrophages, intracellularly to further evade immune responses and be disseminated throughout the body.
crystal structure of yersinia pseudotuberculosis-derived mitogen (ypm)
Yersinia pseudotuberculosis-derived mitogens (YpM) are superantigens, which are able to excessively activate T cells by binding to the T cell receptor. Since YpM can activate large numbers of the T cell population, this leads the release of inflammatory cytokines.
Members of this family of Yersinia pseudotuberculosis mitogens adopt a sandwich structure consisting of 9 strands in two beta sheets, in a jelly roll fold topology. YpM molecular weight is about 14 kDa. Structurally, it is unlike any other superantigen, but is remarkably similar to the tumour necrosis factor and viral capsid proteins. This suggests a possible evolutionary relationship.
Some highly homologous variants of YPM have been characterized, including YPMa, YPMb, and YPMc.
Numerous bacterial small non-coding RNA s have been identified to play regulatory functions. Some can regulate the virulence genes. 150 unannotated sRNAs were identified by sequencing of Y. pseudotuberculosis RNA libraries from bacteria grown at 26 °C and 37 °C, suggesting they may play a role in pathogenesis. By using single-molecule fluorescence in situ hybridisation smFISH technique it was shown that the number of YSR35 RNA increased 2.5 times upon temperature shift from 25 °C to 37 °C. Another study uncovered that a temperature-induced global reprogramming of central metabolic functions are likely to support intestinal colonization of the pathogen. Environmentally controlled regulatory RNAs coordinate control of metabolism and virulence allowing rapid adaptation and high flexibility during life-style changes. High-throughput RNA structure probing identified many thermoresponsive RNA structures.
Yersinia pestis is a gram-negative, nonmotile, rod-shaped coccobacillus, with no spores. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea. It causes the disease plague, which takes three main forms: pneumonic, septicemic and bubonic plagues. All three forms were responsible for a number of high-mortality epidemics throughout human history, including: the sixth century's Plague of Justinian; the Black Death, which accounted for the death of at least one-third of the European population between 1347 and 1353; and the Third Pandemic, sometimes referred to as the Modern Plague, which began in the late nineteenth century in China and spread by rats on steamboats claiming close to 10,000,000 lives. These plagues likely originated in China and were transmitted west via trade routes. Recent research indicates that the pathogen may have been the cause of what is described as the Neolithic Decline, when European populations declined significantly. This would push the date to much earlier and might be indicative of an origin in Europe rather than Eurasia.
Superantigens (SAgs) are a class of antigens that cause non-specific activation of T-cells resulting in polyclonal T cell activation and massive cytokine release. SAgs are produced by some pathogenic viruses and bacteria most likely as a defense mechanism against the immune system. Compared to a normal antigen-induced T-cell response where 0.0001-0.001% of the body’s T-cells are activated, these SAgs are capable of activating up to 20% of the body’s T-cells. Furthermore, Anti-CD3 and Anti-CD28 Antibodies (CD28-SuperMAB) have also shown to be highly potent superantigens.
Virulence factors are molecules produced by bacteria, viruses, fungi, and protozoa that add to their effectiveness and enable them to achieve the following:
Intimin is a virulence factor (adhesin) of EPEC and EHEC E. coli strains. It is an attaching and effacing (A/E) protein, which with other virulence factors is necessary and responsible for enteropathogenic and enterohaemorrhagic diarrhoea.
Mitogen-activated protein kinase 3, also known as p44MAPK and ERK1, is an enzyme that in humans is encoded by the MAPK3 gene.
Dual specificity mitogen-activated protein kinase kinase 2 is an enzyme that in humans is encoded by the MAP2K2 gene. It is more commonly known as MEK2, but has many alternative names including CFC4, MKK2, MAPKK2 and PRKMK2.
Dual specificity mitogen-activated protein kinase kinase 3 is an enzyme that in humans is encoded by the MAP2K3 gene.
Ribosomal protein S6 kinase alpha-1 is an enzyme that in humans is encoded by the RPS6KA1 gene.
Virulence-related outer membrane proteins are expressed in Gram-negative bacteria and are essential to bacterial survival within macrophages and for eukaryotic cell invasion.
MAP kinase-interacting serine/threonine-protein kinase 1 is an enzyme that in humans is encoded by the MKNK1 gene.
In molecular biology, LcrV is a protein found in Yersinia pestis and several other bacterial species. It forms part of the Yersinia pestis virulence protein factors that also includes all Yops, or Yersinia outer protein, but the name has been kept out of convention. LcrV's main function is not actually known, but it is essential for the production of other Yops.
Erythrogenic toxins, also referred to as streptococcal pyrogenic exotoxins, are secreted by strains of the bacterium Streptococcus pyogenes. SpeA and SpeC are superantigens, which induce inflammation by nonspecifically activating T cells and stimulating the production of inflammatory cytokines. SpeB, the most abundant streptococcal extracellular protein, is a cysteine protease. Pyrogenic exotoxins are implicated as the causative agent of scarlet fever and streptococcal toxic shock syndrome. There is no consensus on the exact number of pyrogenic exotoxins. Serotypes A-C are the most extensively studied and recognized by all sources, but others note up to thirteen distinct types, categorizing SpeF-M as additional superantigens.
In molecular biology, the haemolysin expression modulating protein family is a family of proteins. This family consists of haemolysin expression modulating protein (Hha) from Escherichia coli and its enterobacterial homologues, such as YmoA from Yersinia enterocolitica, and RmoA encoded on the R100 plasmid. These proteins act as modulators of bacterial gene expression. Members of this family act in conjunction with members of the H-NS family, participating in the thermoregulation of different virulence factors and in plasmid transfer. Hha, along with the chromatin-associated protein H-NS, is involved in the regulation of expression of the toxin alpha-haemolysin in response to osmolarity and temperature. YmoA modulates the expression of various virulence factors, such as Yop proteins and YadA adhesin, in response to temperature. RmoA is a plasmid R100 modulator involved in plasmid transfer. The HHA family of proteins display striking similarity to the oligomerisation domain of the H-NS proteins.
In molecular biology, YopH, N-terminal refers to an evolutionary conserved protein domain. This entry represents the N-terminal domain of YopH protein tyrosine phosphatase (PTP).
In molecular biology, the protein domain YopE refers to the secretion of virulence factors in Gram-negative bacteria involves transportation of the protein across two membranes to reach the cell exterior. It not only infects the host cell but also protects the bacteria. It undergoes several mechanisms to evade the hosts immune system. This particular protein domain can be referred to as a Rho GTPase-activating protein (GAP).
In molecular biology, YopR is a protein domain commonly found in gram negative bacteria, in particular Yersinia and is a core domain. Proteins in this entry are type III secretion system effectors. They are named differently in different species and in Yersinia has been designated YopR which is encoded by the YscH gene. This Yop protein is unusual in that it is released to the extracellular environment rather than injected directly into the target cell as are most Yop proteins. A hallmark of Yersinia type III machines is the presence of needles extending from the bacterial surface. Needles perform two functions, firstly, as a channel to export effectors into the immune cells and secondly as a sensor.
In molecular biology, YadA is a protein domain which is short for Yersinia adhesin A. These proteins have strong sequence and structural homology, particularly at their C-terminal end. The function is to promote their pathogenicity and virulence in host cells, though cell adhesion. YadA is found in three pathogenic species of Yersinia, Y. pestis,Y. pseudotuberculosis, and Y. enterocolitica. The YadA domain is encoded for by a virulence plasmid in Yersinia, which encodes a type-III secretion (T3S) system consisting of the Ysc injectisome and the Yop effectors.
RNA thermometers regulate gene expression in response to temperature allowing pathogens like Yersinia to switch on silent genes after entering the host organism. Usually, RNA thermometers are located in the 5'UTR, but an intergenic RNA thermometer was found in Yersinia pseudotuberculosis. The LcrFRNA thermometer together with the termo-labile YmoA protein activates synthesis of the most crucial virulence activator LcrF (VirF). The RNA thermosensor sequence is 100% identical in all human pathogenic Yersinia species.
|Wikispecies has information related to Yersinia pseudotuberculosis|