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Helicobacter pylori flashcards
Helicobacter pylori flashcards
Helicobacter pylori flashcards
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Helicobacter pylori is a pathogen that thrives in an individual’s stomach. It is spiral in shape and is classified as a unipolar, microaerophilic, gram-negative bacterium. This bacterium was discovered to be the cause of more than eighty percent of all peptic ulcers2. H. Pylori have four to six flagella that help with its motility1. Its flagella also enable it to move into and take up residence in the thick mucus layer of the stomach3. This part of the stomach protects the bacterium from highly acidic contents. H. pylori’s genome was found to be one-third the size of E-coli’s genome2. This indicates that there are possibly many specializations or variation involved with H. pylori.
It is characterized that this organism produces the enzymes catalase and urease. Both catalase and urease helps with the bacterium’s pathogenicity. Urease enzyme is considered the main virulence factor of H. pylori. It breaks down urea, which then produces ammonia that protects the bacterium from the acid in the stomach3. Ammonia presents as a buffer that neutralizes stomach acid, helping H. pylori to thrive2. As well, catalase enhances its ability to overcome the white blood cells that tries to kill the bacteria1. H. pylori produces two more enzymes right after it colonizes the stomach. Protease and phospholipase are enzymes that act on gastric epithelium to destroy the mucus layer of the stomach1. Surrounding H. pylori, there is a structure called adhesins that enable it to bind to the host cell. H. pylori’s adhesins are also virulent factors since its adherence to the gastric mucosa protects it from the acidic pH. The most notable adhesin of this bacterium is a protein called “BabA” or blood group antigen binding adhesion2. When BabA bind to gastr...
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...cobacter pylori: microbiology, transmission and health significance. Gastrointestinal Nursing [serial on the Internet]. (2012, Feb), [cited March 23, 2014]; 10(1): 45-50. Available from: CINAHL Plus with Full Text.
2. Sherwood L, Kell R, Ward C. Human Physiology: From Cells to Systems. 2nd Canadian Edition. Ontario: Nelson Education Ltd; 2013. P. 609.
3. Kalali B, Mejias-Luque R, Javaheri A, Gerhard M. H. pylori Virulence Factors: Influence on Immune System and Pathology. Vol. 2014 (2014). Retrieved from: http://www.hindawi.com.login.ezproxy.library.ualberta.ca/journals/mi/2014/426309/cta/
4. Israel D, Peek R. The Role of Persistence in Helicobacter pylori pathogenesis. 2006;22(1):3-7.
5. Centers for Disease Control and Prevention. Helicobacter pylori [document on the internet]. July 1998. Available from: http://www.cdc.gov/ulcer/files/hpfacts.pdf
In the article, “An Endangered Species in the Stomach” by Martin J. Blaser, he talks about a 60,000 year old bacterium living in the human stomach, named “Helicobacter pylori”. H. pylori was first isolated for investigation in 1982 by Barry J. Marshall and J. Robin Warren. Later researchers discovered that H. pylori was responsible for developing peptic ulcers, breaks in the lining of the stomach, or could also cause stomach cancer. For the past 100 years, there has been decrease in H. pylori bacteria in humans due to the widespread use of antibiotics and improved hygiene. At the same time, the disappearance of H. pylori caused an unexpected rise in the acid reflux disease and a deadly type of esophageal cancer. Making H pylori a vital microorganism to research in order to expand the study of microbiology and its interaction with humans.
C. difficile is highly contagious and is transmitted through the fecal-oral route. 2 It also known to develop right afte...
Streptococcus pyogenes is thought to live benignly within one in five people, and is thusly one of the most common pathogens among humans. Due to its common
S. flexneri causes infection via bacterial penetration of the mucous membrane in the human colon. Humans are the only known reservoir to this pathogen (7). Following invasion of M cells and upon contact with the epithelial cells of the colon, S. flexneri releases Ipa proteins through a type three secretion system. Once inside the host cell, Ipa proteins activate small GTPases in the Rho family as well as c-src, a protooncogene, leading to cytoskeletal rearrangements. This alteration to the cytoskeleton allows the bacteria to be macropinocytosed by the host cell. Once inside the host, the pathogen colonizes the cytoplasm. IcsA, a bacterial surface protein, activates the host protein N-WASP and, in turn, stimulates actin assembly by host Arp 2/3. Thus, S. flexneri develops actin-based motility enabling the pathogen to become efficient at cell-to-cell spread and host cell cytoplasmic colonization. Infected cells become highly proinflammatory and secrete IL-8. IL-8 attracts neutrophils to the site of infection. The influx of neutrophils, chemokines and cytokines to the area damages the epithelial layer permeability and, in turn, advocates further S. flexneri invasion (6). Once initial invasion of S. flexneri occurs, the targeted epithelial cells require 45 minutes to 4 hours to mount an inflammatory response (8).
The Campylobacter species observed in 1886 from Theodor Escherich in the colonic mucus of infants who had died of “cholera infantum,” but they could not be cultured. (Miliotis & Bier 2003) Mc Fadyean and Stockman in 1909 first isolated Campylobacter fetus from aborted sheep fetuses. (Miliotis & Bier 2003) After that observed that the Campylobacter which called (Vibrio fetusovid), caused septic abortion in cattle. (Miliotis & Bier 2003) This pathogen bacterium starts to create problems dysentery in the cattle.( Miliotis & Bier 2003) In 1957 the King examined people which have bloody diarrhea the reason for the disease is the Campylobacter species. (Miliotis & Bier 2003)The species of Campylobacter are Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter fetus. (Miliotis & Bier 2003) The campyloCbacter is Gram-negative thin; (Siegrist 2014) Gram-negative bacteria are bacteria that do not retain the crystal violet dye in the Gram stain protocol. (Miliotis & Bier 2003) Gram-negative bacteria will thus appear red or pink following a Gram stain procedure due to the effects of the counter stain. (Miliotis & Bier 2003) The shape has the Campylobacter is curved and motile rod like S or spiral. (Siegrist 2014) Finally the Campylobacter has single polar flagella at one or both ends and they exhibit a rapid darting motion (Siegrist 2014), like picture1.
Aziz, Q. Q., Doré, J. J., Emmanuel, A. A., et al. (2013). Gut microbiota and gastrointestinal health: current concepts and future directions. Neurogastroenterology & Motility, 25(1), 4-15.
For many years, stomach was thought to be sterile due to its high acidic secretions in the gastric juice(#73) that’s why physicians previously attributed ulcers to stress or anxiety
With the earliest recordings coming from the Fifth Century B.C., streptococcus pyogenes, and more frequently, its symptoms have been prevalent among doctors and historians for hundreds of years. The first mentioning of streptococcus pyogenes is to be credited to Hippocrates, in which he describes the relative symptoms of the flesh-eating bacteria in its early stages. Then depicted by Billroth in 1874, patients carrying erysipelas were determined to have this certain bacterial infection. In 1883, the chain-forming bacteria were isolated by Fehleisen; and in the following year, Rosenbach applied the S. pyogenes name. Further advances in hemolytic and non-hemolytic studies were made by Lancefield in the 1930’s, in which the alpha, beta, and gamma subgroups of the hemolytic structures – detailed and defined by Schottmueller and Brown - were divided into serotypes.
Being a gram-negative bacterium, L. pneumophila has lipopolysaccharides (LPS) that act as endotoxin within a human host. The presence of a flagella is thought to mediate adherence to human lung cells, thereby causing infection, since flagella-less strains do not cause disease. Once attached to human cells, the organism is engulfed by a macrophage where is utilizes the internal environment to multiply.
“Salmonella Questions and Answers.” USDA Food Safety and Inspection Service. 20 Sept. 2006. 20 July 2008 .
E. Coli 0157, written by Mary Heersink, is a nerve-racking, adrenaline-filled story of a mother's experience with a then unknown deadly bacteria. The book brings up many reactions in its readers, especially the questioning of the practice of doctors in hospitals. The reader's knowledge base of scientific procedures in emergency centers was widened as well as the knowledge of how to the human body reacts to different agents in its system.
Due to their direct contact with patients, personnel of health care teams are exposed to a higher risk of contracting diseases. Specifically, this risk becomes more potential for dental professional teams if we know that most of the human microbial pathogens are isolated from oral secretions. They can cause serious diseases that might transmit from patients to the personnel, and vice versa (Bednarsh & Molinri, 2010). In 1970 and the early 1980s, result showed the tendency among dental professionals to have more certain infectious diseases than the general public due to their exposure to blood and saliva of their patients (Bednarsh & Molinri, 2010). Disease, such as hepatiti...
The stomach naturally produces acid, which is mainly responsible for food digestion and the destruction of any foreign pathogen or bacteria ingested with food. Acid is secreted by stimulating the partial
The most commonly recognized food borne infections are those caused by the bacteria Campylobacter, Salmonella, and E. coli 0157:H7, and by a group of viruses called Calicivirus, also know as the Norwalk viruses. “Thousands of types of bacteria are naturally present in our environment, but not all bacteria cause disease in humans.” (Schmutz 1)