Research Paper Helicobacter Pylori

Topics: Helicobacter pylori, Stomach, Peptic ulcer Pages: 9 (2479 words) Published: April 17, 2013
Helicobacter pylori|
Previously named Campylobacter pyloridis, is a Gram-negative, microaerophilic bacterium found in the stomach. | |
Microbiology (B1325) Research Paper|

Detailed Introduction

Helicobacter pylori are a species of epsilon proteobacteria which colonizes the harsh environment of the human stomach. Its name refers to both its spiral shape (Helicobacter) and the area of the lower stomach which it habitually colonizes: the gateway (pylorus) between the stomach and small intestine (Meyers, 2007). This bacterium is thought to be present within up to 50% of the human population and has been linked to the development of a number of different medical conditions (Chalmers et al. 2004). This report will provide information about the discovery of H. pylori as well as its morphological characteristics, taxonomic information, biochemical/metabolic characteristics, chemotherapeutic methods of control/treatment/eradication, immunological responses, pathological information, and epidemiology information.

Morphological Characteristics

Helicobacter pylori are a spiral-shaped, Gram-negative rod approximately 0.5 x 3.0 micrometers in size. It is catalase-positive organism which has 4-6 sheathed flagella attached to one pole which allow for motility. It lives in the human stomach and duodenum. H. pylori possess five major outer membrane protein (OMP) families. The largest family includes known and putative adhesions. The other four families include porins, iron transporters, flagellum-associated proteins and proteins of unknown function. Like other typical Gram-negative bacteria, the outer membrane of H. pylori consists of phospholipids and lipopolysaccharide (LPS). The O antigen of LPS may be fucosylated and mimic Lewis blood group antigens found on the gastric epithelium. The outer membrane also contains cholesterol glucosides, which are found in few other bacteria. H. pylori has four to six lophotrichous flagella; all gastric and enterohepatic Helicobacter species are highly motile due to flagella. The characteristic sheathed flagella filaments of Helicobacter are composed of two copolymerized flagellants, FlaA and FlaB. [1](From Wikipedia, the free encyclopedia).

Taxonomic Information

Helicobacter pylori are a gram-negative, spiral-shaped organism associated with gastrointestinal disease in humans. It has a worldwide prevalence, with approximately 50% of the world's population infected. Before the first isolation and documentation of this organism from the human stomach in 1982, it was assumed that the human stomach was a sterile environment because of the high levels of acid, which would exclude it as an ecologic niche for any organism. This bacterium is the human-adapted Helicobacter primarily found in the gastric mucosa and areas of gastric metaplasia in the duodenum and occasionally in Meckel's diverticulum and the rectum. It has been cultured rarely from feces, blood, and saliva. It can be detected by polymerase chain reaction (PCR) in dental plaque and feces. In the latter instances, the viability of the bacteria is in question. H. pylori also have been found in nonhuman primates and cats. H. pylori detection in animals is not common and could be due to human contact with animals. To date, no environmental reservoir has been shown. [2](

Biochemical/Metabolic Characteristics

The genus Helicobacter was created in 1989 with H. pylori as the type species. Since then the genus has expanded to include about 18 species. Some species were reclassified from Campylobacter, but most were newly discovered microorganisms from gastric or intestinal sites in mammalian host animals. The essential property of almost all helicobacter is the presence of sheathed flagella. Most species possess strong ureolytic ability, particularly those associated with gastric mucosa, and exhibit considerable diversity in cell morphology with...
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