Explain the pathogenesis of Helicobacter pylori

Helicobacter pylori (H. pylori) is a Gram-negative, spiral-shaped bacterium that colonizes the human stomach. About 50% of the world’s population is believed to be infected with H. pylori. In areas where transmission is most prevalent, infection rates can soar to up to 90%. Although most hosts mount humoral and cellular immune responses against H. pylori, the absence of antimicrobial therapy has turned colonization into a decades-old problem.

This dilemma is not without serious consequences – people suffering from H.pylori infection have a higher risk of developing peptic ulcer disease, gastric adenocarcinoma and gastric lymphoma (Alouf and Popoff 468). H. pylori infection affects mainly the mucus-secreting antral-type gastric epithelium and the stomach fundus. The bacterium creates in these organs lesions known as type B or non-specific gastritis. Certain antimicrobial treatments are necessary to eliminate the infection and heal the lesions in the process. The lesions, however, will return should reinfection occur (Crocetti, Barone and Oski 263). H.

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pylori colonization likewise takes place when there is a presence of gastric-like tissue in the duodenum. The bacterium settles and multiplies in the said tissue, causing active inflammation that might eventually lead to the development of a duodenal ulcer. There is indeed a close link between H. pylori infection and duodenal ulcer. Patients with recurrent duodenal ulcers were found to have high levels of the bacterium in the margins of their ulcers and antral muscosas (Crocetti, Barone and Oski 263). Furthermore, studies show that adults suffering from H.

pylori infection are more at risk for gastric carcinoma. These inquiries noted the close association between H. pylori seropositivity and gastric cancer incidence and mortality. H. pylori colonization often precedes the occurrence of a low-grade mucosa-associated lymphoid tissue (MALT) lymphoma, a rare type of neoplasia. Early stages of MALT lymphoma can be cured by treating H. pylori infection with antibiotics (Crocetti, Barone and Oski 263). II. Explain how a host responds to Helicobacter pylori. The gastroduodenal tract is the body’s first line of defense against H. pylori infection.

This region, through t-cell dependent responses, has the ability to distinguish pathogenic bacteria from commensals. Despite this vigorous form of protection against H. pylori antigens, most infected subjects still fail to spontaneously eliminate the pathogen (Hayat 208). The bacterium uses a protein called SabA in order to stick itself to special sugars on stomach cells. With these sugars on its surface, the bacterium is mistakenly identified by the immune system as a part of the intestinal tract (Shetty, Paliyath, Pometto and Levin 164). Having managed to evade the immune system, the H.

pylori antigen then adheres itself even more closely to the stomach wall. In doing so, the bacterium gains better access to nutrients – it obtains the latter by creating leaks in the membranes of stomach cells. Furthermore, the bacterium’s level of protection is increased. The stomach’s natural mucus shedding will not be able to flush it out, thinking that it is one of its components (Sherwood 485). H. pylori infections in children are mostly asymptomatic. Moreover, childhood bouts of the colonization usually clear up by themselves (although children can experience reinfection).

In cases wherein the infection is symptomatic, the most common symptom is chronic and recurrent abdominal pain. Young infants, however, may also experience vomiting (Crocetti, Barone and Oski 263). H. pylori colonization in adults manifests itself primarily through severe abdominal pain, specifically between the breastbone and the belly button. Less common symptoms, meanwhile, include nausea and loss of appetite. One dangerous symptom of H. pylori infection in adults is anemia with weakness and fatigue. This is usually an indicator of bleeding ulcers (Edlin and Golanty 267).

III. Epidemiology of Helicobacter pylori Most patients acquire H. pylori infection during childhood. Because most childhood cases of the colonization are asymptomatic, there is the possibility that the symptoms appeared only during their adult years. H. pylori infection has three common transmission routes: fecal-oral, oral-oral and gastro-oral. The multiple means in which the disease can be transmitted has prompted experts to consider it as a “situational opportunist” (Schlossberg 969). Fecal-oral transmission, however, happens to be the most common.

People in most Third World countries acquire H. pylori infection by drinking water that has traces of contaminated fecal matter. Fecal-oral transmission is therefore also regarded as the most important because it paves the way for easy detection of the disease. Infected children and adults pass stools from which the H. pylori bacterium has been cultured (Schlossberg 969). Oral-oral transmission of the H. pylori bacterium, meanwhile, is very rampant in Africa. Mothers in this continent were found “(premasticating foods) given to their infants” (Schlossberg 969).

Gastro-oral transmission occurs through unsafe contact with gastric secretions such as vomit. As a result, H. pylori infection was common among gastroenterologists in previous decades – they performed endoscopies without gloves and or with instruments that were not properly disinfected (Schlossberg 969). The socio-economic profile that epidemiologists created for H. pylori infection patients revolved around practicing poor household hygiene. This was the commonality of all the known major risk factors behind H. pylori infection: a. Unsanitary birthing process in developing nations b. Low socioeconomic status

c. Crowded living conditions d. Large family size e. Unsanitary living conditions f. Unclean food or water g. Presence of infants in the home h. Exposure to gastric contents of infected individuals (Schlossberg 969) The number of cases of H. pylori infections, however, differs in terms of ethnic background, geographic location, age and socioeconomic standing. In Third World countries, 70% to 90% of the populations are infected with the H. pylori bacterium by age 20. In sharp contrast, the prevalence of the disease within the same age bracket in First World countries ranges from only 25% to 50%.

In the United States, for instance, there is only at most a 15% prevalence rate of H. pylori colonization among American-born middle-class whites and individuals whose parents were born in the US. On the other hand, the disease is prevalent among immigrants from Third World countries and the country’s marginalized sectors (Schlossberg 970). IV. Treatment and other strategies to reduce or prevent the disease. According to health experts, the best way to prevent H. pylori infection is to improve sanitation and household hygiene (Schlossberg 970).

First, regular and thorough hand washing must be practiced. Children and adults alike must make it a habit to wash their hands with soap and warm, clean water before eating and after using the toilet. Second, the sharing of dining utensils must be avoided. Because eating utensils and drinking glasses always come into contact with saliva, they are excellent carriers of disease-causing bacteria. Dining utensils must also be washed properly before and after usage. Afterwards, they must be kept in a clean storage area or container. Lastly, food and water contamination must be prevented.

Consumption of food and water that may have been exposed to sewage or floodwater must be avoided. When shopping, keep meat, seafood and produce in separate wrappings. Upon purchase, they must be immediately stored in the freezer. Paraphernalia used in preparing food (chopping board, knives, ladles, etc. ) must likewise be thoroughly washed in soap and clean, warm water. Meanwhile, there are several treatment regimens used in curing patients suffering from H. pylori infection. The infection is first confirmed by culture, serology or breath test. Afterwards, patients are usually put on two to three drugs for 14 to 21 days.

Treatment, however, is recommended only for symptomatic patients. Asymptomatic children or children with nonspecific gastrointestinal tract symptoms are prohibited from availing of the aforementioned treatment procedures (Crocetti, Barone and Oski 264). In the treatment of H. pylori colonization, the objective is total eradication of the bacterium. Otherwise, the pathogen may evolve into a tougher, more resistant strain – requiring the patient to undergo a longer and more expensive treatment regimen. The said goal explains the need for multidrug therapy in treating H. pylori infection.

Doctors usually prescribe for children a proton-pump inhibitor and two of the following drugs in various combinations: clarithromycin, metronidazole or amoxicillin. Tetracycline, meanwhile, is used on older children and adults (Crocetti, Barone and Oski 264). Medical researchers, however, continue to look for better ways of curing H. pylori infection. In 2006, scientists in Nice, France came up with two different rifabutin-based, triple-therapy approaches in treating drug-resistant strains of H. pylori. Indeed, drug resistance is a major problem in the treatment of H. pylori colonization.

Current drug regimens have been shown to fail in up to 27% of patients. This failure is often attributed to metronidazole or clarithromycin resistance – about 75% of H. pylori infections are resistant to both drugs (Wendling 7). The approaches were tested on patients with H. pylori infections who were resistant to both metronidazole and clarithromycin in two separate trials in Europe. In the first trial, 70 of the 86 subjects (81%) were successfully cured of their illness. Out of the 16 patients in whom the treatments were a failure, 5 exhibited post-treatment resistance to rifampicin.

Three, meanwhile, were resistant to ciprofloxacin (Wendling 7). In the second trial, 54 out of the 69 subjects (78%) achieved complete eradication of their ailment. Of those in whom the treatments failed, six had to prematurely discontinue treatment due to side effects. Eight subjects, meanwhile, were cured after switching to high-dose dual therapy (Wendling 7). V. Explain the social and or ethical issues that may relate to Peptic Ulcer Disease. One of the main ethical issues surrounding the treatment of peptic ulcer disease is the excessive focus that experts place on its biological aspect.

Critics point out that the vast amount of research on the connection between H. pylori infection and peptic ulcer disease resulted in the overlooking of other possible causes of peptic ulcer disease. Apart from the H. pylori bacterium, psychological disorders such as generalized anxiety disorder (GAD) and post-traumatic stress disorder (PTSD) can also lead to peptic ulcer disease. It is already an established medical fact that suppressed emotions, especially anger, manifest themselves through physical ailments.

Such a one-sided approach to treating peptic ulcer disease is very dangerous, as it might, for some patients, the alleviation of symptoms but not the disease itself (Harris 243). A patient might be subjected to potentially harmful antibiotics even if he or she does not really need them in the first place. Worse, he or she will have to needlessly endure several painful side effects. In the process, the patient ends up similar to a guinea pig. Too much focus on the biological causes of peptic ulcer disease has more chilling effects.

In their strong desire to come up with new antibiotics in a short span of time, medical researchers and pharmaceutical companies might dupe patients into participating in clinical trials through misinformation (Stirrat 163). In order to prove to the patients that they are “concerned” about their recovery, medical researchers and representatives would bombard them with sophisticated-sounding but very confusing scientific jargon. As a result, even patients who are suffering from milder forms of peptic ulcer disease would needlessly endanger their health by joining trials with uncertain results.

Connected to this effect is the sale of antibiotics that have either insufficient information or complete but misleading information (Verdu and Castello 608). Verdu and Castello (2004) argued that for a patient to be able to make an informed choice regarding specific treatment, his or her doctor must give detailed but understandable information such as those regarding side effects, recommended lifestyle changes and the consequences of non-compliance. In addition, the patient must also obtain complete but comprehensible information from the leaflets that come with the very drug that they are supposed to take.

But most doctors fail to properly inform their patients about the drugs that they are prescribing to them, while many drugs come with information leaflets filled with incomprehensible medical terminologies. Patients, therefore, have no other choice but to browse through websites that contain potentially erroneous information about drugs, illnesses and medical procedures (Verdu and Castello 608). Works Cited Alouf, Joseph E. , and Michel R. Popoff. The Comprehensive Sourcebook of Bacterial Protein Toxins. 3rd ed. Saint Louis: Academic Press, 2006. Crocetti, Michael, Michael A. Barone, and Frank A. Oski. Oski’s Essential Pediatrics.

2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2004. Edlin, Gordon, and Eric Golanty. Health and Wellness. 9th ed. Sudbury: Jones and Bartlett Publishers, 2006. Harris, John. “Scientific Research is a Moral Duty. ” Journal of Medical Ethics 2005: 31. JME. BMJ. com. 27 March 2009 <http://jme. bmj. com/cgi/content/full/31/4/242>. Hayat, M. A. Handbook of Immunohistochemistry and in situ Hybridization of Human Carcinomas: Molecular Pathology, Colorectal Carcinoma, and Prostate Carcinoma. Saint Louis: Academic Press, 2005. Schlossberg, David. Clinical Infectious Disease. Cambridge: Cambridge University Pres


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