Open access peer-reviewed chapter
By Isidro Favian Bayas-Morejón, Rosa Angélica Tigre-León, Edison Riveliño Ramón-Curay and Darwin Alberto Núñez-Torres
Submitted: March 25th 2019Reviewed: May 11th 2019Published: June 25th 2019
DOI: 10.5772/intechopen.86789
Downloaded: 316
Helicobacter pylori is considered a pathogen of global interest because it is a microorganism of very easy contagion between the hosts or host. Helicobacter pylori infection is now recognized as a problem that causes chronic gastritis, peptic ulcer disease, and lymphoproliferative disorders and is a major risk factor for gastric cancer. The diagnostic methods to detect H. pylori are classified such as direct or invasive, when the identification is directly, the bacterium obtained from gastric mucosa biopsy by endoscopy histology with various staining, culture and PCR techniques, while indirect or noninvasive or serological tests such as the breath test with urea marked with 13C.
The number of infected by
According to studies conducted, many of the pathogenic species of
The different methods used for diagnosis range from antigenic screening (Ag) to molecular techniques. Antigenic screening techniques have been associated with a high sensitivity of a detection limit of the
The bacterium is one of the most important findings for gastroenterologists, who for years sought answers to multiple intestinal problems. This is how the gastroenterologist Walery Jaworski in 1899 after analyzing samples of human gastric expirations isolated spiral elongated bacteria and called them
So, it took 79 years for the bacteria to be rediscovered by the Australian doctors Barry Marshall and Robin Warren, who managed to make the first isolation through a pure culture in 1979. This rediscovery allowed them to be Nobel Laureates in 2005 [15].
Taxonomically, we can describe
The multiple genotypic and phenotypic characteristics are different from those of
Although in general there is no difference between the sexes, in some developed countries, there is a higher prevalence of infection in men than in women [16].
The prevalence of
Epidemiological and microbiological evidences have several transmission routes that have been proposed in the studies carried out. The gastro-oral, oral-oral, and fecal-oral routes are the most important routes of transmission [12]. Other routes of importance are also breastfeeding and iatrogenic transmission which are also included as alternating forms for the transmission of the pathogen. The possibilities of spreading the pathogen are of three possible vectors that have been suggested to maintain the viable form of the bacteria: water, food, and animals.
The prevalence of
Through molecular methods,
In another study, developed by Moreno et al. [21]; Moreno and Ferrús, [22]
On the other hand,
Those foods that have a water activity (aw) >0.97 and a pH between 4.9 and 6.0 theoretically provide the ideal conditions for the survival and development of
Vegetables are one of the foods with the highest risk of fecal contamination, since they are in contact with soil and contaminated irrigation water, which would mean the spread of
On the other hand, the ability of
Milk could also act as a vehicle for
On the other hand, Meng et al. [36] analyzed 11 raw chickens and 18 samples of tuna meat ready for consumption (sushi).
Studies have also been conducted on the presence of
The presence of
The term gastritis should be reserved for the histologically demonstrated inflammation of the gastric mucosa. Gastritis is not the mucosal erythema seen during endoscopy, nor is it interchangeable with the term “dyspepsia” [13]. On the other hand, the different etiological factors that cause gastritis are multiple and heterogeneous; to gastritis it has been classified with a chronological base (acute or chronic), such as histological typologies, anatomical distribution or its pathogenic mechanism, clinical correlation, histological data, abdominal pain or dyspepsia, and endoscopic data in gastric mucosal investigation [13].
The pathogenesis of chronic gastritis by
Second stage of the inflammatory process of the gastric mucosa by
It is the uncontrolled growth of stomach cells. Malignant tumors can originate in each of the three layers: mucosa, muscle, and serosa. This is also known as gastric cancer that originates in the stomach [41]. The risk factor is considered any caused that increases the likelihood of having a disease such as cancer, even though several risk components do not mean that the person will have the disease; Some scientists connoted that the risks that take a person to be more prone to suffer stomach cancer are several such as:
Incidence according to sex: Stomach cancer is more common in men than in women [16].
Age: The rate of stomach cancer in people over 50 years increases sharply [42].
Ethnic origin: In the United States, stomach cancer is more common among Americans of Hispanic origin, black people, and Asians and islanders compared to white people who are not of Hispanic origin [41].
Geography: On a global scale, stomach cancer is more common in Japan, China, Eastern and Southern Europe, as well as Central and South America [41].
Several risk factors for gastric cancer have been described, which play a fundamental role in their genesis, some of them remain under discussion, and others, on the contrary, have been confirmed more and more clearly [43].
Within the genetic risk factors [41], we have:
Families of patients with gastric cancer: incidence 2–3 times higher
Blood group A.
Among the environmental risk factors [41], we have:
Food (variable in each country): dried and salted fish, very spicy foods, and red meats, among others
Ingestion of alcohol, hot drinks, and sodium nitrate; chewed tobacco
Radiation.
Within the premalignant risk factors [41], we have:
Atrophic gastritis, intestinal metaplasm, and dysplasia.
Pernicious anemia (20 times more frequent than in normal subjects).
Gastric polyps: multiple hyperplasia, greater than 2 cm with some degree of dysplasia 0.4–4% of association with gastric cancer [41].
People who have suffered from a certain type of stomach lymphoma, known as lymphoma of lymphatic tissue associated with the mucosa (MALT), have an increased risk of developing adenocarcinoma of the stomach, probably due to infection with
The gastric infection produced by
Entrance and lodging of
The diagnostic methods of
The other indirect methods are based on the detection of certain characteristics of the bacteria, such as the ability to hydrolyze through urea, and based on the breath test or the response of the immune system through the measurement of specific antibodies. Its primary advantage is its noninvasive nature [44].
The presence of the germ can be recognized with the usual hematoxylin and eosin stain, although it is more easily demonstrated with other stains such as Giemsa. The histology not only demonstrates the presence of the microorganism but also informs about the morphological changes of the gastric mucosa [44].
Under optimal conditions
The selection and inoculation of the bacteria depend on the number and types of tests to be carried out as well as on the factors, type of bacteria, clinical importance of the isolation, availability of the strain, and reliable method of verification [46]. Plate culture has advantages ranging from typifying the organism to determining its sensitivity to antibacterial agents, so it is important to study it from the epidemiological point of view, because it allows knowing the pattern of resistance to different therapeutic regimens with a specificity of the 100% and a lower sensitivity than other diagnostic techniques [3]. This microorganism is also urease, oxidase, and catalase positive, characteristics that are frequently used in the identification of the microorganism, although its isolation is relatively complex [16].
It is usually considered a difficult and tedious technique. However, adopting a series of minimal precautions, most laboratories achieve the growth of the microorganism [44].
Serological techniques only indicate a previous exposure to the microorganism but do not discriminate between people with active infection and disease in healthy individuals with prior exposure to infection [44]. Rapid tests are methods for the detection of antigens and antibodies in serum, plasma, whole blood, and other fluids, which give results in a few minutes [47]. These serological techniques are widely used today for rapid diagnosis in laboratories.
The enzyme-linked immunosorbent assay (ELISA) is widely used to perform epidemiological studies on a considerable number of individuals [48].
In a work done by Siavoshi et al. [49], for the intracellular detection of
This is a chromatographic immunoassay for the qualitative detection of
Molecular methods are the names given to all the laboratory techniques used to isolate DNA or extract it in high purity, visualize it to see its state, cut it and paste it (Iglesias [51]), or amplify a region in a huge amount of molecules: fragment cloning in bacteria or other vectors such as viruses as well as polymerase chain reaction (PCR).
Infectious diseases have become the “spearhead” for the development of molecular diagnostic tests, with more than 50% of the techniques available today. The main explanation for this development is due to the difficulty of detecting a pathogen through classical microbiology [52] (Table 1).
| Methods | Characteristic | Advantage | Disadvantages |
|---|---|---|---|
| Histological techniques | Habitual staining of hematoxylin and eosin Giemsa stain | Demonstrates the presence of the microorganism and reports on changes in the mucosa | The technique requires samples obtained from a biopsy Proper selection of stain fixatives |
| Culture | Cultivation of the microorganism in specific media under microaerobic conditions The optimum temperature of culture is from 35 to 37°C [53] | Isolate the microorganism to study its behavior (in vitro) | It is difficult to isolate, since Samples destined for culture remain viable for approximately 5 hours and when stored in saline at 4°C or for more than 24 hours if stored at 4°C in a transport medium specific for Another disadvantage is the high contamination of the environment with accompanying biota, which makes it difficult to isolate |
| Serological techniques | Methods for the detection of antigens and antibodies (serum, plasma, and whole blood, among others) Enzyme-linked immunosorbent assay (ELISA) | Rapid laboratory tests | It can induce a false-negative result |
| Antigenic screening | Chromatographic immunoassay for the detection of | Rapid laboratory tests | Possible false positives due to cross reactions with other organisms [56] |
| Molecular Methods | DNA amplification of the pathogen | Great versatility as an analysis technique, sequences are amplified from minute amounts of target DNA, even from DNA contained in a single cell | Need to have information on the target DNA sequence Short size of the PCR products The ease with which DNA is amplified requires avoiding the danger of contamination inherent to the multiplier power of the reaction |
Comparison of diagnostic methods for
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