SALMONELLA AND HOW IT WORKS IN THE HUMAN BODY
Introduction
Salmonella is a bacterium belonging to the Enterobacteriaceae family that behaves as a facultative intracellular pathogen, that is, that the pathogen can move and reproduce within the body quickly, it constitutes an important group of pathogens for animals and humans. It splits up in two species: S. enterica and S. bongori, of which S. enterica represents the most pathogenic species. (Figueroa and Verdugo, 2005).
It generally affects the intestinal tract and occasionally, the bloodstream, as it is one of the most common causes of gastroenteritis. Most cases occur during the summer months and in specific cases, epidemic outbreaks can occur. (Figueroa and Verdugo, 2005).
The following text aims to present the various chemical phenomena that occur within the body when coming into contact with salmonella.
Development.
The main entry of salmonella to human being is orally due to contact with infected animal feces, contaminated food and water. When the bacterium enters the subject orally, it experiences many environmental changes, such as: acidic pH, increased temperature, low oxygen tension and high osmolarity, and it responds to these changes by modulating the expression of its genes. (Figueroa and Verdugo, 2005).
In the event of airway entry, an invasion occurs in the tonsils and lungs. (Figueroa and Verdugo, 2005).
People more frequently contract Salmonella, which, depending on its species, inoculum size, virulence factors expressed by the strain, the person involved and their immune status, will determine if the person will have a medium or severe infection or if it could even be at stake the life of this. (Figueroa and Verdugo, 2005).
Its habitat is the gastrointestinal tract of mankind. It is associated with:
Gastrointestinal disorders. (Figueroa and Verdugo, 2005).
Septicemic problems, a life-threatening problem, occurs when the body's response to salmonella causes damage to its own tissues. (Figueroa and Verdugo, 2005).
Abortion thanks to its capacity for cell invasion and survival. (Figueroa and Verdugo, 2005).
Salmonella Infection
Salmonella has the ability to resist the pH of the stomach, bile salts and peristalsis, which is a contraction process that occurs in the intestine, so “it is able to colonize the small intestine and invades the mesenteric lymph nodes, causing an infection” (Figueroa and Verdugo, 2005).
Salmonella evades the defenses of intestinal cells as these should act by destroying it, however, they begin to divide within phagocytes that are located in that area. Phagocytes are a type of immune cell that eliminate and surround microorganisms, also they eliminate dead cells, “this is why salmonella acts by dividing within these, so that they do not carry out such a process” (Figueroa and Verdugo, 2005).
This pathogen has five islands of pathogenicity, (these islands determine the ability of the microorganism to cause damage to the organism in which it lives). The islands of pathogenicity are those DNA replications that determine the degree of virulence that a microorganism can have, “thanks to its correct coordination is how they manage to adapt to the various changes that happen during the infection process” (Alfaro, 2018).
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| Proceso celular |
The best description of the phenomena that occur after the ingestion of the pathogen is described through the pathogenesis model based on the behavior of S. typhimurium when infecting a mouse:
Invasion
Where adhesion to ileal epithelial cells and M cells occurs, this allows transepithelial migration to reach the site of phagocytes.
After this, phagocytosis is induced by both professional and non-professional phagocytes, this is achieved through the expression of the islands of pathogenicity of Salmonella. (Alfaro, 2018)
Spread of the pathogen
It is possible for Salmonella to enter blood vessels, which allows it to be distributed in the blood, from where it can reach the bone marrow, liver or spleen; furthermore, “it can remain chronically in the cells of the phagocytic mononuclear system for up to a year, after the primary infection” (Alfaro, 2018).
Inflammation.
Neutrophils play an important role in both the inflammatory process and diarrhea. Infected cells produce cytokines that attract polymorphonuclear cells (PMN) that release prostaglandins capable of raising cAMP levels, these produce as a final effect an interruption of Na+ absorption and increased Cl- secretion, and “this leads to a loss of water from the cell” (Alfaro, 2018).
The enteropathogenesis caused by the diarrhea that is manifested is attributed to the expression of the SipA and SipC proteins, which appear while the pathogen is found in M cells and in enterocytes, which occurs 15 minutes after inoculation; “this phenomenon precipitates the onset of the inflammatory process” (Alfaro, 2018).
Conclusion.
Salmonella is a microorganism, which has a complex cellular process within the human body, that will depend on how resistant the immune system of each person is, the way in which the cells have their own development, and the degree of danger for each person, as it can be not so risky, high, just as the person’s life could be at sake, because of being a pathogen with the capacities it has to reproduce, adapt and develop with great ease.
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