Salmonella – description, pathogenesis, symptoms
Salmonella is a gram-negative bacillus that causes inflammation of the GI tract and in some cases, if the immune response is not sufficiently powerful and treatment is not administered, can become systemic and cause even more serious conditions throughout the body. After ingestion, these bacteria cause infection by invading the epithelial cells of the small intestine and macrophages. Though there are more than two thousand different subspecies of Salmonella, few of them are able to cause serious conditions in humans—for most, the disease resolves itself in a matter of days. Those who are most affected by Salmonella infection are infants, the elderly, and people with compromised immune systems. Some of the main conditions caused by Salmonella are gastroenteritis, enteric fever, and bacteremia, while the general symptoms of salmonella include vomiting, nausea, diarrhea, and abdominal pain. While there are typically few to no long-term effects as a result of a Salmonella infection, more serious complications may arise.
The mention of the latest salmonella outbreak is often enough to make anyone’s stomach turn—people in the US and other countries have long maintained a strong aversion to, and even anxiety towards, the very idea of salmonella entering the food supply. It is this fear that drives the government and the agricultural industry, which are also prey to the overwhelming dread of the salmonella contamination, to take extreme measures to prevent the slightest risk of salmonella contamination and that continually puts the public on edge—but despite this widespread apprehension, much of the public remains ignorant of what salmonella really is. For many, it is but an ominous name, nothing more than an impending threat held at bay on by the powers of modern technology. Little is known about salmonella’s growing resistance, what it causes, or how it actually affects the body. A bacterial disease of growing importance to the populace,
salmonella is a specialized invader of the gastrointestinal system that can cause a variety of painful conditions of varying severity.
The bacteria known as Salmonellae are gram-negative, rod-shaped bacilli that belong to the family Enterobacteriacea—they are typically anaerobic, unable to form spores, and motile, or able to move around spontaneously. An important characteristic of the Salmonella bacteria is that they are able to grow and multiply outside living host organisms, thus having greater survival chances than otherwise (Gray and Fedorka-Cray 56).
The bacteria can have a combination of three antigens: the O antigen, H antigen, and Vi antigen. The O antigen is located in the cell wall of the bacterium, and each salmonella bacillus may posses 2 or more O antigens on its surface. Also, the H antigen is a flagellar antigen that can be destroyed by heat and enables the motility of the Salmonella bacterium (Slack and Snyder 295). The last antigen is known as...