Bacilli are also called Rod bacteria designated. The bacilli include bacteria such as Escherichia coli or salmonella.
What are bacilli?
Bacilli are rod-shaped bacteria. The term does not encompass a specific group of bacteria, but only refers to the appearance of the bacteria. There are many different types of bacteria among the bacilli.
This includes both gram-positive and gram-negative bacteria. Gram-positive bacteria can be stained blue using the so-called Gram stain. Gram-negative bacteria turn red. While the gram-positive bacteria also have an outer cell membrane in addition to a thick peptidoglycan layer made of murein, the gram-negative bacilli lack this additional cell wall. The distinction between gram-positive and gram-negative bacilli plays a role in the treatment of infectious diseases. Gram-positive bacilli are fought with different antibiotics than gram-negative bacteria.
In contrast to the cocci, the bacilli usually live alone. The gram-positive bacilli include Bacillus, Lactobacillus, Corynebacterium, Listeria or Propionibacteria. Gram-negative bacilli are, for example, Salmonella, Escherichia, Pseudomonas and Bacteroides.
Occurrence, Distribution & Properties
The spread of the rod bacteria is very different depending on the species. Bacteria like Escherichia or Lactobacillus live physiologically in the human intestine. They are part of the healthy intestinal flora and take on various tasks in digestion. Clostridia also live in small quantities in the human intestine. If the local flora is damaged by antibiotic therapy, for example, the Clostridium bacterium spreads and causes severe inflammation. Humans are also the only reservoir for the rod bacterium Corynebacterium diphtheriae. The diphtheria pathogen is transmitted through close contact with infected people.
On the other hand, some salmonella species are found mainly on eggs and in poultry meat. Other types of salmonella, such as Salmonella typhi, on the other hand, are preferably transmitted by people who are already sick. Ingestion is also possible through contaminated animal food.
Meaning & function
Some bacilli live in a symbiosis with humans. These include, for example, the lactobacilli. They belong to the order of lactic acid bacteria and occur naturally in humans in the intestine and vagina. Lactobacilli convert lactose into lactic acid. They belong to the group of probiotic bacteria. This means that they worsen the living conditions of pathogenic microorganisms with their metabolic products. They ensure an acidic environment. Most bacteria, which are harmful to humans, prefer an alkaline environment. Lactobacilli prevent pathogenic germs from settling in the vagina and intestines. In the gastrointestinal tract, the bacilli produce various nutrients. These include, for example, niacin and folic acid.
Escherichia coli is also a rod bacterium that belongs to the physiological intestinal flora of humans. As part of the local flora, it protects the intestinal mucosa from the colonization of harmful bacteria. In addition, the coli bacteria convert various nutrients, which then serve to nourish the intestinal mucous membrane cells. Escherichia coli bacteria also act as producers of vitamin K.
Just like lactobacilli and Escherichia coli, the Bacteroides also belong to the normal flora of the mucous membranes in the gastrointestinal tract. The exact tasks of the bacteria are still unclear. What is certain, however, is that they act as placeholders. They settle on the intestinal mucosa and thus prevent pathogenic microorganisms from spreading in the intestine.
Illnesses & ailments
Some of the bacilli are pathogenic to humans. This includes, for example, the Corynebacterium diphteriae. It is the causative agent of diphtheria. Diphtheria toxin is responsible for the sometimes severe symptoms of the disease. It enters the bacterium via the virus Prophagen beta. This leads to fatigue, nausea and vomiting in almond and pharyngeal diphtheria. A yellowish-white coating forms on the almonds, which is accompanied by a putrid, sweetish halitosis. Laryngeal diphtheria is dangerous, with a barking cough, hoarseness and, in severe cases, attacks of suffocation.
Listeria can also cause an infectious disease. Listeriosis is caused by the bacterium Listeria monocytogenes. The clinical picture of listeriosis is variable. In immunocompetent individuals, the infection is usually symptom-free or with mild flu-like symptoms. Immunocompromised people can develop meningoencephalitis, peritonitis, or pneumonia. Listeria infection is also associated with risks in pregnant women. The infection can spread to the unborn child and cause an abortion.
In the clostridia group of bacilli there are several species that can harm humans. This includes Clostridium botulinum, the causative agent of botulism. Botulism is also known as meat poisoning. It is life-threatening poisoning caused by the botulinum toxin of the clostridia. The poisoning is usually caused by spoiled meat or cooked vegetables. The botulinum toxin affects the functioning of the nerves. Patients have blurred and / or double vision, dilated pupils, and difficulty speaking and swallowing. In severe cases, the paralysis spreads throughout the body, eventually leading to death from suffocation or cardiac arrest.
Another rod bacterium from the Clostridia family is Clostridium difficile. Clostridium difficile is one of the most common nosocomial pathogens. In healthy people, the bacterium is a harmless intestinal inhabitant. However, if the competing species of the physiological intestinal flora are pushed back by the administration of antibiotics, Clostridium difficile can multiply and produce toxins. These can cause pseudomembranous colitis, a life-threatening diarrheal disease.
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