What are the pathogenic bacteria in the intestine?

Bacteria can be divided into beneficial and harmful types, which are known as probiotics and pathogenic bacteria, respectively. The intestinal tract is easily affected by factors such as diet and hygiene, leading to the invasion of some bacteria and damaging the health of the intestinal tract. Common intestinal pathogenic bacteria include Escherichia coli and Salmonella.

1. Escherichia coli

Escherichia coli is one of the most famous bacteria in the intestines of humans and animals, mainly parasitizing in the large intestine and accounting for approximately 1% of the intestinal bacteria. It is a gram-negative short rod bacterium with blunt ends, capable of motility and without spores. Escherichia coli can synthesize vitamins B and K, and is not pathogenic under normal conditions. However, if it enters the gallbladder, bladder, or other locations, it can cause inflammation. Its detection in water and food can be considered as an indicator of fecal contamination. The number of Escherichia coli colonies is often used as a hygienic standard for drinking water, food, or drugs.

2. Salmonella

Salmonella is the pathogen of salmonellosis, belonging to the Enterobacteriaceae family and gram-negative intestinal bacilli. Nearly one thousand species (or strains) have been discovered. Based on their antigenic components, they can be divided into basic groups such as Salmonella A, B, C, D, and E. Among them, the Salmonella species that are mainly associated with human diseases include Salmonella paratyphi A, Salmonella paratyphi B, Salmonella typhimurium, Salmonella choleraesuis, Salmonella typhi, and Salmonella enteritis. While Salmonella typhi, Salmonella paratyphi A, and Salmonella paratyphi B can cause human diseases, most other Salmonella species can only cause diseases in livestock, rodents, birds, and other animals, but they can sometimes contaminate human food and cause food poisoning.

1. Obesity

Obesity may be triggered by bacterial infection rather than excessive eating, lack of exercise, or genetic factors, which may have far-reaching implications for public health systems, the pharmaceutical industry, and the food manufacturing industry. If obesity is caused by bacteria, it may be contagious and may originate from unknown environmental factors or be transmitted from parents.

2. Autoimmunity

When young female mice are exposed to normal intestinal microorganisms from adult males, their testosterone levels increase. Scientists have subsequently confirmed that this hormone is crucial for the prevention and treatment of intestinal microbial diseases. It has been discovered that the gender of animals determines their intestinal microbial composition, and these microorganisms affect sex hormone levels, which in turn regulate immune-mediated diseases.

3. Blood Pressure Regulation

Reducing the intestinal microbiota biomass of Olfr78 knockout mice through antibiotic administration resulted in increased blood pressure, suggesting that propionic acid produced by the intestinal microbiota regulates blood pressure through the Olfr78 receptor.