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Anonymous users2024-02-06Mode of transmission of E. coli.
1. Spread through food.
2. It spreads through water.
3. Close contact transmission.
Enterohaemorrhagic E. coli infection is a zoonotic disease. The disease can be transmitted by patients with enterohaemorrhagic E. coli infection, carriers and domestic animals and poultry.
It can be contracted by drinking contaminated water or eating undercooked food, especially beef without treatment, hamburger steak and roast beef. Cases of infection from drinking or consuming unpasteurised milk, cheese, vegetables, fruit juices and yoghurt have also been detected.
Sick or infected animals are often the source of contamination of animal food. Infected animals can also contaminate local food, pastures, water sources or other water bodies and places through their excreted feces within their activity range, causing cross-contamination and infection, which is extremely harmful.
Characteristics of E. coli.
1. Escherichia coli is a bacterium and belongs to prokaryotes.
Has a cell wall consisting of peptidoglycan and contains only ribosomes.
Simple organelles without a nucleus.
There is a pseudo-nucleus; Plasmids in the cytoplasm are often used as transport vehicles in genetic engineering.
2. The metabolic type of E. coli is heterotrophic facultative anaerobic.
3. The relationship between the human body and E. coli: in the case of non-pathogenic (under normal conditions), it can be regarded as a mutually beneficial symbiosis (generally considered to be this relationship in high school); In the case of pathogenesis, it can be considered parasitic.
4. In the culture medium.
There is no need to add growth factors at the time of incubation.
Eosin blue was added to the medium, and the colonies were dark purple with a metallic luster, which could identify the presence of E. coli.
5. Application of E. coli in biotechnology: E. coli, as the host of exogenous gene expression, has a clear genetic background, simple technical operation, simple culture conditions, large-scale fermentation economy, and is subject to genetic engineering.
The attention of experts.
6. E. coli in the ecosystem.
If it lives in the large intestine, it belongs to the consumer, and if it lives outside the body, it belongs to the decomposer.
7. Its genomic DNA is a circular molecule in the nucleoid, and there can be multiple circular plasmid DNA at the same time.
8. The pseudonuclear of E. coli cells has 1 DNA molecule.
The length is about 4,700,000 base pairs.
There are about 4,400 genes distributed on the DNA molecule, and the average length of each gene is about 1,000 base pairs.
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Anonymous users2024-02-05E. coli spores are everywhere in the air, and everyone has E. coli in their large intestines, so there is no need to spread it, and it is generally mutually beneficial and symbiotic with people.
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Anonymous users2024-02-04Transmission is through food, through water, and through close contact.
Escherichia coli is more resistant to heat than other enterobacterials,55 and some bacteria still survive after 60 minutes or 60 minutes of heating for 15 minutes. It can survive for several weeks to several months in water in nature, and even longer in cooler feces.
E. coli's place in the ecosystem: if it lives in the large intestine, it belongs to the consumer, if it lives outside the body, it belongs to the decomposer.
The disease is mostly acute sepsis, the newly hatched ducklings are weak after the onset of the disease, the eyes are closed, the neck is closed, the abdominal circumference is larger, there are often diarrhea, and most of them die due to sepsis; Larger ducklings are depressed after the onset of the disease, loss of appetite, drooping wings, standing aside, head bent downward, the corners of the mouth touch the ground, the eyes and nostrils are often attached to the secretions, some sick ducks pull green loose stools, dyspnea, often due to sepsis or physical failure, dehydration death; Adult sick ducks like to lie down, reluctant to move, the abdominal circumference is swollen and sagging like a penguin when standing, there is a fluctuating sensation of fluid on palpation, and ascites is discharged by puncture. On autopsy, the liver is enlarged, bronze or bile-like, patin-green, brittle; The spleen is enlarged and has purple-black markings; ovarian hemorrhage, pulmonary congestion, hemorrhage and edema; The whole body serous membrane is characterized by acute exudative inflammation, and yellowish-white fibrinous exudate is attached to the surface of the pericardium, hepatic envelope and air sac wall; exudative inflammation of the peritoneum, yellowish ascites; catarrhal or necrotizing inflammation of the intestinal mucosa; Some sick ducks have broken yolk, and the abdominal cavity is mixed with yolk material; Some ducklings have incomplete yolk absorption and pathological changes such as metallitis. To confirm the diagnosis, it is necessary to send it to the laboratory for isolation and identification of pathogenic bacteria. >>>More
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