The pathogenic factors of Enterobacteriaceae are described.

1) Endotoxin: It can cause fever, white blood cell changes and metabolic changes, and in severe cases, it can cause shock. (2) Enterotoxin: can cause diarrhea. (3) Other phenogens: such as the ability to penetrate the intestinal epithelium and adhere to the mucosa.

1) Internal toxicity: It can cause fever, white blood cell changes and metabolic changes, and in severe cases, it can lead to shock.

(2) Enterotoxin: can cause diarrhea.

3) Other genres: such as the ability to penetrate the intestinal epithelium and adhesion to the mucosa.

Answer]: C chooses A and believes that pathogenic E. coli only causes intestinal infection, such as diarrhea, which is common in clinical practice. In fact, pathogenic Enterobacter grandiosis can not only cause intestinal infection, but also extraintestinal infections mainly urinary tract infections, such as urethritis, pyelonephritis, peritonitis, appendicitis, surgical wound infection, etc.

In addition, in infants, the elderly, or immunocompromised people, endotoxins and exotoxins can cause sepsis at the same time.

Answer] :d this question examines the structural characteristics of Enterobacteriaceae in Zenzhi. Most of the Enterobacteriaceae have flagella, and few teaching aids only have capsules, which have pilia and plasmids, and do not form buds.

Common features of Enterobacteriaceae;

1 Medium-sized G-bacilli, non-sporous, mostly with flagella and fimbria.

2 Nutritional requirements are not high.

3 Biochemical reactions are active, and Enterobacter can decompose a variety of sugars and proteins, among which pathogenic bacteria generally do not decompose lactose, while non-pathogenic bacteria mostly decompose lactose for preliminary identification.

4. The antigen structure is complex, including bacterial (O) antigen, flagellar (H) antigen and capsule or envelope antigen.

5 Resistance is not strong.

6. It is easy to produce drug resistance mutations and virulence mutations.

Common features.

Morphology and copy structure: small to medium-sized Gram-negative bacilli with obtuse circles at both ends, without spores, most with flagella, most with fimbria, and a few with capsules or capsules.

Culture characteristics: aerobic or facultative anaerobe, well grown on ordinary medium, medium smooth colonies. Some bacteria appear hemolytic on blood agar plates, and they grow uniformly and turbidly in liquid culture.

Biochemical reactions: Biochemical reactions are lively, and generally speaking, the strength of a biochemical reaction is inversely proportional to its pathogenic effect. The lactose fermentation test is of great significance in the preliminary identification of intestinal pathogenic and non-pathogenic bacteria, the former generally does not decompose lactose, and most non-pathogenic bacteria can decompose lactose.

Resistance: not strong, heat 60 after 30 minutes and die. Bile salts, brilliant green, etc. have a selective effect on non-pathogenic bacteria such as Escherichia coli, and selective medium for enterobacter can be prepared to isolate intestinal pathogenic bacteria.

Mutation: Prone to the emergence of mutant strains. The most common are changes in drug resistance transfer, toxin production, and biochemical reactions. This is important in pathogenicity, bacteriological diagnosis, and prevention.

Pathogens: Endotoxins are the main pathogenic substances of Enterobacteriaceae. Some Enterobacteriaceae produce exotoxins to cause disease.

Mode of transmission: Contaminated drinking water and food, transmitted through the digestive tract.

Escherichia coli (, Gram-negative bacillus. Resident bacteria in the human body. It can be divided into five types.

Answer] Brother: B

Escherichia coli is an important normal flora in the intestine, fermented lactose produces acid and produces dusty mold gas, and the imvic test is ++-

Answer]: B The flora in the intestinal tract of normal people is mainly anaerobic bacteria, and a few are aerobic bacteria. The normal flora is bacteroides, lactobacillus, Escherichia coli and enterococci, etc., and there are still a few pass-by bacteria, such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, aerogenes, Proteus, perfringens, Candida albicans, etc.

The microbial flora of the two bucket slag groups maintained a certain number and proportion, and restrained each other to maintain balance. When the body's resistance is reduced or a large number of broad-spectrum antibiotics and hormones are abused for a long time, the normal flora can be inhibited, and the drug-resistant passerby bacteria can multiply excessively, resulting in intestinal flora imbalance.