Enterotoxigenic Escherichia coli gastroenteritis

　　First, Etiology

　　This bacterium is a Gram-negative bacillus, with a size of (1.1～1.5)μm×(2.0～6.0)μm (viable bacteria) or (0.4～0.7)μm×(1.0～3.0)μm (stained bacteria). Most strains have peritrichous flagella, which can move, and there are also pili on the body, without spores. Some strains have a capsule. The pili are located on the surface of the bacterial body, fibrous adhesives, belonging to hydrophobic protein components, with good antigenicity, which can stimulate the body to produce corresponding antibodies. It is a facultative anaerobe, which can grow at 15～45℃ and the most suitable growth temperature is 37℃, with the most suitable pH of 7.4～7.6. On the selective culture medium for intestinal bacteria, it can ferment lactose to produce sugar, causing the indicator to change color and form colored colonies. Most pathogenic bacteria in the Enterobacteriaceae do not ferment lactose, and the colonies are colorless, which has a selective effect on the isolation of pathogenic bacteria in the Enterobacteriaceae. It produces acid and gas by fermenting various sugars and alcohols such as glucose, lactose, maltose, mannitol, etc.; the fermentation of sucrose, euonymose, raffinose, rhamnose, etc. varies with the strain. IMVC test is --, urease, phenylalanine, malonate, etc. are negative. The antigen structure is relatively complex, mainly including O, H, K 3 kinds of antigens. O antigen is a heat-stable polysaccharide phospholipid complex, currently there are 171 kinds, which is the basis for serotyping; H antigen is a heat-labile protein, up to 56 antigens have been established so far; K antigen is a capsular antigen, up to 100 kinds are known. This bacterium can survive in nature water for several weeks to several months, and can survive longer in feces with lower temperatures. It is easy to produce drug resistance. The development of drug resistance is mainly obtained by the transfer of plasmids carrying drug resistance factors (R factors).

　　Second, Pathogenesis

　　1. Invasion Escherichia coli has K antigens and pili. K antigens have anti-phagocytic effects and can resist complement and antibodies; pili help the adhesion of bacteria. The flagellum-like pili of toxigenic Escherichia coli are called colonization factors or colonization factors (colonization factor), including CFAI, CFAII. They are controlled by bacterial plasmids and can be transferred to other strains through plasmid transfer. They have strong antigenicity and can stimulate the host's immune system to produce specific antibodies. Invasive strains can invade the superficial layer of the intestinal mucosa and cause inflammation.

　　2. Enterotoxin ETEC refers to the toxin released by Escherichia coli during its growth and reproduction process. It is classified according to its heat stability into: heat-stable enterotoxin (heat-stable enterotoxin, ST) and heat-labile enterotoxin (heat-labile enterotoxin, LT). Both ST and LT are encoded by extrachromosomal genetic material plasmids and control synthesis. Some strains of EFEC produce cytotoxic substances.

　　(1) Heat-stable enterotoxin (LT): Similar to cholera toxin, it can stimulate the adenylate cyclase of small intestinal epithelial cells, converting ATP to cAMP, promoting excessive secretion of small intestinal fluid, exceeding the intestinal absorption capacity, resulting in diarrhea. Heat-stable enterotoxin (ST) activates the guanylate cyclase on the cell surface, increasing intracellular cGMP levels, leading to fluid balance disorder and causing diarrhea.

　　(2) Endotoxin: The cell wall of Escherichia coli has endotoxin activity, with the toxic site being lipid A; O-specific polysaccharides help the bacteria resist the host's defense function.

　　3. Adhesin Adhesin (BFP), also known as the pathogenic Escherichia coli adhesion factor (EAF), is a pilus encoded by a large plasmid of the bacterium, which is closely related to the adhesion. The adhesion mediated by BFP is local adhesion, and the bacteria are not uniformly distributed on the cell surface, but exist in clusters or micro-colony-like on the cell surface. At the same time, this adhesion is long-distance adhesion, and the bacterial body does not directly contact the cell, but is connected by pili.

　　4. Cadherins were previously known as EAE protein, which is a minor outer membrane protein of enteropathogenic Escherichia coli, with a molecular weight of 94kD. It has a high homology with the N-terminal region of the Yersinia invasion protein. The coding gene eaeA is located on the chromosome of the bacterium. It has recently been found that Escherichia coli O157:H7 also has a similar structure to eaeA.

　　Cadherins are the main material basis for the close adhesion and invasion of pathogenic Escherichia coli to the host cells. After binding to the corresponding receptors on the host cell membrane, it leads to the increase of intracellular Ca2+ concentration and protein phosphorylation, causing the rearrangement of the cellular cytoskeleton, forming a dense fibrous actin pad at the site of bacterial adhesion, thereby allowing the bacteria to invade the cell. At this time, the infected cells show the shedding of the brush border and the loss of microvilli.

　　5. The eaeA gene family was applied to induce mutations in EPEC containing plasmids with TnphoA insertion. As a result, 22 strains were identified as non-invasive among 329 strains, among which 5 strains had TnphoA inserted in the eaeA gene on the chromosome, proving that invasiveness is related to tight adhesion and the production of cadherins. In addition, 2 strains had TnphoA inserted below eaeA, losing the ability to adhere tightly to epithelial cells, but still able to produce cadherins. This indicates that in EPEC, there is an eae gene cluster, and the genes below eaeA are called eaeB.

　　Through genetic research and combining the above pathogenic factors, Donnenberg proposed that the pathogenic mechanism of EPEC is divided into 3 stages. The first stage is mediated by BFP encoded by bfpA on the EAF plasmid, causing the bacteria to adhere to each other and to microvilli. At the same time, the plasmid and chromosomal sites lead to initial local adhesion. The second stage involves the conversion of chromosome gene启动 signals, leading to tyrosine phosphorylation of proteins, increased intracellular calcium concentration, early disruption of the cellular cytoskeleton, alteration of microvilli, and secretion of fluid. The third stage, as the infection progresses, activates the eae gene cluster, producing cadherins that make the bacteria tightly adhere to the epithelial cell membrane, enhancing the disruption of the cell cytoskeleton. A large number of actin and myosin accumulate below the bacterial adhesion. At this time, some bacteria invade the epithelial cells.

　　Due to frequent occurrences of nausea, vomiting, diarrhea, and watery stools, the body shows obvious symptoms of dehydration and acidosis, as well as hypokalemia, hypocalcemia, and may also develop acute renal failure. Severe cases may experience soft paralysis, even respiratory muscle paralysis, arrhythmia, coma, convulsions, and other severe complications. If treatment is not timely, infants and young children may die within a few days. If early detection and treatment are made, and there are no complications, the prognosis is good.

　　Due to the differences in virulence, invasive situations, and resistance between the five different types of E. coli, the clinical manifestations are also inconsistent.

　　One type is the bacteria that only attach to the intestinal mucosa and grow and reproduce, producing enterotoxins. By activating the adenylate cyclase of intestinal wall cells, when the intracellular cyclic adenosine monophosphate (cAMP) level increases, it can promote excessive secretion of intestinal fluid (LT) in the small intestine. The excessive secretion of intestinal fluid caused by ST toxin is mediated by cyclic guanosine monophosphate (cGMP), and at the same time, enterotoxins can also damage the epithelium of surrounding blood vessels, causing diarrhea and the excretion of large amounts of watery stools (clinically similar to cholera-like diseases). Another type is the bacteria that can invade the intestinal mucosal epithelial cells, reproduce in large numbers, and produce toxic substances that cause a type of reticular effusion to flow into the intestinal cavity. Finally, the epithelial cells rupture, leading to necrosis of the intestinal mucosa and the formation of ulcers, with the stool containing pus and blood (clinically similar to dysentery-like diseases). The main lesions are mainly in the ileum.

　　How to prevent E. coli enteritis?

　　One, Managing the source of infection

　　1. Early detection:Early detection of patients is achieved through self-reporting, mutual reporting, outpatients, and round-the-clock visits. In places where an epidemic has occurred, medical observation should be especially strengthened for cooks, water suppliers, food processing and sales personnel, and caregivers. Regularly understand the stool situation, and perform stool tests when necessary to promptly identify patients and carriers. Regular follow-up should be conducted for discharged patients to understand their stool situation and whether there are symptoms and signs, and timely detection of relapse and chronic patients should be done.

　　2. Isolation and treatment:Diarrheal diseases caused by patients or carriers as sources of infection should be immediately sent to the hospital for intestinal isolation and treatment. Treatment should be timely, thorough, and the patient can only be discharged after confirmed recovery. During the isolation period, health education and management should be strengthened for the patient, who should comply with all regulations, consciously avoid contact with healthy people, and not随意 discard excreta to prevent environmental pollution.

　　Two, Cut off the transmission route

　　1. Improve water supply hygiene:The health department should regularly inspect water sources, water quality, and disinfection effects. For decentralized water supply, a good water source should be selected. Drinking water (including kitchen and lavatory water) must be disinfected. When using chlorine disinfectants, pay attention to the effective chlorine content and ensure that the residual chlorine during disinfection is maintained at 0.2-0.3mg/L.

　　2. Manage food hygiene:

　　① Regularly inquire and examine the health of kitchen staff, and immediately send suspected patients to the hospital for examination and treatment. Kitchen staff should adhere to hand washing before work and before meals (including before cooking) and after defecation. They should wear work clothes and maintain cleanliness. Kitchen staff, food service personnel, and caregivers should leave their work positions immediately after falling ill and can only return to work after a complete recovery.

　　② Implement a separate meal system, wash dishes with running water, keep bowls and chopsticks separately, and disinfect public utensils with each meal. Before eating leftover food, it should be heated thoroughly. Do not eat cold dishes or raw or semi-raw food of all kinds, do not buy, prepare, or eat moldy food. Separate raw and cooked knives, boards, and containers.

　　3. Strengthen the management of excrement:Excrement, garbage, and wastewater should be treated in a harmless manner. Toilets, animal pens, garbage dumps, etc., should be managed by专人, cleaned and flushed daily to maintain cleanliness and hygiene without flies or maggots.

　　4. Improve the environmental hygiene:Regularly clean the environment, remove garbage, and ensure that doors and windows (including toilet doors and windows) have complete fly prevention equipment. During the season when flies are active, regular spraying of insecticides should be carried out to eliminate flies.

　　5. Pay attention to personal hygiene:Through health education, develop good hygiene habits, such as not drinking unboiled water, not eating unclean fruits and vegetables, and raw or cold food, and consistently washing hands with running water before meals and after defecation.

　　6. Conduct medical protection:Wear gloves when handling patients' excrement and vomit. After contacting patients and before meals, use soap and running water to thoroughly wash hands. Rapidly take appropriate preventive measures for close contacts.

　　Three. Protect susceptible populations

　　Enhance physical exercise, pay attention to the combination of work and rest, pay attention to diet, drinking water hygiene, and personal hygiene. According to the current epidemic situation, select appropriate vaccines, and carry out vaccine prevention for key populations. In times of war, during emergency rescue operations, appropriate medication for prevention can be considered.

　　Four. Conduct a health epidemiological survey

　　1. Epidemiological investigation of the epidemic area:Conduct case investigations thoroughly, identify the source of infection and possible transmission conditions, take preventive measures to prevent the spread of the disease. During an outbreak of diarrhea, promptly organize personnel for an epidemiological investigation, identify the cause and factors of the outbreak, take effective measures to control the spread.

　　2. Management of contacts:People in close contact with the patient should be quarantined, their health status should be monitored, and special attention should be paid to prevent contamination of water sources.

　　3. Feces testing and preventive medication:All personnel at the epidemic point should have their feces tested once a day starting from the day of treatment, for two consecutive days. The first fecal sample should be taken before taking the medicine. Preventive medication can include the following:

　　Sulfamethoxazole Trimethoprim: 2 tablets twice a day for each person, for 3 consecutive days.

　　Doxycycline: The initial dose for adults is 0.2g, followed by 0.1g each time, once a day, for 3 consecutive days.

　　Tetracycline: 0.5g for adults, once every 6 hours, for 3 consecutive days.

　　D, Furazolidone: 2 times/d, 0.2g each time, taken for 3 days.

　　Children's dosage per day is calculated according to body weight: sulfamethoxazole combination 25mg, furazolidone 10mg, doxycycline 6mg.

　　4, Lifting of the epidemic point:All the above measures have been implemented in the epidemic area. All personnel should have two consecutive negative stool tests, and the epidemic can be lifted when there are no secondary cases or carriers. If there is no fecal examination condition, it can also be lifted if there are no new cases within 5 days after the treatment of the epidemic point. In special cases, such as the emergence of new epidemic areas, new strains, in the early stage of the epidemic, ports, tourist destinations, open points, and densely populated areas, epidemic point closure and strict management can be implemented.

　　OneSample collection

　　Use sterile cotton swabs to collect feces from diarrhea patients. If there is no feces, insert a moist phosphate buffer solution rectal swab into the anus 4-6cm (2-3cm for infants and young children) and rotate to collect rectal surface mucus. After collection, place it in transport or storage fluid. If it cannot be tested in time, the sample should be stored in a refrigerator at 4℃ for no more than 8h.

　　Second, enrichment and isolation culture

　　For the isolation of Escherichia coli, weak selective media such as Eosin Methylene Blue, China Blue蔷薇酸式山梨醇麦康凯 plate should be used in the primary isolation, streak separation, incubated at 35-37℃ for 18-24h, observe the colony morphological characteristics, select single colonies with purple or dark red color, size of 1-3mm, with neat edge and luster, and central convexity for identification.

　　ThreeIdentification

　　1, Preliminary identification:According to the colony characteristics, the shape and staining reaction of the bacteria on the smear, perform biochemical reactions on pure culture bacteria. Any strain that meets the corresponding results can be preliminarily identified as Escherichia coli.

　　2, Final identification:General routine tests can be done for the above preliminary identification, and final identification can be made according to the biochemical reactions listed in 'Berger's System of Bacteriology Manual' when necessary.

　　3, Identification test:Some Escherichia coli, especially non-motile non-fermenting lactose-fermenting strains, should be differentiated from Shigella. The main differential tests for the two are the acetate and glucose ammonium utilization test and the three tests for acid production from muc酸盐. Escherichia coli is all positive, while Shigella is negative.

　　(1) Pathogenic Escherichia coli:

　　A, Assumption test: Pick the culture from the dense growth area on the differential plate, perform agglutination test with three multivalent O sera of EPEC, if it agglutinates with a certain multivalent O serum, then perform a test with the monovalent O sera contained in the multivalent serum. If it agglutinates with a certain monovalent serum, then pick 3-5 single colonies and perform agglutination test with the serum.

　　B, Biochemical test: Select colonies with strong agglutination of O monovalent serum and inoculate them on triple sugar iron agar, hang indole test strips, and incubate at 36℃ for 18-20h. Any strain that produces acid from lactose and sucrose, produces acid and gas in most cases from glucose, is negative for H2S, and positive for indole can be confirmed as Escherichia coli. If the indole is negative, the V-P test must also be negative, and it cannot grow on Simmon's citrate agar, then it can be confirmed as Escherichia coli.

　　C. Serological confirmation test: Scrape the culture on triple sugar iron agar, make a bacterial suspension with physiological saline, dilute it to the concentration of MacFarland No. 3 turbidity tube, if the original titer is 1:(160-320), it can be diluted 1:40 (with 0.5% saline). In a 10mm×75mm tube, mix the diluted antiserum with the bacterial suspension in equal amounts, and observe the results after 16 hours at 50.6℃ water temperature. If agglutination appears, it can be confirmed as the O factor.

　　(2) Hemolytic Escherichia coli: Known as the feces of patients with hemorrhagic colitis, it can be streaked on MacConkey agar plates with sorbitol instead of lactose. After incubation, select 3-5 colonies that do not ferment sorbitol, and use O157 serum (it is best to use H7 serum at the same time) for slide agglutination test and tube agglutination test to determine the diagnosis.

　　The isolated strain should be inoculated on triple sugar iron agar, suspended with indole reagent paper strips, and incubated at 36℃ for 18-20 hours. The typical biochemical characteristics are acid production from lactose and sucrose, acid and gas production from glucose, negative for H2S, positive for indole, and inoculated with sorbitol fermentation tubes, which are slow fermenting.

　　(3) Toxic Escherichia coli:

　　A. Biochemical test: Select 5 colonies that can be fermented on differential plates, generally picking typical lactose-fermenting colonies, and then inoculate them on triple sugar iron agar. Hang indole reagent paper strips, and incubate at 36℃ for 18-20 hours. Strains that produce acid from lactose and sucrose, produce acid and a lot of gas from glucose, are negative for H2S, and positive for indole can be confirmed as Escherichia coli. If the indole is negative, the V-P test must also be negative, and it cannot grow on Simmons citrate agar, only then can it be confirmed as Escherichia coli.

　　B. Enterotoxin test: The virulent Escherichia coli is mainly confirmed by enterotoxin tests, which are numerous in methods. Currently in China, the double-phase agar diffusion test is used to determine LT, the intragastric gavage test with lactating rats is used to determine ST, and sometimes the ileal loop ligation test with domestic rabbits is also used to determine LT and ST.

　　Currently, genetic diagnostic methods are used to determine these two enterotoxins.

　　a. Bile-tube agglutination test: The tested strain is inoculated in a 5-point annular pattern on Elek medium, and the operation is performed twice. Incubate at 36℃ for 48 hours. Place a polymyxin B disc on the colony of each strain, and after 5-6 hours at 36℃, the enterotoxin diffuses into the agar. Make a 4mm diameter hole 5mm away from the colony center, and cover it with a drop of agar. Add 30μl of LT antitoxin to the hole, and use known LT-producing and non-toxic strains as controls. Incubate at 36℃ for 15-20 hours to observe the results. A white precipitate band appears between the bacterial plaque and the antitoxin hole as positive, otherwise negative.

　　b, Lactating mouse gavage test: Inoculate the test strain into Honda toxic broth, culture at 36℃ for 24 hours, centrifuge at 3000r/min for 30 minutes, take the supernatant after filtration through a membrane filter, heat at 60℃ for 30 minutes, add 0.02ml of 2% Evans blue solution per milliliter of filtrate, inject this filtrate into the stomach of 1 to 4-day-old lactating mice 0.1ml through a plastic tube, inoculate 3 to 4 mice at the same time, anesthetize with chloroform after fasting for 3 to 4 hours, remove all the intestines, weigh the intestines (including effusion) and the remaining body weight, the ratio of intestinal weight to remaining body weight greater than 0.09 is positive, 0.07 to 0.09 is可疑.

　　c, Rabbit ileal segment ligation test: Inoculate the test strain into Honda toxic broth, culture at 36℃ for 24 hours, centrifuge at 3000r/min for 30 minutes, take the supernatant after filtration through a membrane filter, divide the filtrate into two parts, one not heated for LT measurement; the other 60℃ heated for 30 minutes for ST measurement. Take a 2kg rabbit, fast for 1 day, anesthetize and laparotomy, take out the ileal segment, ligate it in sections of 10 to 15cm, inject 2ml of broth as a negative control in one section, and inject 2ml of filtrate from the known toxic broth culture as a positive control in another section. Inject 2ml of filtrate from the broth culture of the test strain in other sections. Suture the abdominal wall, check the abdomen 6 to 8 hours after injection for ST measurement; check the abdomen 18 hours after injection for LT measurement, withdraw the filtrate from each intestinal segment, measure its volume, and measure the length of the intestinal segment. The ratio of effusion volume (ml) to intestinal segment length (cm) greater than 1 is positive.

　　d, Serological test: Positive strains for enterotoxin test can be used with multivalent O sera and monovalent sera related to ETEC for slide agglutination test to determine the O antigen.

　　(4) Invasive Escherichia coli:

　　A, Biochemical test: Select 3 to 5 colonies on the differential plate, generally, more colonies similar to Shigella that do not ferment lactose should be selected, but lactose-fermenting dominant colonies can also be appropriately selected. Inoculate the selected colonies into semi-solid tubes, culture at 36℃ for 18 to 24 hours. Strains with motility can generally be discarded, unless serologically identified as 0124, leaving strains without motility. Inoculate the triple sugar iron agar, hang indole substrate test strips, culture at 36℃ for 18 to 20 hours, and perform lysine decarboxylase test at the same time. The typical biochemical characteristics of EIEC are: lactose, sucrose does not produce acid or produces acid, glucose produces acid, gas or no gas, negative for H2S, positive for indole, negative for lysine decarboxylase, no motility except O124, and lysine decarboxylase test can also be performed after the serological test.

　　B. Serological test: Pick up the triple sugar iron agar culture, perform a slide agglutination test with two polyvalent O sera of EIEC to determine the composition of the O antigen.

　　C. Guinea pig corneal test: Drop the bacterial fluid into the guinea pig's eyes and observe for redness, swelling, and lacrimation within 2-5 days.

　　D. ELISA test: Immunize rabbits with known EIEC or Shigella toxic strains, absorb the immune serum with isotype non-toxic strains, and determine the toxic strains of EIEC and Shigella by ELISA. This method detects the invasive peptides of the tested bacteria and can also be detected by gene probe method.

　　(5) Aggregative Escherichia coli: An important characteristic of aggregative Escherichia coli (EAEC) is the formation of characteristic aggregative adhesion around Hap-2 cells. Yamamoto found that at 37°C, this aggregative adhesion of EAEC can occur on the growth surface of some liquid culture media, forming thickly adherent aggregates, which is not observed at 25°C or 42°C. The liquid medium is best with L or M-H medium, which can be used as a preliminary identification method for EAEC. The test for the formation of aggregates in liquid media: Escherichia coli is inoculated into M-H liquid medium (Difco), incubated at 35-37°C for 18-24h. Any surface (partially settled at the bottom of the tube) forming aggregates is positive, and a uniform turbid, non-aggregated culture is negative. In 1996, Wang Mei and others conducted a simple screening test for enterotoxigenic Escherichia coli (EAggEC), comparing the test for the formation of aggregates in M-H medium with the Hep-2 cell adhesion test, and found that the consistency rate was 77%, and when including diffused and localized types, it reached 88.5%, indicating that the test for the formation of aggregates is a reliable preliminary screening method for EAggEC.

　　What kind of food is good for the body for Escherichia coli enteritis:

　　The diet should include carrot puree taken in divided doses, which is helpful for the recovery of the condition. The patient's diet should be light and easy to digest, with an emphasis on eating more vegetables and fruits, and a reasonable dietary combination, with attention to adequate nutrition. In addition, patients should also pay attention to avoiding spicy, greasy, and cold foods.

　　1. Treatment

　　1. Treatment Principles

　　Acute enteritis has a strong tendency to self-heal, and its basic treatment approach is fluid replacement and symptomatic treatment. Elderly patients, infants, children, and patients with underlying diseases or severe conditions should be given antibiotics to improve clinical symptoms and shorten the shedding period. It is noteworthy that the in vitro sensitivity test of antibiotics often does not correspond to clinical efficacy. Unless intravenous fluid replacement is necessary, oral fluid replacement is generally preferred, with the WHO-recommended glucose electrolyte oral solution containing 3.5g of sodium chloride, 2.5g of sodium bicarbonate, 1.5g of potassium chloride, and 20g of glucose (sucrose 40g or rice flour 30g can also be used).

　　Escherichia coli enteritis, for mild cases, symptomatic treatment alone is sufficient. For suspected bacteremia and severe cases, norfloxacin polymyxin or compound sulfamethoxazole can be given. The main treatment for ETEC is to correct the imbalance of water and electrolytes. For patients resistant to the above drugs, ofloxacin or ciprofloxacin can be used. Generally, fluoroquinolone drugs can be selected when the cause of diarrhea is unknown.

　　2. Treatment Plan

　　(1) General treatment: Reduce the amount of breastfeeding for infants, give oral glucose solution and normal saline, provide easily digestible food for children and adults, and supplement vitamin C appropriately.

　　(2) Fluid therapy: According to the nature and degree of dehydration, supplement electrolyte solutions and glucose solutions. Currently, a glucose and electrolyte oral rehydration salt (ORS) solution bag is widely used for convenience. For infants and young children, the initial fluid replacement volume on the first day is 100-200ml/kg according to the degree of dehydration. Adjust the proportion of sodium-containing solutions and the volume of infusion according to the degree of eye socket depression, skin elasticity, and urine output during fluid replacement. For acidosis, 5% sodium bicarbonate solution should be given promptly according to the CO2 binding capacity to correct acidosis. For infants and young children with long-term illness or malnutrition, plasma transfusion (25-50ml per time) can be given appropriately twice a week.

　　(3) Traditional Chinese Medicine treatment: Acupuncture points include Hegu, Zusanli, Dachangshu, and止泻穴. Massage and rubbing the spine to stop diarrhea. According to syndrome differentiation, use traditional Chinese medicine formulas: for spleen deficiency diarrhea, use Qi-yi Spleen Invigorating Formula; for属实热泻, use Qingre Lishi Formula.

　　(4) Antimicrobial therapy: Select sensitive drugs and use them in adequate doses for 5 consecutive days. Commonly used drugs include norfloxacin, ofloxacin, doxycycline, compound sulfamethoxazole, neomycin, kanamycin, polymyxin B, gentamicin, ampicillin, and furazolidone. Caution should be exercised when gentamicin and kanamycin are used in patients with renal damage.

　　During treatment, care should be strengthened, and diapers should be changed frequently for children, and the buttocks should be washed with warm water after each defecation to maintain cleanliness and prevent skin infection.

　　II. Prognosis

　　Early detection and treatment, without complications, and good prognosis.