Brief introduction of enterobacteriaceae pneumonia

Table of Contents 1 Pinyin 2 English Reference 3 Overview 4 Disease Name 5 English Name 6 Classification 7 ICD Number 8 Epidemiology 8.1 Infection Source 8.2 Infection Pathway 8.3 Susceptible Population 9 Etiology 1 Pathogenesis 11 Clinical manifestations of Enterobacteriaceae pneumonia 12 Complications of Enterobacteriaceae pneumonia 13 Laboratory examination 13.1 Hemogram 13.2 Urine routine, Renal Function and Liver Function 13.3 Sputum Bacterial Culture 14 Auxiliary Examination 15 Diagnosis 16 Differential Diagnosis 17 Treatment of Enterobacteriaceae Pneumonia 17.1 Treatment Principles 17.2 Antibacterial Treatment 18 Prognosis 19 Prevention of Enterobacteriaceae Pneumonia 2 Related Drugs 21 Related Examination Attachment: 1 Chinese patent medicine for the treatment of enterobacterial pneumonia 2 drugs related to enterobacterial pneumonia 1 Pinyin

Chá ng g m n j ū n f è i y á n 2 English reference

Overview of enterobacterial pneumonia 3

Enterobacterial pneumonia was extremely rare in the past. In recent decades. With the increasing application of broad-spectrum antibiotics and respiratory medical devices, Enterobacter pneumonia has accounted for 9.4% of hospital-acquired pneumonia, ranking fourth after Pseudomonas aeruginosa pneumonia, Staphylococcus aureus pneumonia and Klebsiella pneumoniae pneumonia, among which Enterobacter cloacae and Enterobacter aerogenes are the most common causes. Clinically, Enterobacteriaceae pneumonia mostly occurs in patients with weakness or immunosuppression, which is easily caused by contaminated medical devices, often accompanied by bacteremia and poor response to various antibiotics.

Enterobacteriaceae pneumonia is similar to other gram-negative bacilli pneumonia. Sudden onset, sudden chills and fever. The body temperature is often between 37.7 and 38.8℃. Cough is obvious, expectoration is more, showing mucus purulent, but unlike Klebsiella pneumoniae, hemoptysis and bloody sputum are rare. If the lesion is extensive, you may have difficulty breathing. Physical examination may cause shortness of breath and cyanosis. 4 disease name

Enterobacter pneumonia

5 English name

enterobacter pneumonia 6 classification

Respiratory Department >; Infectious diseases > Bacterial pneumonia 7 ICD number

J15.5 8 epidemiology 8.1 infection source

Enterobacter is a bacterial infection, and the carrier is the main source of infection. It is rare for normal people to carry bacteria, but the carrier rate of doctors and nurses in hospitals is higher than that of the general population, and critically ill patients in hospitals are the main carriers. Mayhall et al. reported that there were many Enterobacter cloacae infections in a burn ward. During the outbreak, 5% of patients carried the bacteria. Patients with enterobacteriaceae living in the intestine or oropharynx may be the endogenous infection source of enterobacteriaceae pneumonia. In addition, medical devices such as atomizer, oxygen humidifying bottle and aspirator in hospital wards may become the source of infection. 8.2 route of infection

(1) respiratory inhalation: including accidental inhalation of nasopharyngeal secretions and direct inhalation of Enterobacteriaceae in the air, is the main route of infection of Enterobacteriaceae pneumonia. It is generally believed that bacteria contaminated by eating or other means are often parasitic in the oropharynx first. Then it enters the lower respiratory tract with the secretion of oropharynx by mistake. This route of infection is rare in healthy people. But in patients with serious diseases, a large number of long-lasting reproduction may occur. Some people observed the patients in intensive care unit, and found that in patients who were using ventilator, heart failure after operation, shock or receiving antibiotic treatment, within 24 hours, 22% of the patients had gram-negative bacilli growing in the oropharynx, and by the end of one week, it was as high as 45%, among which the proportion of Enterobacter aerogenes increased significantly. Enterobacter respiratory tract accounts for 68% of patients with respiratory failure caused by various reasons.

(2) Contaminated equipment infection: Respiratory equipment is an important infection route that causes Enterobacteriaceae pneumonia. About 8% of the atomization or humidification devices in respiratory therapy equipment are contaminated by pathogenic bacteria, among which Enterobacter cloacae, Enterobacter aerogenes and Enterobacter agglomerans are also common contaminated bacteria. Because the atomizer with liquid storage can produce liquid particles as small as 1mm and reach the lower respiratory tract, it is reported in the literature that the atomizer has the most chance of pollution. In addition, oxygen humidification bottle is also an important transmission route. In 1993, a hospital in China was polluted by Enterobacter cloacae because of oxygen humidification bottle, resulting in an outbreak of Enterobacter cloacae pneumonia in 31.3% of inpatients.

(3) Blood-borne spread: Enterobacteriaceae is an important cause of bacteremia and septicemia in some hospitals, especially in surgical intensive care units. The early literature reported that the rate of gram-negative bacilli septicemia was 3.7% ~ 23%. In recent years, the incidence seems to be increasing, reaching as high as 4%. Therefore, enterobacteriaceae pneumonia may become the pulmonary manifestation of systemic enterobacteriaceae infection. 8.3 susceptible population

Enterobacter is a conditional pathogen, and only when the patient's local and systemic resistance is low and the normal flora is out of balance will it colonize and reproduce in the lower respiratory tract and cause infection.

(1) Patients who have recently undergone surgery: Relevant data show that the incidence of enterobacterial pneumonia is not only related to surgery, but also related to the type and time of surgery. The incidence of pneumonia in surgical patients is 3.91 times higher than that in internal medicine patients, and it can be as high as ten times in patients undergoing thoracoabdominal surgery.

(2) Patients with primary diseases that are prone to aspiration, such as general anesthesia, cerebrovascular accident, drug overdose, alcoholism and brain injury, cause disturbance of consciousness; Patients with neck, pharynx and esophagus diseases that affect swallowing function may inhale Enterobacter bacteria colonized in oropharynx and cause infection. For example, nasal feeding tubes provide convenient conditions for Enterobacter to enter the lower respiratory tract. The survey results show that the incidence of pneumonia with mechanical ventilation is 21 times higher than that without mechanical ventilation. Even paying great attention to disinfection of instruments can not further reduce the incidence of nosocomial pneumonia including Enterobacter.

(3) people with low immune function: some elderly people, patients with chronic diseases, diabetes, cardiovascular diseases and renal failure; Tumor patients receive radiotherapy and chemotherapy; Application of antimetabolites in organ transplantation and connective tissue diseases; Both corticosteroid therapy for hematological diseases and chronic alcoholism can cause decreased immune function and lead to enterobacterial infection.

(4) Patients who use antibiotics in large quantities or neutralize gastric acid: the balance of normal flora in the body is destroyed or the pH of the stomach is increased, which leads to the proliferation of a large number of conditional pathogens such as Enterobacter. 9 Etiology

Enterobacter belongs to Enterobacter E.cloacae, Enterobacter E.aerogenes, Enterobacter E.agglomerans, Enterobacter Gao Fei, Enterobacter E.sakazakii and Enterobacter Taylor. Enterobacter cloacae and Enterobacter aerogenes are important conditional pathogens in clinic, which can cause pneumonia, septicemia, urinary tract infection and meningitis. Enterobacter agglomerans is an important pathogen of nosocomial infection, which can pollute infusion and cause sepsis and other infections.

Enterobacter is widely distributed in the natural environment. It can be found in soil, sewage, rotten vegetables and dairy products. Enterobacter cloacae and Enterobacter aerogenes can colonize the gastrointestinal tract and respiratory tract and are part of normal flora.

the biological characteristics of Enterobacter are similar. The representative bacterium is Enterobacter cloacae. The thallus is 1.2 ~ 3.2 μ m long and .6 ~ 1. μ m wide. Motivated, with flagella all over. Most fermented mannitol, sorbitol, lactose, sucrose, arabinose and rhamnose do not produce hydrogen sulfide and indole. VP reaction is positive, MR reaction is negative, gluconate is positive, and ornithine decarboxylase is produced. All bacteria grow well on common culture medium. The colony of each strain is not characteristic and needs a series of biochemical reactions to be identified.

Enterobacter can be classified by serum, bacteriocin, biochemical test and phage. Various methods have different functions, but they can verify and make up for each other. In the American Central Public Health Laboratory, the most reliable serological method is used as the main method to identify strains. The strains with the same serotype were further typed by phage. It has been proved that these typing methods are effective in most cases. But in some cases, biological typing is a useful and proven method. At present, Enterobacter cloacae is divided into 53 O antigens and 57 H antigens, and 79 serotypes are separated from 17 strains. 1 Pathogenesis < P > It is generally believed that Enterobacteriaceae, including Enterobacteriaceae, is different from non-Enterobacteriaceae, such as Pseudomonas aeruginosa. Before entering the lower respiratory tract, it often resides in the oropharynx, and then reaches the lower respiratory tract through inhalation or direct dissemination.

whether bacteria enter the lower respiratory tract or not depends on the number and duration of bacteria adhering to the mucosa. The more bacteria are attached, the longer it lasts, and the greater the possibility of infection. According to the research, besides the immune function of patients' whole body and lower respiratory tract, the structure of airway epithelium, the surface structure of Enterobacter and local microenvironment are all important factors affecting adhesion.

In airway epithelium, many critical diseases lead to the increase of bacterial receptors on epithelial cells, thus increasing bacterial adhesion; The cilia function of airway epithelial cells is abnormal, which reduces the clearance of invasive bacteria; The decrease of fibronectin concentration on the surface of mucosal epithelial cells reduces the blocking of bacterial binding sites and can increase the colonization of bacteria in lower respiratory tract. The airway mucosa is damaged by intubation or sputum aspiration, the basement membrane is exposed, and bacteria may also adhere to the connective tissue under the mucosa.

In terms of bacteria, the number of bacterial fimbriae, the ability to secrete mucus, the decomposition activity of fibronectin and the substances produced by them, such as cilia stabilizing substances, proteases and mucin degradation products, can all affect the colonization in the lower respiratory tract. Most strains of Enterobacter have type I fimbriae, and a few can also produce type III fimbriae and/or MR adsorbents, which have strong adhesion. In addition, some bacteria can produce substances that affect the function of cilia and reduce the removal of bacteria. Enterobacter may also decompose fibronectin to expose the bacterial binding sites on the surface of mucosal epithelial cells.

In the micro-environment of airway mucosa, the change of chemical composition and characteristics in airway secretions mainly affects the colonization of bacteria. First of all, some primary diseases increase the pH of airway secretions and increase the adhesion of bacteria. Secondly, when airway inflammation occurs, neutral elastase decomposes IgA and fibronectin, increasing bacterial adhesion.

Pathological changes: Enterobacteriaceae pneumonia, mostly bronchopneumonia. It often involves many parts, more than half of which are bilateral, and lobar consolidation is rare. Inhalation infection is more common in the lower lungs. Inflammation starts from bronchi, and causes suppurative inflammation, consolidation and necrosis of surrounding tissues through the wall of bronchioles, forming multiple tiny abscesses. In the case of hematogenous spread, perivascular infiltration and nodular pulmonary infarction first occur, and then a large number of neutrophils infiltrate, resulting in multiple micro-abscesses.

If the treatment is delayed, the small abscess may fuse to form a large abscess, no matter what the route is. If subpleural involvement is involved, purulent pleurisy may also occur. Clinical manifestations of Enterobacteriaceae pneumonia < P > Enterobacteriaceae pneumonia is similar to other gram-negative bacilli pneumonia. Sudden onset, sudden chills and fever. The body temperature is often between 37.7 and 38.8℃. The cough is obvious, the amount of expectoration is more, and it is mucus purulent, but unlike Klebsiella pneumonia, hemoptysis and bloody sputum are rare. If the lesion is extensive, you may have difficulty breathing.

physical examination may cause shortness of breath and cyanosis. Wet rales are often heard in both lungs, and consolidation signs in the lungs are rare. If it is a blood-borne infection, pulmonary signs are sometimes absent, but manifestations of extrapulmonary infections such as urinary tract and digestive tract are often found. 12 Complications of Enterobacteriaceae pneumonia < P > One of the common complications of Enterobacteriaceae pneumonia is bacteremia. It is reported in the literature that among all kinds of enterobacteremia, 11% are infected by respiratory tract and then develop into bacteremia, which is second only to those infected by abdominal organs and urinary system. Therefore, when it is suspected that lung infection is caused by blood-borne spread or accompanied by bacteremia, blood culture should be carried out. If Enterobacter is positive, the diagnosis can be made. 13 laboratory examination 13.1 hemogram

The total number of white blood cells can be increased or normal, but neutrophils often increase significantly, and anemia is more common. 13.2 Urine routine, renal function and liver function < P > Patients with Enterobacteriaceae septicemia complicated with pneumonia may have abnormal urine routine, renal function and liver function. 13.3 Sputum bacterial culture < P > Sputum bacterial culture is the only way to diagnose Enterobacter pneumonia. Clinical expectoration is contaminated by other bacteria in the oropharynx, and samples can be obtained by puncture through cricothyroid membrane, percutaneous lung puncture and fiberoptic bronchoscopy. If expectoration culture is adopted, the specimen should be treated before culture and suitable selection medium should be applied to improve the reliability of the results.

(1) Treatment of expectoration: The expectoration is washed with normal saline for 5-9 times (which can reduce the number of contaminated bacteria by 1 times on average) and then directly smeared. If the white blood cells are > 25 and the squamous epithelial cells are < 1 under low magnification, take this sputum and add 1% ~ 2% protease or acetylcysteine to incubate at 37℃. When the concentration of bacteria is more than ＞16/ml, it is considered that culture is of diagnostic significance, and a series of biochemical reactions and typing are further carried out to determine the strain, strain and type.

(2) Selection of culture medium: Because the concentration of Enterobacter in sputum samples is sometimes low, it is necessary to use selection of culture medium to improve the positive rate of culture. The composition of the selected culture medium is 2% cellobiose, .1% yeast extract, .3% sodium deoxycholate, 1μg/ml cephalosporin, 1% agar and Andrade's indicator. After most Enterobacter cloacae were cultured at 37℃ for 24 hours, pigment was produced due to the change of pH, and most fecal coliforms grew slowly or not at all. Enterobacter aerogenes can also grow on this medium. 14 auxiliary examination < P > Chest X-ray examination often shows bronchopneumonia in both lower lungs, but a few of them only see increased lung texture without obvious infiltration of lung parenchyma. In a few patients with inhalation infection, a large range of consolidation shadow can be seen in the posterior segment of the upper lobe and the dorsal segment of the lower lobe of the right lung, with cavities in between, but it is far less common than Klebsiella pneumoniae pneumonia. In the case of blood-borne infection, the chest radiograph showed that the density of irregular nodules increased, with a diameter of 4 ~ 1 mm, which spread all over the lung. If the disease develops, the nodules will be enlarged and fused. 15 < P > The clinical manifestations of Enterobacteriaceae pneumonia are not characteristic, which is similar to other Gram-negative bacilli pneumonia, and it is difficult to make a diagnosis only by clinical manifestations. High-risk groups during hospitalization