Klebsiella pneumoniae pneumonia

Introduction to Klebsiella pneumoniae pneumonia Klebsiellapneumoniae, also known as Klebsiella or Friedlander, is the first known Gram-negative bacillus that causes pneumonia. In the past two or three decades, GNBP has become an important disease in modern medicine entering the era of antibiotics with the change of susceptible population, the wide application of antibacterial drugs and the changes of drug-resistant bacteria and the improvement and popularization of various microbial detection technologies. . basic knowledge The proportion of illness: 0.052% Susceptible people: no special people Mode of infection: non-infectious Complications: pneumothorax meningitis pericarditis

Causes of Klebsiella pneumoniae pneumonia

Klebsiella infection (40%):

Klebsiella pneumoniae is negative for Gram staining, inactive, capsule, paired or short-chain, easy to grow on common medium, colony on solid medium is higher than surface, smooth and sticky is characteristic, according to pod Different membrane antigen components, Klebsiella pneumoniae can be divided into 75 subtypes, causing pneumonia to be mainly 1 to 6 type, can quickly adapt to the host environment and long-term survival, susceptible to various antibiotics, pneumonia pneumonia is more common in the middle In the elderly, any condition that causes impaired immune function can be a cause of infection, such as hormones and immunosuppressive drugs, and the use of antimetabolites to cause systemic immune dysfunction and various serious diseases (such as tumor, diabetes, chronic liver disease). , leukopenia, leukemia, etc.; some invasive tests, traumatic treatment and surgery, the use of contaminated respirators, nebulizers, etc. have the potential to cause infection, hand spread of hospital staff, patients and chronic germs Carriers are the source of the bacteria.

The lung's own defense mechanism is low (25%):

When Klebsiella pneumoniae enters the alveoli, the lung's own defense phagocytic system first self-defense to prevent infection. The main anti-Klebsiella pneumoniae in the alveoli is polymorphonuclear granulocytes (PMN). Rehm et al. : Neutrophil-deficient mice can quickly clear Staphylococcus aureus in the alveoli, but can not eliminate Klebsiella pneumoniae. Studies have shown that the tiny capsule of Klebsiella pneumoniae can prevent phagocytic cells from entering the center of infection. In the region, from the animal model of Klebsiella pneumoniae pneumonia, it can be found that the main reason for the strong pathogenicity of the thick capsular strain is that it is resistant to phagocytosis in animals. When the bacteria invade the alveoli, the alveolar cavity is filled. There are a large number of neutrophils, and the process of PMN phagocytosis of Klebsiella pneumoniae in the alveolar cavity can be observed by microscopy. The chemokine is released into the alveoli by the stimulation of various lymphatic chemokines in the lung, and PMN is induced. Continuously from the circulation to the alveolar cavity, the chemotactic component is mainly complement within 4 to 6 hours after the start of the reaction, and then 12 to 24 hours is the role of non-complement chemokine.

Endotracheal intubation (20%):

Endotracheal intubation is a colony-intensive device. According to an electron microscopic examination, colonies can be seen in 95% of the cannula, 86% of which are completely covered by colonies. The reason is: A. Intubation damages the pharynx and destroys the nature of the host. Defence mechanism, B. Destroy the cleansing effect of airway cilia, C. Destroy swallowing reflex and activity, D. Cannula can not be replaced frequently, mixed infection inside and outside when sucking, in view of the above reasons, tracheal intubation directly crosses the pharynx The barrier, combined with leakage of secretions around the cuff, allows bacteria to enter the lower respiratory tract directly.

Pathogenesis

1. Susceptible population Klebsiella pneumoniae pneumonia is an opportunistic infectious disease, its occurrence and development are dependent on a certain pathological basis, common susceptibility factors include:

(1) Patients with chronic diseases: common chronic alcoholism, diabetes, chronic heart disease, lung disease, cancer and leukopenia patients.

(2) Long-term treatment with a variety of antibiotics, glucocorticoids, immunosuppressive drugs and cytotoxic drugs.

(3) Patients who have been treated for a long time in the intensive care unit (ICU), including postoperative surgical monitoring patients and advanced neuromuscular diseases.

(4) Patients using respiratory therapy devices, such as mechanical ventilation and aerosol therapy, the NP of such patients is the focus of attention in recent years, and its incidence and mortality are much higher than those of Klebsiella pneumoniae pneumonia. Average.

2. Sources of pathogens The main source of pathogens is patients and carriers of chronic pathogens (such as chronic alcoholism). There are several ways to spread bacteria:

(1) Hand spread of staff in the hospital, home care workers and other related personnel: The main reason is that the preventive measures for disinfection and cross-infection are not strictly implemented.

(2) Device transmission: common includes nebulizer, ventilator and its pipeline, tracheal intubation, nasal feeding tube, etc.

1 Nebulizer: It is a common source of infection. In addition to causing cross-infection, it can cause environmental pollution. According to Merlz, the fulminant Pneumoniae pneumoniae that occurs in Bilevui Hospital is caused by nebulizer contamination.

2Ventilator: During the mechanical ventilation process, due to the closed circuit of the pipeline connected with the patient's respiratory tract, combined with environmental pollution, poor disinfection, and untimely replacement, the colonization rate of the colony in the pipeline is high, and at the same time due to the gas The temperature difference between the compression and the pipeline and the surrounding environment causes the water and gas in the pipeline to agglomerate (especially at the end of the gas pipe). It is reported that the ordinary non-heated pipeline has a water vapor condensation amount of 20 to 40 ml per hour, which is the survival of bacteria. In the main place, it is reported that in the pipeline water close to the intubation, the amount of bacteria per ml exceeds 200,000. Turning the patient's body position will cause the bacteria-containing water to flow directly into the lower respiratory tract. At present, there are few independent heating pipes. It is expensive and maintenance is cumbersome. It is very difficult to solve immediately. According to the requirements of the US Centers for Disease Control (CDC), the pipeline should be replaced once every 24 hours. However, clinical practice has found that the number of bacteria in both is compared with the 48h replacement pipeline. There is no difference, and even some literatures indicate that the incidence of tube pneumonitis replacement is higher every 24 hours. It depends on the clinical monitoring results and actual conditions. According to the literature report, patients receiving mechanical ventilation have lungs. The incidence of inflammation is 7 to 21 times that of unaccepted people, of which Klebsiella pneumoniae is one of the most common pathogens.

(3) Colony colony of pharynx: The pharynx is the most common site of Klebsiella pneumoniae and is the direct source of pneumonia. The detection rate of Klebsiella pneumoniae in normal people is less than 1%, and severe The rate of Gram-negative bacilli was as high as 70% in patients with repeated pharyngeal secretions. According to one study, 22 patients (84%) of 26 patients with acquired Klebsiella pneumoniae in an ICU. In the pharynx, Klebsiella pneumoniae was detected. The colony of the pharynx is closely related to the adsorption capacity of the pharyngeal epithelial cells. On the surface of the pharyngeal epithelial cells, there are corresponding bacterial adsorption receptors. Under normal circumstances These receptors are covered by pharyngeal fibronectin, but under pathological conditions (alcoholism, nutritional imbalance, smoking, application of broad-spectrum antibiotics and endotracheal intubation, etc.), various non-specific proteases are released into the lumen, they The interleukins on the surface of the epithelial cells can be digested, and at this moment the receptors are exposed, and the bacteria will "chain-like" the adsorption.

Klebsiella pneumoniae has a very high affinity with pharyngeal epithelial cells, but strangely, it has no brush-like edge for adsorption purposes, so its adsorption principle is still unclear. The oropharyngeal survival of Klebsiella pneumoniae can be It is often for several months, which is especially true in patients with chronic alcoholism. According to statistics, about 29% of chronic alcoholism patients are infected with Klebsiella pneumoniae, and according to a patient who is discharged from hospital after pneumonia recovery A follow-up survey of bacteria found that more than 75% of patients disappeared after 4 weeks of discharge (including Pseudomonas aeruginosa, Staphylococcus aureus, etc.), but most of Klebsiella pneumoniae persisted until the end of the investigation. % Klebsiella pneumoniae colonies have not disappeared.

The factors affecting the colonization of Klebsiella pneumoniae colonies are:

1 Changes in host cells: Each receptor on the host epithelial cells receives the corresponding bacteria, and cyclosporin A can inhibit the adsorption capacity of the receptor on Klebsiella pneumoniae.

2 bacterial changes: This includes whether the bacteria itself has a capsule, the type of surface adsorbate and the characteristics of external contact release, etc., the surface adsorbate of Klebsiella pneumoniae is still unknown,

3 changes in the local microenvironment: the maximum impact on the pH value in the environment, when the pH is 6.5 ~ 7.2, the adsorption capacity of the bacteria can be dramatically increased to the highest level, in addition, the concentration of mucin and protease in the secretion of sputum and oropharynx Elevated, decreased IgA levels, can increase the adsorption capacity, inappropriate application of antibiotics, eliminate the inhibition of gram-negative bacilli (such as Streptococcus), can also increase its colonization and growth.

(4) Colony colonization of the stomach: The stomach of the normal person maintains sterility due to the action of the acidic barrier. The research in the past decade has shown that the environmental changes in the stomach can also cause the colony to colonize and become Klebsiella pneumoniae. An important source of intestinal resident pharyngeal transplantation, the pathological conditions that cause the increase of gastric colonies are:

1 is too old, the stomach itself has various functions,

2 gastric acid deficiency, acidic barrier disappears,

3 various acute, chronic gastrointestinal diseases,

4 nutritional imbalance,

5 Apply antacids and/or H2 receptor antagonists. When the stomach acid is deficient or the pH is raised, the number of bacteria in the gastric juice can be as high as 1 million to 100 million per ml. In addition, abnormal reflection will cause the stomach to colonize. Pharyngeal reflux, the formation of pathogens of pneumonia and bronchitis, studies have shown: when the gastric juice pH < 3, Klebsiella pneumoniae rarely exist, according to de Frock et al, pathological conditions, the new gram-negative pharynx Bacterial colonies are associated with bacteria found in the feces in advance, and the pharyngeal colonies change with the change of colonies in the feces during hospitalization. McAedingham selectively decontaminates the digestive tract and finds that the disinfection group has a lower respiratory infection rate. The control group was 6 times lower, and the pharyngeal and rectal colonies were also significantly reduced. In order to prevent the use of antacids and/or H2 receptor antagonists in stress ulcers in critically ill patients, secondary pharyngeal colony colonization increased, resulting in respiratory infections. The increase has been confirmed by many clinical research institutes.

4. Intra-tracheal inhalation (aspiration) is the key to the onset of pneumonia. 70% of normal people may have aspiration during sleep, but whether it is caused by aspiration after aspiration is the key to the concentration of pharyngeal bacteria to reach a certain concentration. Studies have shown that gram-negative bacilli colonies in the pharynx are a marker of defects in the respiratory defense of critically ill patients. Once the bacteria inhale the lower respiratory tract, they can develop pneumonia. In addition, in addition to the dense colony of the pharynx, the following factors can also cause gas. Increased inhalation in the road:

1 confusion or coma,

2 sphincter dysfunction,

3 gastric emptying delay and activity weakened,

4 swallowing function is abnormal,

5 leaks of bacteria around the tracheal intubation cuff.

5. Pathological changes Primary Klebsiella pneumoniae pneumonia is mostly distributed in large leaves, which is common in the upper lobe of the lung, especially in the upper right lobe. Secondary pneumonia is mostly distributed in the lobule, which is a plaque-like bronchial pneumonia. Multiple lobe, bilateral and lobular distribution are rare, and the overall pathology is similar to pneumococcal pneumonia, but it develops rapidly and has no significant changes in pneumonia, but has its own characteristics:

1 An autopsy lesion of the lung lobe, the cut surface of which can be seen as mucus-like exudation, or can pick up a thick filamentous exudate, which is a characteristic change of its pathology.

2 lung tissue destruction is rapid, multiple abscesses or single large abscess can be formed within 4 days, the alveolar wall is destroyed, the alveolar atrophy is caused, the lung volume is reduced, the main pulmonary vessels can be embolized, causing secondary lung gangrene and necrosis.

3 often combined with pleural invasion, pleural fibrinous exudation, adhesions, the incidence rate is about 25%, and even combined with pericardial effusion,

4 In the early histological examination, edema fluid, monocytes and bacteria were observed. In the later stage, the alveolar wall was destroyed. There were a large number of polymorphonuclear neutrophils, and the fibrous tissue proliferated actively, which was prone to mechanical changes.

5 can cause intrapulmonary hemorrhage, pus gas chest, pericarditis, bronchiectasis and other changes, some can become chronic Klebsiella pneumonia changes.

Klebsiella pneumoniae pneumonia prevention

1. Gastrointestinal decontamination treatment This is a commonly used preventive measure in Europe in recent years, mainly for susceptible populations of nosocomial infections. The purpose is to remove colonization and growth of colonies in the gastrointestinal tract. And selective gastrointestinal decontamination, commonly used for the latter, it is by nasal feeding or oral gastrointestinal non-absorbed polymyxin B, tobramycin (gentamicin or neomycin, etc.) and amphiric mold B, for 5 days, and the daily application of cephalosporin, remove aerobic bacteria from the oropharynx and gastrointestinal tract without reducing the number of anaerobic bacteria, the preventive effect is particularly obvious in Gram-negative bacilli, according to the author According to statistics, the decontamination group has almost no pneumonia and respiratory infections (individually resistant to infection) of Klebsiella pneumoniae.

2. Protecting the acidic barrier of the stomach mainly in the prevention of stress ulcers, the use of sucralfin drugs, which can prevent stress ulcer bleeding, and because it has adsorption of gastric mucosa, change gastric mucus, increase The content of prostaglandin E2 (PGE2) in the gastric cavity and the absorption of pepsin does not change the acidic environment in the stomach, thus effectively preventing ulcers and preventing infection. According to the literature, sucralfate is still intrinsic. Bactericidal activity, a series of studies showed that the incidence of pneumonia in the application of antacid group was 23% to 35%, and the incidence of pneumonia in the application of sucralfate group was 10% to 19%.

3. The biological prevention method for biological prevention of Klebsiella pneumoniae pneumonia is still in the experimental stage. Held et al. use the IgM monoclonal antibody (MAb) induced by Klebsiella pneumoniae capsular polysaccharide (CPS) to be injected into experimental animals for prevention. Klebsiella pneumoniae pneumonia, compared with the control group, regardless of organ involvement rate, the number of bacteria in infected tissues, histological changes in the lungs, etc., the prevention group was far superior to the control group (P <0.01), but this MAb still There is no effect of preventing Klebsiella pneumoniae from entering the lungs, but accelerating the absorption of infection and enhancing the ability of the lung to sterilize. In addition, there are some similar reports, but mature vaccines and antibodies have not been used in clinical practice and further research is needed.

Klebsiella pneumoniae pneumonia has endangered humans for more than a century. With the development of science, the continuous improvement of examination and treatment methods, and the deepening of human understanding, it is believed that it can further reduce its morbidity and mortality, and achieve greater improvement.

Klebsiella pneumoniae pneumonia complications Complications, pneumothorax, meningitis, pericarditis

The comorbidities include empyema, pneumothorax, pericarditis, meningitis and multiple arthritis.

Symptoms of Klebsiella pneumoniae pneumonia Common symptoms Chest pain, cold war, diarrhea, low fever, nausea, difficulty breathing

1. Symptoms start suddenly, chills, high fever, cough, purulent sputum, brick red jelly is characteristic, 80% of patients have chest pain, mainly caused by inflammation invading the parietal pleura, some patients have gastrointestinal symptoms, such as nausea , vomiting, diarrhea, jaundice, etc., systemic weakness, some patients see symptoms of upper respiratory tract infection, very few patients show chronic disease, can also be delayed from the acute course of disease, manifested as low fever, cough, weight loss.

2. Signs of acute illness, difficulty breathing, cyanosis, a small number of patients can develop jaundice, shock, lungs can be heard and wet voice, white blood cells and neutrophils, sputum culture positive.

Middle-aged and elderly men, chronic alcoholism, chronic bronchitis or other lung diseases, diabetes, malignant tumors, organ transplantation or neutropenia and other immunosuppression, or patients with artificial airway mechanical ventilation, fever, cough, Cough, dyspnea and pulmonary wet voice, increased blood neutrophils, combined with X-ray inflammatory infiltration of the lungs suggest bacterial pneumonia, should consider the possibility of pneumococcal pneumonia, especially when penicillin or When the treatment of erythromycin and other macrolide antibiotics is ineffective, the clinical manifestations of pneumococcal pneumonia, laboratory and X-ray examination are mostly non-characteristic. Although cough brick red sputum is a typical performance, it is rare in clinical practice. Microbiological examination is the only basis for the diagnosis of pneumonia pneumonia, and is also an important method to distinguish from other bacterial pneumonia.

Examination of Klebsiella pneumoniae pneumonia

1. Blood examination Most patients have increased white blood cells, ranging from (150 ~ 200) × 109 / L, including poisoning particles and nuclear left shift phenomenon, about 1/4 of patients with normal or decreased white blood cell count, leukopenia often It is a sign of poor prognosis, and patients often have anemia.

2. Sputum or bronchial smear and/or culture of Klebsiella pneumoniae is the basis for diagnosis, but it is affected by many factors.

(1) Under pathological conditions, the pharyngeal colonization rate of Klebsiella pneumoniae is very high, and it is easy to form specimen contamination of the oropharynx.

(2) The number of Klebsiella pneumoniae pneumonia is reduced, and mixed infections of various bacteria (especially in-hospital infections) are often unable to determine the main active bacteria.

At present, scholars at home and abroad believe that the sensitivity, specificity and reliability of sputum examination are not ideal. Many patients do not have much sputum, even if there are cockroaches, sometimes no bacteria can be found. Some patients can be determined through culture, but the initial diagnosis And treatment is not very helpful, but in terms of the current conditions and conditions of hospitals in China, smear gram staining and culture is still an important initial screening and diagnostic measures.

3. X-ray performance: large leaf consolidation, lobular infiltration, abscess formation, large leaf consolidation is located in the right upper lobe, due to the amount of inflammatory exudate, thick and heavy, so the interlobular fissure is curved, inflammatory infiltration See abscess, pleural effusion, a small number of bronchopneumonia.

Diagnosis and identification of Klebsiella pneumoniae pneumonia

diagnosis

Qualified sputum smears to find more Gram-negative bacilli, especially in the accumulation of pseudo-stratified ciliated columnar epithelial cells in the pus cells and bronchi with capsules, should consider the possibility of pneumonia bacilli pneumonia, but not diagnosed According to the sputum culture, the isolation of Klebsiella pneumoniae is conducive to diagnosis, but it should be differentiated from the contaminated bacteria colonized in the oropharynx. The sputum specimens screened by smear more than two times are separated into the concentration of K. pneumoniae by quantitative culture. >106 CFU/ml or semi-quantitative concentration is OR, can be diagnosed as pneumococcal pneumonia, for severe cases, refractory or immunosuppressed cases, using anti-pollution lower respiratory specimen sampling techniques such as truncated tracheal tracheal attraction (TTA), prevention Contaminated double-cannula brush sampling (PSB), bronchoalveolar lavage (BAL) and percutaneous lung puncture suction (LA), etc., the isolation of Klebsiella pneumoniae from these specimens can confirm the disease, pay attention to and actively carry out blood or chest Liquid bacterial culture, if positive, not only has a diagnostic significance, but also is important for selecting sensitive antibiotics and improving prognosis.

Differential diagnosis

Clinical should be differentiated from acute cheese pneumonia, bronchiectasis, pneumococcal pneumonia and so on.

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