Klebsiella infection

Introduction to Klebsiella infection Klebsiella is found in the intestines and respiratory tract of normal people and is also found in water and grains. People with low immunity and those undergoing surgical and invasive iatrogenic procedures are susceptible to bacterial infections and are common pathogens of community-acquired pneumonia and hospital-acquired pneumonia. basic knowledge The proportion of sickness: 0.2% Susceptible people: good for middle-aged men Mode of transmission: iatrogenic transmission Complications: pneumonia, lung abscess, bronchitis

The cause of Klebsiella infection

Cause:

Klebsiella is currently the most important pathogen in addition to E. coli. It is similar to the biochemical reaction of Serratia, Enterobacter and Hafnia. Some amino acid decarboxylase tests are helpful for identification. Klebsiella can be divided into five species, namely K. pneumoniae, R. oxytoca, K. ornithinolytica, vegetative K. planticola and K. terrigena, of which Klebsiella pneumoniae can be divided into three subspecies: subsp. pneumoniae, subspecies of stinky nose ( Subsp.ozaenae) and subsp. rhinoscleromatis, in clinically isolated Klebsiella, Klebsiella pneumoniae accounted for more than 80%, is the most important and common pathogen in this genus, the bacteria It is a short bacillus with a length of 1 to 2 m and a width of 0.5 to 0.8 m. It can produce capsules, no spores, no motility, and often end-to-end paired development. The capsule is a chlorine-free polysaccharide material, thicker, and leather. Blue staining can be observed, but it is easier to observe by Indian ink staining method. The optimal growth temperature of this strain is 37 °C. It can be grown in the range of 12 to 43 ° C, and can be inactivated at 55 ° C for 30 min.

In the identification medium, the existing color colonies are fermented by the lactose, and on the solid medium, the colony can be grayish-white sticky-like colonies due to the production of a large amount of capsular material, and the colonies are easily fused to each other, and the inoculation ring is easy to pull into a silk; After culturing for several days in the broth, the liquid is obviously viscous. Klebsiella has a bacterial antigen O and a capsular antigen K. According to the composition of the capsular antigen K, Klebsiella pneumoniae can be divided into 80 types, and most of the pneumonia subspecies. It belongs to capsule type 3 and 12; the subspecies of 4,5,6,15 are the most common type; the subtype of nasal induration is mostly type 3, and the virulence of Klebsiella is very strong. Klebsiella pneumoniae (100 bacteria) can cause death in mice by injecting into the peritoneal cavity of mice. This strain is highly adaptable and can quickly adapt to the host environment to survive. It is easy to produce resistance to various antibiotics. One of the bacteria with the highest rate of broad-spectrum -lactamase is often resistant to multiple antibiotics. This resistance can be chromosomally mediated and can also cause infection in certain hospital wards through the spread of drug-resistant plasmids. popular.

Pathogenesis

Pneumonia caused by Klebsiella can be divided into primary pneumonia and secondary pneumonia. The boundary between the two is sometimes difficult to distinguish. It is generally believed that on the basis of the original pulmonary infectious disease, it occurs under certain pathogenic conditions. The infection of this bacterium is secondary. The virulence of Klebsiella may be related to its capsule. The capsule can inhibit the chemotaxis and phagocytosis of macrophages, but the exact pathogenesis has not been fully elucidated. The pathological feature is that the bacteria grow and multiply quickly, and single or multiple abscesses can be formed in each organ. The exudate contains a large number of gram-negative bacilli with capsular membrane, and primary lobar pneumonia caused by Klebsiella pneumoniae. In elderly patients, alcoholism, and patients with severe primary diseases such as diabetes, cancer, and blood diseases, the pathological changes are different from those caused by pneumococcal disease. The alveolar wall is often necrotic and liquefied to form single or multiple abscesses. The alveoli contain a large amount of bloody sticky sputum. The surface of the abscess is covered with fibrin exudate. The pleural adhesion is prone to occur in the early stage. The incidence of empyema is about 25%, which is higher than pneumococcal pneumonia. The lesion dissipates. Incomplete, causing fibrosis, residual suppurative lesions or bronchiectasis, Klebsiella pneumoniae infection accounts for 10% of hospital infections, such as urinary tract infections, respiratory tract and wound infections, liver and kidney in cases of sepsis Brain and other multiple suppurative lesions and chest cavity, pericardial empyema, etc., lesions in the colon can still cause pseudomembranous colitis, occasionally can cause perforation and diffuse peritonitis, hard-nosed subspecies and subspecies The pathogenicity has not yet been fully elucidated. The former can cause chronic granulomatous induration. The latter may be related to the nasal sinus caused by atrophy of the nasal mucosa and turbinate. It is an opportunistic infection.

Klebsiella infection prevention

Improve human immunity, especially for patients undergoing surgery and invasive iatrogenic operations, medical equipment, ventilators, various types of intubation, etc. should be strictly disinfected, operating specifications, to prevent iatrogenic or opportunistic infections, Drug-resistant Klebsiella pneumoniae is easily transmitted between Gram-negative bacilli of the same species or different species. Once ESBLs-resistant strains are found, effective measures should be taken in time, including isolation of infected persons, and prevention of drug-resistant strains in hospitals. Spread in the intensive care unit. Strengthen nutrition and use foods that are easy to digest, contain enough calories, protein and vitamins. Such as porridge, milk, soft rice, soy milk, eggs, lean meat, fresh vegetables and fruits rich in vitamins A, B, C. These foods can enhance the body's resistance.

Klebsiella infection complications Complications, pneumonia, lung abscess, bronchitis

Concurrent bronchitis, pneumonia, lung abscess, pus and so on.

Klebsiella infection symptoms common symptoms dyspnea abdominal infection skin soft tissue infection lung infection chest pain high heat chills chills acute face relaxation heat rust color

1. Respiratory infections Klebsiella pneumoniae is one of the most common pathogens of respiratory infections. It ranks second among Gram-negative bacilli in sputum specimens, second only to Pseudomonas aeruginosa, and some of the foreign reports are the first. Cross-infection in hospitals often leads to bacterial colonization in the pharynx, followed by bronchitis or pneumonia, long-term hospitalization, application of antibacterial drugs, etc., causing pharyngeal bacillus bacteria to cause bronchial and pulmonary infections, caused by Klebsiella pneumoniae Acute pneumonia is similar to pneumococcal pneumonia, with acute onset, often with chills, high fever, chest pain, sputum thick and not easy to cough up, sputum brick red or dark brown (25% to 50%), but also blood stasis And rust color sputum, some patients have obvious hemoptysis, physical examination can be found in patients with acute face, difficulty breathing, cyanosis, a small number of patients may have jaundice, shock, 2 / 3 patients with body temperature between 39 ~ 40 ° C, herpes labesorrhea is not common, lung There are signs of consolidation, wet voice, X-ray changes, there may be large leaf consolidation, lobular infiltration and abscess performance, large leaf consolidation is mostly located in the upper lobe, due to inflammation and exudate, thick and sticky, so Interruption often falls in a curved shape, inflammatory infiltration is thicker than other pneumonia, sharp borders, 16% to 50% of patients have lung abscess formation, a small number of bronchial pneumonia or bilateral lung infiltration, and sometimes can also be bilateral hilar Infiltration, the system often has systemic failure in the early stage of the disease, the prognosis is poor, the mortality rate is about 50%, and the prognosis is worse in patients with extensive lung gangrene. Klebsiella pneumoniae pneumonia can be a chronic disease course, and can also be extended from chronic to chronic. It is a clinical manifestation of lung abscess, bronchiectasis and pulmonary fibrosis.

2. Septicemia Reported that Klebsiella pneumoniae septicemia accounts for the second place in Gram-negative bacilli sepsis, second only to E. coli, the vast majority of patients have primary disease and/or have used broad-spectrum antibiotics, immune The most common cause of inhibitors or antimetabolites is surgery. The invasive route includes respiratory tract, urinary tract, intestine, abdominal cavity, intravenous injection and neonatal umbilical cord. The intravenous infusion of bacteria can cause local epidemics. Dangerous, in addition to fever, chills, sometimes accompanied by shock, jaundice, fever is more relaxation heat, can also be bimodal fever, migratory lesions can be found in the liver, kidney, lung, bones, armpits, meninges and Brain parenchyma, etc., the mortality rate is 30% to 50%.

3. Suppurative meningitis Klebsiella pneumoniae caused by suppurative meningitis increased daily, in the Gram-negative bacterial meningitis, the second, more common in brain trauma or brain surgery, neonatal can also occur, prognosis Very poor, insidious onset, often fever, headache, neck and other meningitis symptoms and signs, can appear intracranial hypertension symptoms, increased white blood cells and neutrophils in the cerebrospinal fluid, increased protein, decreased sugar and chloride, The smear can be found in the gram-negative Gram-negative bacilli. The positive culture can establish a diagnosis. The elderly patients often have sepsis and the mortality rate is high.

4. Urinary tract infections It is reported that Klebsiella pneumoniae is the third cause of urinary tract infection. Most patients have primary diseases such as bladder cancer, prostatic hypertrophy, bladder weakness, urethral stricture, etc., which can also occur in malignant Tumors or other patients with severe systemic diseases, catheterization, indwelling catheter or urinary tract examination are common causes. The short-term effect is better after treatment with appropriate antibiotics, and the clinical manifestations are the same as those caused by other pathogens. .

5. Others such as wound infection or other wound infection after surgery, skin and soft tissue infection, abdominal infection, endocarditis, osteomyelitis, arthritis, etc., can be caused by Klebsiella, the clinical manifestations are similar to those caused by other bacteria It is easier to form an abscess. Klebsiella pneumoniae nasal induration can cause chronic granulomatous induration, most commonly involving the nasal cavity, sinus, throat, trachea and bronchus. Its histological necrosis and fibrous tissue Hyperplasia, visible foamy cells containing Gram-negative bacilli (so-called Mikulicz cells), Klebsiella pneumoniae subspecies (commonly known as Rhizoctonia solani) can cause nasal mucosa and turbinate atrophy Unlike induration, stinky nose is not a primary bacterial infection, and there may be other factors involved in its onset.

Examination of Klebsiella infection

Leukocytes and neutrophils, new infiltrative lesions appear on X-ray films, and patients with ineffective penicillin should consider this disease, 2 or more times of sputum culture positive, or pleural effusion, blood culture positive can be diagnosed, In most patients with sepsis, the total number of white blood cells is significantly increased, and neutrophils are increased. However, the number of white blood cells in patients with hematological diseases or anti-metabolites may not increase, or may be reduced. Others such as urine and cerebrospinal fluid in patients with urinary tract infections and meningitis. There are corresponding changes.

A new infiltrating lesion appears on the chest X-ray.

Diagnosis and identification of Klebsiella infection

diagnosis

Typical Klebsiella pneumoniae pneumonia often occurs in middle-aged and elderly men. Patients with chronic bronchopulmonary disease who have been drinking alcohol for a long time have typical clinical manifestations and X-ray signs. Combined with sputum culture results, it is not difficult to diagnose, but there are serious primary diseases. On the basis of the onset, the clinical manifestations are atypical, the diagnosis is more difficult, in the process of the original disease, high fever, white blood cells and neutrophils, new infiltrative lesions appear on the chest X-ray, and penicillin treatment should be considered The disease, 2 or more consecutive sputum culture positive, or pleural effusion, blood culture positive can be diagnosed, the majority of septic patients have a significant increase in the total number of white blood cells, neutrophils increased. However, the number of white blood cells in patients with blood diseases or anti-metabolites may not increase, or vice versa. Others such as urinary tract infections and meningitis have changes in urine and cerebrospinal fluid. The diagnosis should be based on bacterial culture results. Caused by chronic granulomatous induration, Mikulicz cells were found to have a definite value in biopsy.

Differential diagnosis

Clinical attention should be paid to the identification of Streptococcus pneumoniae infection.

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