Citrobacter pneumonia

Introduction to Citrobacter pneumonia Citrobacter pneumonia is caused by infection with C. citrate and is a common acquired infection in hospitals. In recent years, the incidence rate has increased, and the bacteria are resistant to a variety of antibiotics, the treatment is difficult, and the prognosis is poor. basic knowledge The proportion of sickness: 0.0012% - 0.0015% Susceptible people: no specific population Mode of infection: non-infectious Complications: septic shock respiratory failure myocarditis endocarditis lung abscess

Cause of pneumococcal pneumonia

(1) Causes of the disease

Citrobacter is a genus of Enterobacter genus, which was first described by Werkman and Gillen in 1932. It consists of three species, namely, bacterium, bacterium, and bismuth malonate. Citrobacteramalonaticus, found in 1979, has no biotype of C. malonate, which is called citrobacter amalonaticus biogrouPI, and is associated with human diseases.

Culture and biochemical reactions (25%):

Citrobacter faecalis grows in simmons citrate medium, can grow in medium containing KCN (potassium cyanide), grows acid in jordoni tartrate medium, and can be produced by F. fuligis Hydrogen sulfide, citrate can ferment glucose, mannitol, usually gas, in addition, fermented sorbitol, arabinose, rhamnose, maltose, xylose, sucrose, cellobiose and glycerol, reducing nitrate , does not ferment pentaerythritol and inositol, fermenting ability of lactose, sucrose and salicylic acid are inconsistent between the strains, can not deamination of lysine and phenylalanine, no DNase, no liquefied gelatin, most strains can The urease was slowly produced, the sputum reaction was negative, the MR (methyl red) reaction was positive, the VP reaction was negative, and the nitrogalactose (Onitrophenyl--D-galactoside) galactosidase (ONPG) test was positive.

Antigen and isolation (20%):

The characteristics of C. citrate are similar to those of Salmonella, some of which have Vi antigen and are called salmonell balIerup. The main members of this strain were once known as Bessa. Salmonella bethesda-ballerup, which is a strain of the genus Escherichia (E. faecalis), studied by the Besadda-Balerupella flora, 32 "O" groups and 75 "H" antigens were established. Later, Sedlak and Slajsova discovered 10 new "O" groups, some of which were originally classified as Escherichia coli. Currently there are about 40 or more. The "O" group, the "O" antigen of this group of strains has cross-antigenicity with some "O" groups of Salmonella and Escherichia.

Morphology and staining (10%):

Citrobacter bacillus is aerobic or facultative anaerobic bacilli that are motivated, have no spores, and are negative for Gram staining.

(two) pathogenesis

The pathogenicity of C. citrate is not certain. It is believed that the pathogenicity of the bacterium is weak, and some strains are considered to have strong virulence. The animal model has found that the virulence of C. faecalis causing human meningitis Significantly larger than the strain that does not cause meningitis, and the strain causing human meningitis has outer membrane protein, while the acidophilic endotoxin produces endotoxin, which are related to the pathogenesis, in addition, the pathogenicity of the bacillus acidophilus and the host Status, ciliary movement and clearance, tracheal intubation, tracheotomy, fiberoptic bronchoscopy, airway suction, oxygen inhalation, mechanical ventilation and aerosol inhalation, etc., which are beneficial to the sputum bacillus in the upper respiratory tract Colonization, or direct inhalation into the lungs, or blood-borne dissemination to the lungs, causing primary citrate pneumonia or secondary citrate pneumonia, pathological changes mainly manifested as bronchial pneumonia, may have alveolar wall destruction Small abscesses and focal bleeding are formed.

Citrobacter pneumonia prevention

The treatment of this disease is more difficult, so prevention is very important, it should improve the body's resistance, prevent the occurrence of citrate pneumonia, to actively treat the primary disease; correct control of antibiotics, glucocorticoid use indications; keep the air in the ward fresh and clean, Especially for intensive care units, neonatal rooms, geriatric wards and other susceptible wards, such as tumor chemotherapy and radiotherapy patients, kidney transplant patients, etc., should be regularly irradiated with ultraviolet light, floor wet wipe disinfectant; various diagnosis and treatment Operation, especially respiratory therapy equipment should be strictly sterile disinfection system; timely treatment of patients to strengthen care to prevent cross-infection.

Citrobacter pneumonia pneumonia Complications septic shock respiratory failure myocarditis endocarditis lung abscess

Severe citrate pneumonia can cause the following complications due to bacteremia or sepsis: septic shock, respiratory failure, acute myocarditis, endocarditis, toxic hepatitis, acute renal failure, lung abscess, empyema, whole body Multiple abscesses, DIC, etc., at this time may have the symptoms and signs of the corresponding damaged organs, while the condition deteriorates, the mortality rate increases significantly, and the prognosis is poor.

Symptoms of citrate pneumonia common symptoms chills, high fever, dyspnea, shortness of breath, chest pain, blood pressure, jaundice, respiratory failure, diarrhea, abdominal pain

Symptom

Pythium citrate pneumonia is mostly hospital-acquired pneumonia. It is reported that 75% of patients have primary disease, especially in hematological malignancies, and socially acquired (out-of-hospital) pneumonia is rare. For no primary pulmonary infection. The clinical manifestations of P. citrate pneumonia are similar to those of general acute bacterial pneumonia. The main symptoms are chills, fever, cough, phlegm or phlegm, chest pain, difficulty breathing, and some patients may have abdominal pain. Diarrhea and other gastrointestinal symptoms, because citrate pneumonia can be bacteremia or septic pneumonia, when the symptoms of systemic poisoning are more obvious, but for the original chronic obstructive pulmonary disease and other secondary citrate pneumonia, the symptoms are not Typically, the symptoms of pneumonia can be masked by the presence of the primary disease. Patients can show high fever, increased cough and jaundice, respiratory failure, heart failure, or exacerbation of the original condition. Some patients have a critically ill condition and can have no pneumonia until The post-mortem autopsy was confirmed.

2. Signs

Pythium citrate pneumonia can have a thickened breath sound, one or both sides of the lower lung wet voice, when the lung leaves appear, the segment can be in the corresponding lung lobe, the segment appears tremor, turbid, bronchial breath sounds Or wet voice, if there is pleural effusion, there may be effusion side tremor and breath sounds are weakened, in addition some patients may have shortness of breath, cyanosis, blood pressure drop, jaundice and so on.

Examination of bacillus pneumonia

1. routine inspection

(1) Blood routine: Peripheral blood leukocytes and neutrophils can be increased, but severe patients can be reduced.

(2) Gradient staining of conventional sputum smear: A large number of Gram-negative bacilli can be found.

(3) Arterial blood gas analysis: PaO2 can be decreased in severe patients, some patients may be accompanied by elevated PaCO2, and may have different degrees of acid-base imbalance.

(4) blood biochemical examination: some patients may have urea nitrogen, creatinine, transaminase, elevated bilirubin and so on.

2. Pathogen examination

(1) Blood culture: The bacillus pneumonia pneumonia is more positive in blood culture when there is bacteremia. Generally, the blood culture positive rate of blood-borne bacillus pneumonia is higher, and sometimes the blood culture is negative and the bone marrow culture is positive.

(2) sputum culture: This method is simple and convenient, and the patient is easy to accept, but it is susceptible to the contamination of the upper respiratory tract colony and affects the accuracy of the result. Therefore, it is required to select the patient to clean the sputum with 3% hydrogen peroxide and then the deep lung. Coughing out the sputum, and sputum washing and homogenization quantitative examination after culture, can greatly improve the positive rate and diagnostic accuracy.

(3) Direct collection of lower respiratory secretions culture: avoids bacterial contamination of the upper respiratory tract, which is more accurate, but has certain traumatic nature. It can be selected according to the advantages and disadvantages of various methods, hospital conditions and doctors' technical level to improve pathogens. The diagnostic rate, especially for hospital-acquired citrate pneumonia, should be used to send lower respiratory secretion cultures using the following methods.

1 through the ring-shaped membrane puncture inserted into the thin plastic catheter to aspirate the lower respiratory tract secretion, the advantage is that no oral, nasal, pharyngeal cavity, reduce pollution, but there is a certain trauma, puncture may be subcutaneous emphysema, bleeding and so on.

2 Under the chest X-ray positioning, the lung tissue and secretions of the lesion site are puncture through the chest wall. The advantage is that the secretion of upper respiratory tract secretion is completely avoided. The disadvantage is that the trauma is large, and complications such as pneumothorax can be as high as 20%. However, the detection rate of bacteria was 84%.

3 Lower respiratory secretions by fiberoptic bronchoscopy: A. Direct aspiration and secretion culture by fiberoptic bronchoscopy; B. Quantitative culture of bronchoalveolar lavage fluid by fiberoptic bronchoscopy, sensitivity and specificity are 90% and 97, respectively %, the sensitivity and specificity of those who have received antibiotic treatment are 78% and 96%, respectively; C. Bronchoalveolar lavage culture through fiberoptic bronchoscopy; D. Fiberoptic bronchoscopy with double-tube specimens, sampling and culture It can prevent the specimen from being contaminated; E. Under the chest X-ray positioning, the fiberoptic bronchoscopy lung biopsy can be used for diagnosis and differential diagnosis, but it is traumatic.

(4) Other body fluid culture: such as pleural effusion, cerebrospinal fluid, urine, etc.

After the above method, the positive result of C. citrate can be obtained. For the guidance treatment, the drug susceptibility test should be added at the same time. In addition, some secondary citrate bacilli pneumonia, in addition to the culture of C. citrate, Other Gram-negative or positive bacteria grow.

X-ray performance: The chest X-ray of Pythium citrate pneumonia is mainly characterized by bronchial pneumonia, which can be a focal wet shadow or a diffuse bilateral inferior lung infiltration shadow, small pulmonary abscess, pleural effusion and empyema are less common.

Diagnosis and identification of citrate pneumonia

Salmonella pneumonia

The performance of bacillus fuliginea bacteremia can be similar to the clinical manifestations of typhoid fever, and Salmonella can also cause pneumonia, both of which can be positive for fatdasis. Therefore, clinical attention should be paid to the difference between the two, caused by Salmonella. Pneumonia is very atypical, similar to citrate bacilli pneumonia, such as chills, fever, cough, cough, snoring and wet voices in the lungs, chest radiographs, segmental pneumonia or pulmonary abscess Formation, clinically difficult to identify, but sputum, pleural effusion, blood or size can be cultured Salmonella, fat response "O" more than 4 times and so on can be identified with citrate pneumonia.

2. Other Gram-negative bacilli

P. citrate pneumonia and Klebsiella pneumoniae, Pseudomonas aeruginosa pneumonia, Proteus pneumonia, Serratia pneumonia and Morgan Morgan pneumonia are similar, especially in hospital-acquired infections, Klebsiella The typical manifestations of pneumonia are red brick-like mites, and the yellow-green sputum of Pseudomonas aeruginosa pneumonia is lacking. Therefore, the identification is mainly based on bacteriological examination of blood, sputum, pleural effusion and lower respiratory secretions. Sometimes there are mixed infections between them. In particular, those with secondary citrate pneumonia should be noted.

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