Morganella pneumonia

Introduction to Morgan Bacterial Pneumonia Morgani pneumonia (Morganiipneumonia) is caused by infection with Morganella, and there is no report of this infection in China. In the past 10 years, the incidence of this infection has been reported to increase year by year, and it has become one of the common pathogens for hospital-acquired infections. basic knowledge The proportion of illness: the incidence rate is about 0.003%-0.007% Susceptible people: no special people Mode of infection: non-infectious Complications: pneumothorax

Cause of Morganella pneumonia

(1) Causes of the disease

Morganella, a genus of Enterobacteriaceae, was discovered by Morgan in 1906. It used to be called Proteus mirabilis. It is widely distributed in nature and is often found in the intestines of humans and animals. In recent years, with the development of biology Through its DNA research, it was found that the content of guanine and cytosine in Proteus mirabilis DNA molecules is significantly higher than that of other Proteus, so it has been separately isolated, called the genus Morganella, and now found: Morganella and Morganella biota.

1. Morphology and staining

Morganella is a non-proliferating single-celled organism. The Gram-negative blunt bacilli at both ends often have variants, sometimes spherical, sometimes long and curved or filamentous (10-30 m). It has no capsules and spores, is motivated, has round flagella and pili, and its blood coagulation and adsorption are not inhibited by mannose.

2. Culture and biochemical reactions

The Morganella is an aerobic or facultative anaerobic bacteria. The optimum growth temperature is 34-37 ° C. It can also develop between 10 and 45 ° C. It can be killed in 55 ° C water for 1 h. The culture requirements are not high. It grows well on common medium and can grow in potassium cyanide medium. The growth in the broth medium is evenly concentrated. The surface has a film. The colonies on the SS plate are round and flat. Translucent, easy to be confused with other intestinal pathogenic bacteria, the culture has a special odor, can hemolyze, can produce sputum, methyl red reaction positive, VP reaction negative, can quickly hydrolyze urea, does not form hydrogen sulfide, no Liquefied gelatin, no lysine decarboxylase and arginine double hydrolase, can produce ornithine decarboxylase and phenylalanine deaminase, not fermented lactose, sucrose, mannitol, euphorol, salicin, side Calendula alcohol, inositol, sorbitol, arabinose, raffinose and rhamnose, 80% of their strains produce gas when fermenting glucose.

3. Antigen and typing

There are 34 "O" groups and 25 "H" antigens in Morganella, which are grouped into bacterial antigens, and then divided into 66 serotypes by flagellation.

(two) pathogenesis

Morganella is a conditional pathogen and does not cause disease in the human intestine. When it leaves the intestine and enters the lungs, it can cause pneumonia. Its pathogenesis is related to its endotoxin and bacterial virulence. Animal experiments show that the mice are administered through the abdominal cavity. Injection of a virulent strain of 0.5 to 1.0 ml can kill the mouse. It is believed that the polysaccharide component may be the main component of its virulence. In addition, the Morganella can also secrete hemolysin, which has many cilia. The respiratory tract may also play an important role. The Morganella pneumonia is mostly hospital-acquired infection, and it is more common in the elderly. Any situation that can cause the body's immune function to be impaired may be the cause of infection. The original serious underlying diseases such as cancer, diabetes, etc. Long-term application of corticosteroids, immunosuppressive agents and cancer patients after chemotherapy and radiotherapy; some traumatic examinations and treatments, such as catheterization, venipuncture, joint puncture, major surgery, especially respiratory treatments such as endotracheal intubation, Tracheal incision, mechanical ventilation and aerosol inhalation, in addition, long-term application of broad-spectrum antibiotics can cause normal flora imbalance, which is beneficial to Morganella Respiratory tract colonization, when the body's resistance is reduced, it can enter the lower respiratory tract and cause disease, causing primary or secondary Morganella pneumonia. The pathological changes of Morganella pneumonia are lobes or segments, and alveolar tissue is destroyed. Small abscesses can also be changed by bronchial pneumonia.

Morganella pneumonia prevention

It is necessary to actively treat the primary disease and improve the body's resistance. All kinds of traumatic examination and treatment should be strictly aseptic, and patients should be actively treated and isolated to prevent cross-infection.

Morganella pneumonia complications Complications

Complications include pneumothorax and bleeding.

Symptoms of Morganella pneumonia Common symptoms Respiratory failure abscess snoring chills sepsis pleural effusion shortness of breath purulent sputum fever chills

Symptom

Similar to general acute bacterial pneumonia, such as fever, chills, chills, cough, sputum or sputum, chest pain, etc., but for the secondary pneumonia such as the original lung disease, the symptoms are not typical, can be expressed as respiratory failure , heart failure or primary disease symptoms, or high fever, increased cough, severe patients may have complication shock, sepsis and other complications.

2. Signs

Both lungs may have a wet voice, and when the inflammatory infiltration occurs in the lung segment or the leaf becomes solid, the tremor is enhanced in the corresponding lung segment.

Turbid, audible and bronchial breath sounds, some patients have shortness of breath, cyanosis, blood pressure drop.

Examination of Morganella pneumonia

1. routine inspection

(1) blood routine: peripheral blood like white blood cells and neutrophils increased.

(2) Gravel staining of sputum smear: A large number of Gram-negative bacilli were found.

(3) Blood gas analysis: PaO2 can be reduced in critically ill patients, and PaCO2 can be elevated in some patients with special chronic obstructive pulmonary disease, and there may be different degrees of acid-base imbalance.

(4) Blood biochemical examination: If there is liver and kidney damage during sepsis, transaminase, BUN and Cr may increase.

2. Pathogen examination

(1) Blood culture: In the case of bacillary pneumonia with bacteremia or sepsis, the blood culture has the growth of Morganella, and the blood-positive rate of blood-borne Morganella pneumonia is high. However, in recent years, it has been found that Morganella has antibiotics after application. L-type bacteria change, routine blood culture is negative, should pay attention.

(2) sputum culture: This method is simple and convenient, and the patient is easy to accept, but it is susceptible to bacterial contamination of the pharynx. It is generally considered that the sputum that is coughed out from the deep lungs of the patient should be taken and cultured after washing and homogenization quantitative examination. Greatly improve accuracy.

(3) Direct collection of lower respiratory secretions: This method is traumatic and requires certain conditions, but it is helpful for the diagnosis of Morgan's Morganella pneumonia, especially hospital-acquired pneumonia, because it avoids or reduces bacterial contamination of the upper respiratory tract. More accurate, clinically, according to the advantages and disadvantages of different methods, hospital equipment and doctors technical level, the following method is used to obtain lower respiratory secretions.

1 Circumcision puncture: Inserting a sterile plastic catheter to aspirate the lower respiratory secretions has the advantage of reducing pharyngeal bacterial contamination, but it is somewhat traumatic.

2 Under the chest X-ray positioning, the lung tissue and secretion culture of the pneumonia lesions were puncture through the chest wall, and the positive rate was high and the bacterial contamination of the upper respiratory tract was completely avoided, but the trauma was greater.

3 Lower respiratory secretions by fiberoptic bronchoscopy: This method is safer and can take specimens of the lesions under direct vision, but requires certain equipment.

(4) Other body fluid culture medium-stage urine bacterial culture count bone marrow bacteria culture pleural effusion, urine, bone marrow or wound secretion culture.

Morganella pneumonia, through the above-mentioned different methods of pathogen culture, can be found in Morganella, for mixed infections, especially secondary pneumonia, can also cultivate other Gram-positive or negative bacteria, while the culture-positive should be medicine Sensitivity test provides a basis for treatment.

Chest X-ray showed lung lobe, segmental dense shadow, consolidation, can form multiple lung abscess, some patients with bronchial pneumonia, generally less pleural effusion.

Diagnosis and identification of Morganella pneumonia

diagnosis

The diagnosis of Morgan's pneumonia should be based on clinical manifestations, chest X-ray and pathogen examination results, clinically, there are fever, chills, cough, cough and phlegm or phlegm, shortness of breath, chest pain, check the lungs and wet voices Chest radiograph showed double lung lobe, segmental infiltration shadow, or lung abscess formation, peripheral blood showed white blood cells and neutrophils increased, sputum smear Gram stained with a large number of negative bacilli, should consider the disease may be, for hospitals to obtain Pneumonia, due to the presence of primary disease, pneumonia symptoms are not typical, but if the following manifestations: sudden high fever on the basis of the primary disease; cough and cough increased; unexplained respiratory failure and heart failure; chest radiograph showed double lung infiltration shadow or based on the original lesion There is a new infiltrating lesion on the surface; combined with a large number of Gram-negative bacilli in the sputum, it should also consider the possibility of this disease, should be repeatedly checked, blood or direct lower respiratory secretion culture, where 2 or more times of sputum culture For the Morganella; or sputum and blood, or pleural effusion, the bacteria are cultivated; or the direct respiratory secretions are cultivated to produce the Morgania; or the sputum culture and the sputum are separated from the lungs. Combined with the above findings and chest X-ray results can be confirmed, but the primary or secondary Morgan pneumonia, sometimes difficult to distinguish clinically, is generally believed that Morgan infection wherever it occurs on the basis of primary pulmonary wait for secondary pneumonia.

Differential diagnosis

The clinical manifestations of pneumococcal pneumonia and chest radiographs are non-specific, similar to other Gram-negative bacilli pneumonia, clinically difficult to Klebsiella pneumonia, Pseudomonas aeruginosa pneumonia, Proteus pneumonia, Serratia pneumonia and tannic acid The difference between bacillary pneumonia is mainly due to sputum, blood or lower respiratory tract secretion pathogen examination. Therefore, those suspected of having bacterial infection of the lung should check the pathogen multiple times.

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