Serratia marcescens pneumonia

　　1. Morphology and staining:Serratia has motility and can move. Some strains have a capsule and flagella. Many strains produce pink or red pigments. Morphologically, mucoid Serratia marcescens is generally smaller than other enteric bacteria, without a capsule. It is a Gram-negative short rod, occasionally filamentous, with a size of (0.7～1.0)×0.7cm.

　　2. Culture and biochemical reactions:Serratia marcescens has low requirements for the growth medium. It can grow on nutrient agar, Yabuki agar, MacConkey agar, and blood agar plates. The colony of mucoid Serratia marcescens is round, slightly rough and sticky. The flagella are more likely to develop at temperatures below 37°C. It is an aerobic or facultative anaerobic bacterium. Serratia can ferment glucose, but only a few strains produce a small amount of gas. It does not ferment lactose, euonymose, arabinose, raffinose, and rhamnose, but can ferment mannitol, salicin, and sorbitol, and has inconsistent fermentation activity for resveratrol and inositol. It does not form indole, and most strains have a negative methyl red reaction and grow in potassium cyanide medium. Most strains quickly liquefy gelatin, while a few have a delayed reaction. It has lysine and ornithine decarboxylase. But it does not form arginine dihydrolase and phenylalanine deaminase, does not utilize sodium succinate, can utilize citrate, has a positive VP reaction, and produces acid but no gas on triple sugar iron medium (TSI). It can produce extracellular DNAase and lipase. Serratia produces a red pigment, which is often more abundant at temperatures below 37°C, but the ability to produce pigment decreases or even disappears after multiple passages. In 1902, Kroft extracted this pigment and named it 'prodigiosin', hence the mucoid Serratia marcescens was previously called Pseudomonas. It was not until 1960 that Rapoport and Hollen elucidated its chemical structure. Prodigiosin is soluble in alcohol, ether, chloroform, and other organic solvents but not in water. Prodigiosin is a lipopolysaccharide, and there are reports that it has the effect of increasing the number of white blood cells and anti-inflammatory. Both pigment-producing and pigment-non-producing strains can cause disease, and can cause sepsis, urinary and respiratory tract infections, osteomyelitis, and postoperative wound infections.

　　3. Antigen and typing:Serratia has somatic 'O' antigens and flagellar 'H' antigens. It is now known that there are 15 types of O and 13 types of H, totaling 46 serotypes.

　　4. Inducing factors:Serratia pneumoniae often occurs in hospitalized patients with pre-existing diseases. A11en et al. observed 135 cases of mucous Serratia infection at Temple University Hospital, 89% of which were related to reduced host resistance. Any condition that can damage the body's immune function may become a predisposing factor for infection, such as various serious diseases, malignant tumors, leukemia, diabetes, liver cirrhosis, heart failure, chronic bronchitis, pulmonary heart disease, uremia, and burns; long-term abuse of corticosteroids, immunosuppressants, and damage to the body's immune function; some invasive examinations and treatments, such as major surgery, indwelling urinary catheters, venous catheters, hemodialysis, and peritoneal dialysis; respiratory treatment measures, such as tracheal intubation, tracheotomy, mechanical ventilation, and nebulizer inhalation, can allow Serratia to be directly inhaled into the lungs. In addition, long-term use of broad-spectrum antibiotics and addiction to anesthetics makes Serratia more likely to colonize the respiratory tract, leading to the possibility of infection and disease, especially in newborns, the elderly, and pregnant women.

　　Commonly, it is septicemic pneumonia, and if not treated in time, complications such as sepsis, pleurisy, empyema, infectious shock, renal failure, and others may occur. At this time, the condition often worsens, with corresponding manifestations of complications; and severe cases may develop respiratory failure, heart failure, or sudden high fever with increased sputum production. Critically ill patients may have symptoms such as rapid breathing, cyanosis, and shock.

　　1. Symptoms

　　Similar to general acute bacterial pneumonia, the main manifestations are fever, chills, cough, expectoration of blood-stained or pseudo-blood-stained or yellow phlegm, dyspnea, chest pain. However, for patients with hospital-acquired infections or secondary Serratia pneumonia due to pre-existing lung diseases, the symptoms are atypical. The symptoms of the primary disease may mask the symptoms of pneumonia. At the same time, fever, cough, and expectoration of yellow phlegm may be symptoms of the primary disease, but at this time, patients often have a deterioration of their condition, and they may experience respiratory failure, heart failure, or sudden high fever with an increase in the amount of yellow sputum.

　　2. Signs

　　Dry and wet rales can be heard in both lungs. When a lobe or segment of the lung becomes solidified, there may be corresponding increased vibration, dullness, and bronchial breath sounds in the affected segment or lobe. Severe patients may have tachypnea, cyanosis, and shock.

　　Prevention:Actively treat the primary disease, enhance the body's resistance, strictly implement various disinfection systems and aseptic operations. Strengthen care for susceptible patients, isolate and treat patients with colonization and infection, prevent cross-infection, strictly control the indications for antibiotics and corticosteroids. Actively exercise, enhance physical fitness, prevent colds, eat less irritant food, pay attention to the combination of work and rest, maintain physical and mental health, which is also of great significance for the prevention of Serratia pneumonia.

　　First, Routine Examination

　　1. Peripheral blood picture shows an increase in white blood cells and neutrophils, and platelets may decrease.

　　2. Sputum examination by routine smear Gram staining, a large number of Gram-negative bacilli can be seen.

　　3. Severe cases often have hypoxemia, and some patients may have hypercapnia, with varying degrees of acid-base imbalance.

　　4. Some patients may develop renal failure, with increased BUN and Cr.

　　Second, Pathogenic Examination

　　1. Blood culture:Since Serratia pneumonia is often bacteremic, if blood culture is performed at the right time, the growth of Serratia can be detected, and the blood culture positivity rate for hemogenic Serratia pneumonia is generally high.

　　2. Sputum bacterial culture:This method is simple, convenient, and easy for patients to accept, but it is easily contaminated by respiratory tract pathogens. Therefore, the specimen should come from the deep lung, and it should be cleaned and homogenized before quantitative examination and sent for culture to improve accuracy.

　　3. Direct collection of lower respiratory tract secretion culture:Directly collecting lower respiratory tract secretions can reduce the contamination of the upper respiratory tract flora, resulting in more accurate results, but it is traumatic and requires certain conditions. Clinically, one of the following methods can be selected according to the advantages and disadvantages of various methods, hospital conditions, and the operator's technical level, especially for patients with hospital-acquired Serratia pneumonia, common examination methods include:

　　(1) Insert an aseptic thin plastic catheter through the thyrohyoid membrane, aspirate the lower respiratory tract secretions. Since it does not pass through the oral, nasal, and pharyngeal cavities, it reduces the contamination of bacteria in the throat, but it has a certain degree of trauma.

　　(2) Under X-ray chest fluoroscopy, aspiration of lung tissue and secretions from the shadow areas of lung inflammation infiltration through chest wall puncture completely avoids upper respiratory tract contamination, but it is more traumatic, and complications such as hemorrhage and pneumothorax can reach 20％.

　　(3) Sputum aspiration by fiberoptic bronchoscopy is a relatively safe examination method, but it requires certain equipment, and the operator must have a certain level of technical skills.

　　4. Other body fluid cultures:Midstream urine bacterial culture, bone marrow bacterial culture, and pleural effusion culture can detect the growth of Serratia.

　　After the above various body fluid cultures, positive results of Serratia can be obtained. To guide treatment, a drug sensitivity test should be added when the bacteria are isolated. For mixed infections, other bacteria can be isolated at the same time.

　　Thirdchest X-ray manifestations:Both lungs show increased pulmonary纹理, characterized by focal patchy bronchopneumonia, diffuse patchy infiltration in both lungs, mostly in the middle and lower lung fields, lobular or nodular pulmonary infiltration, consolidation of lung lobes or segments, with diameters

　　First, the therapeutic diet for Serratia pneumoniae pneumonia

　　1. Stir-fried Crucian Carp with Celery:Ingredients: 250 grams of crucian carp, 50 grams of fresh celery, starch, ginger strips, garlic strips, soy sauce, sugar, vinegar, monosodium glutamate, fine salt, wine, pickled chili, and vegetable oil. Preparation: Cut the crucian carp into strips, cut the celery into segments, and mix soy sauce, sugar, vinegar, monosodium glutamate, wine, salt, and starch with soup to make a sauce. Heat the wok over high heat, add oil, heat to 5成热, add the fish strips and stir-fry until separated, drain the excess oil, add ginger strips and pickled chili. Stir-fry the celery segments until fragrant, then add the sauce, add bright oil, and remove from heat. Benefits: Crucian carp has the effects of clearing heat and detoxifying, promoting diuresis and reducing swelling, stopping cough and expelling phlegm; celery has the effects of calming the liver and clearing heat, removing wind and promoting diuresis, and nourishing the mind and invigorating the body. Eating crucian carp and celery together is suitable for the auxiliary treatment of acute and chronic pneumonia.

　　2. Rabbit Meat and Mushroom Strips:Ingredients: 100 grams of cooked rabbit meat, 50 grams of mushrooms, 25 grams of scallion whites, appropriate amounts of chili oil, soy sauce, vinegar, sugar, sesame oil, sesame paste, Sichuan pepper powder, and monosodium glutamate. Preparation: Cut the cooked rabbit meat and scallion whites into thin strips, and cook the mushrooms. Place the scallion and mushrooms at the bottom, cover with rabbit strips, and serve in a dish. Dissolve the sesame paste in soy sauce in stages, mix the sesame oil evenly to make the sauce, and pour it over the rabbit strips. Benefits: Rabbit meat has the effects of clearing heat and detoxifying, benefiting the spleen and strengthening the body, removing dampness and cooling the blood, and promoting bowel movements; mushrooms have the effects of detoxifying and moistening, benefiting the spleen and strengthening the body, removing dampness and stopping diarrhea. Eating rabbit meat and mushrooms together is suitable for treating acute pneumonia.

　　3. Quail Lily Soup:One quail, 25 grams of lily, appropriate amounts of ginger, scallion, monosodium glutamate, and fine salt. Preparation: After the quail is killed, remove the feathers, feet, and internal organs, wash it clean, blanch it in boiling water, remove it and cut it into pieces; separate the lily petals, wash them, and set them aside. Wash the ginger and scallion, beat the ginger, and cut the scallion into segments. Place the pot on a high heat, add some water, add the quail, bring to a boil, add the lily petals, ginger pieces, and scallion segments, then simmer over low heat until the quail is cooked. Add salt and monosodium glutamate, simmer for several minutes, and then it can be served in a soup bowl. Benefits: Quail meat has the effects of benefiting the five internal organs, benefiting the liver and clearing the lungs, clearing heat and promoting diuresis, reducing accumulation and stopping diarrhea; lily has the effects of moistening the lungs and stopping cough, nourishing yin and clearing heat, and calming the mind. Both are suitable for acute and chronic pneumonia.

　　4. Lean meat and cabbage soup:Ingredients: lean meat, 100 grams of cabbage heart, a little ginger, garlic, salt, monosodium glutamate, and chicken oil. Preparation: slice the lean meat, wash and slice the cabbage, put it in boiling water, remove it when it is just cooked, rinse it in clean water, drain the water and set aside; place the pot on a high heat, add chicken oil and heat to 50%, add garlic and stir-fry until golden brown, then add the lean meat and stir-fry together, add fine salt, add soup to cook, then add the cabbage heart and bring to a boil, add monosodium glutamate and it is ready to eat. Benefits: lean meat has the effects of invigorating the middle, nourishing the Qi, moistening the intestines; cabbage is mild in nature and sweet in taste, with the effects of clearing heat and detoxifying, resolving phlegm and stopping cough, relieving irritability and promoting defecation. The combination of lean meat and cabbage is suitable for acute and chronic pneumonia.

　　Second, what foods are good for the body with Serratia pneumonia?

　　1. Foods should be high in nutrition, light, and easy to digest, preferably in a liquid form, especially juice.

　　2. Fresh fruits and vegetables.

　　3. Foods with high oil content, eggs, and other foods rich in vitamin A.

　　Third, what foods should be avoided for Serratia pneumonia?

　　1. Avoid spicy and greasy foods. Do not eat large fish, meat, and overly greasy products. Pneumonia patients should not add spices such as chili, pepper, mustard, Sichuan pepper, etc. to their diet. Quit smoking and drinking.

　　2. Avoid sweet and warm fruits, such as peaches, apricots, plums, and oranges.

　　3. Avoid cold and raw foods: Various ice drinks; fruits and vegetables with cold properties, including watermelons, pears, bananas, kiwis, etc.; secondly, avoid foods with sour taste: such as vinegar, sauerkraut, pickled vegetables, and hawthorn, black plums, sour tangerines, etc.; astringent foods: such as white fungus, lotus root nodes, and unripe persimmons, crabapples, etc.

　　(The above information is for reference only. For details, please consult a doctor.)

　　1. Treatment Principles:Use sensitive antibiotics to promote sputum drainage, keep the respiratory tract unobstructed, correct hypoxia, protect heart, kidney, and liver function, strengthen nutritional support, and treat the primary disease and complications.

　　2. Prognosis:The prognosis of this disease is poor. The following manifestations suggest a poor prognosis: age over 75, platelet count ≤ 100,000, shock, elevated bilirubin, accompanied by other Gram-positive or Gram-negative mixed infections.