OVERVIEW
Klebsiella pneumoniae, also known as Bacillus pneumoniae or Friedlander’s bacillus, is the first gram-negative bacillus recognized to cause pneumonia. Patients start suddenly with chills, high fever, cough, chest pain, purulent sputum, and characteristic brick-red jellied sputum. Some patients have gastrointestinal symptoms such as nausea, vomiting, diarrhea, and jaundice. Some patients are seen to have symptoms of upper respiratory tract infection. Very few patients present with a chronic course, which can also be prolonged from an acute course.
Etiology
Klebsiella pneumoniae is gram-negative, with pods, according to the different antigenic components of the pods, L. pneumophila can be subdivided into 75 subtypes, causing pneumonia to 1 to 6 types of the main, can quickly adapt to the host environment and long-term survival, and easy to produce resistance to a variety of antibiotics. Mostly seen in middle-aged and old age, any situation that leads to impaired immune function of the body can be a trigger for infection. Such as hormones and immunosuppressive drugs, as well as the use of antimetabolic drugs caused by systemic immune dysfunction and a variety of serious diseases; certain invasive examination, traumatic treatment and surgery, the use of contaminated respirators, nebulizers and so on may lead to the onset of infection. Hand-to-hand transmission by hospital staff, patients and chronic germ carriers are all sources of germs.
Symptoms
1. Symptoms
Sudden onset, chills, high fever, cough, purulent sputum, and brick-red jellied sputum are characteristic. Patients have chest pain. Some patients have gastrointestinal symptoms such as nausea, vomiting, diarrhea and jaundice. Generalized debility, some patients are seen to have symptoms of upper respiratory tract infection. Very few patients present with a chronic course, or it may be prolonged from an acute course.
2. Signs and symptoms
Acute appearance, dyspnea, cyanosis, jaundice and shock may occur in a few patients. Wet rales can be heard in the lungs.
Examination
1. Routine blood test
It shows that the white blood cell count is increased, the average range is (15～20)×109/L, in which there are toxic granules and left shift of the nucleus, about 1/4 of the patients have normal or decreased white blood cell count, decreased white blood cell count is often a sign of poor prognosis, and the patients are often combined with anemia.
2. Smear and/or culture of sputum or bronchial secretion.
The detection of Klebsiella pneumoniae is the basis for diagnosis.
(1) Pathologically, Klebsiella pneumoniae has a high rate of pharyngeal parasitization, which makes it easy to form oropharyngeal specimen contamination.
(2) Single Klebsiella pneumoniae pneumonia is decreasing and mixed infections with multiple organisms are increasing. It is often impossible to identify the main acting bacteria.
Diagnosis.
Middle-aged or elderly men, long-term alcoholism, chronic bronchitis or other lung diseases, diabetes mellitus, malignant tumors, organ transplantation or immunosuppression such as agranulocytosis, or patients with mechanical ventilation with artificial airways, presenting with fever, cough, sputum, dyspnea, and wet rales in the lungs, with an increase in blood neutrophils, and in combination with X-rays with inflammatory infiltrate manifestations of the lungs suggestive of bacterial pneumonia should be considered the disease Possible.
If more gram-negative bacilli are found in the smear of qualified sputum specimens, especially if they are heavily clustered around the pus cells and the pseudo-ciliated columnar epithelial cells of the bronchioles with podocytes, the possibility of Klebsiella pneumonia should be considered, but it is not the basis for the confirmation of the diagnosis. Isolation of Klebsiella pneumoniae on sputum culture facilitates the diagnosis, but should be differentiated from contaminating organisms colonizing the oropharynx. More than two consecutive isolations of Klebsiella pneumoniae from smear-screened sputum specimens or quantitative sputum culture isolation of Klebsiella pneumoniae at a concentration of >106 CFU/ml or a semi-quantitative concentration of ++++ or ++++ may be diagnostic of Klebsiella pneumoniae. In severe, refractory or immunosuppressed cases, the use of contamination-proof lower respiratory specimen sampling techniques such as transthoracic puncture tracheal aspiration (TTA), contamination-proof double-cannula brush sampling (PSB), bronchoalveolar lavage (BAL), and percutaneous lung aspiration (LA) can help to confirm the diagnosis of the disease.
Treatment
Treatment of Klebsiella pneumoniae pneumonia includes anti-infective therapy and supportive therapy. The effectiveness of anti-infective therapy directly affects the prognosis of the disease. With antibiotic treatment, the case fatality rate has been significantly reduced, but due to the high drug resistance rate of Klebsiella pneumoniae, the case fatality rate is 20% to 30%, which is still more than that of Streptococcus pneumoniae pneumoniae.
There are more drugs with antibacterial activity against Klebsiella pneumoniae, including first- to fourth-generation cephalosporins, broad-spectrum penicillins, aminoglycoside antibiotics, fluoroquinolones, carbapenems, and monocyclic β-lactams. With the expanding variety of clinically available drugs and the increasing number of multi-drug resistant strains, rational selection should be based on drug susceptibility testing. Second-, third- or fourth-generation cephalosporins or combined aminoglycosides are usually recommended, and cephalosporins alone can be used if drug sensitivity results are available. Alternatively, aztreonam and second-generation cephalosporins such as cefuroxime may be used. The new generation of broad-spectrum penicillins, such as piperacillin, have better therapeutic effects on Klebsiella pneumoniae pneumonia.
Aminoglycosides are available as amikacin. For pulmonary infections, especially severe infections, aminoglycosides are preferred in combination with β-lactams rather than alone. Fluoroquinolones such as ciprofloxacin and levofloxacin, cephalosporins such as cefoxitin and cefmetazole, and β-lactam/β-lactamase inhibitor combinations such as sultamicillin (ampicillin/sulbactam), cefoperazone/sulbactam, and piperacillin/clavulanic acid are also worthwhile because of their good antimicrobial activity against Klebsiella pneumoniae. In some areas, especially in hospital pneumonia, the detection rate of C. pneumoniae ultra broad-spectrum β-lactamase-producing (ESBL) strains has increased significantly, and for infections caused by such strains, carbapenems such as imipenem and meropenem are preferred. Cefoperazone/sulbactam also has good antibacterial activity against ESBL strains of Klebsiella pneumoniae. The course of anti-infective therapy for Klebsiella pneumoniae pneumonia is usually 10 to 14 days, or at least 3 weeks if the lesions are extensive, especially if multiple small abscesses are present. Supportive therapy, including maintaining airway patency, administering oxygen, correcting water, electrolyte and acid-base imbalances, and supplemental nutrition, should be emphasized in the treatment of Klebsiella pneumoniae pneumonia.
Prevention
1. Strict implementation of sterilization and isolation system
This is mainly for medical staff and hospital environment and equipment, strict hand washing and glove operation before and after contact with patients, regular environmental and indoor disinfection and ventilation, regular cleaning and disinfection of respiratory therapy devices according to requirements, regular replacement of mechanical ventilation and nebulizer tubing, etc., and the adoption of a complete set of rigorous nosocomial infection monitoring and prevention program. It has been reported that the rate of nosocomial infections is 20% lower in hospitals that have adopted this program compared to hospitals that have not.
2. Gastrointestinal Decontamination
This is a preventive measure commonly used in Europe, mainly for the susceptible population of nosocomial infections, aiming at removing the colonization and growth of colonies in the gastrointestinal tract. Methods include total gastrointestinal decontamination and selective gastrointestinal decontamination, commonly used for the latter, it is through nasal or oral gastrointestinal non-absorbable polymyxin B, tobramycin (gentamicin or neomycin, etc.) and dicentromycin B, used for 5 days, and the daily systematic application of cephalosporins, from the oropharynx and the gastrointestinal tract to remove the aerobic bacteria without lowering the number of anaerobic bacteria, the preventive effect of which is especially obvious in the case of gram-negative bacilli.
3. Protecting the acidic barrier of the stomach
Mainly in the prevention of stress ulcers, the application of aluminum thioglycollate drugs, which can prevent bleeding of stress ulcers, but also because it has the adsorption of gastric mucosa, change gastric mucus, increase the content of prostaglandin E2 (PGE2) in the lumen of the stomach, the absorption of pepsin, and does not change the acidic environment of the stomach, which can effectively play a role in preventing ulcers and preventing infections.
4.Bioprevention
Bioprophylaxis of Klebsiella pneumoniae is still in the experimental stage. However, mature vaccines and antibodies have not yet been applied to the clinic, and further research is needed.