Pseudomonas aeruginosa meningitis

Introduction

Introduction to Pseudomonas aeruginosa meningitis Pseudomonas aeruginosa is a major species in the genus Pseudomonas and is the main pathogen causing various infections in the clinic. It accounts for 5% to 15% of all iatrogenic infections. Cytobacteria are widely distributed in nature and are one of the most common bacteria found in the soil. The bacteria are present in the skin, intestines and respiratory tract of normal people. Pseudomonas aeruginosa is an opportunistic pathogen and is one of the main pathogens in hospital infection. Pseudomonas aeruginosa meningitis often occurs in open brain injury, after brain surgery, or because of lumbar puncture and waist. Caused by poor disinfection or equipment contamination: wound infection in patients with extensive burns, serious underlying diseases such as tumors, blood diseases, immunodeficiency diseases, diabetes, etc., as well as the use of antibiotics, adrenocortical hormones and other drugs and indwelling catheters such as Cardiac catheters, catheters, etc., can cause Pseudomonas aeruginosa sepsis, which in turn causes meningitis. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: septic shock coma

Cause

Causes of Pseudomonas aeruginosa meningitis

Bacterial infection (55%):

Pseudomonas aeruginosa can form green pus on agar plates or infected wounds, Gram-negative bacteria without spores, in different shapes, arranged in pairs or short chains, although aerobic bacteria, can also be Growth under anaerobic conditions, the most suitable growth temperature is 35 ° C, can still grow at 42 ° C, according to which can be identified with Pseudomonas fluorescens, the bacteria are not high nutritional requirements, often accompanied by grape odor It is emitted by trimethylamine.

Antigen factor (25%):

The bacterial O antigen has two components, one is endotoxin protein, which is a protective antigen, and the other is lipopolysaccharide, which is type-specific. According to its structure, Pseudomonas aeruginosa can be divided into 12 serums. Type, in addition to phage or pyocyanin for typing.

Environmental factors (20%):

Pseudomonas aeruginosa has strong resistance to the outside world, can survive for a long time in the wet place, is not sensitive to ultraviolet rays, can tolerate a variety of disinfectants, and is resistant to many kinds of antibiotics. It can be used in humid heat at 55 ° C for 1 h. Inactivated.

Pathogenesis

Endotoxin of Pseudomonas aeruginosa can cause fever, shock and acute respiratory distress syndrome, etc. Exotoxin A is a lethal factor for animal death, which can cleave nicotinamide adenine dinucleotide (NAD) smoke. The amide moiety catalyzes the covalent attachment of adenosine diphosphate ribose to EF-2, leading to blockade of the ribosome code movement process, thereby preventing cellular protein synthesis, necrosis of tissue, causing local or systemic disease processes, and body-to-copper green The immunity of the bacterium is mainly humoral immunity. The specific antibodies are mainly IgG and IgM, among which IgM is the strongest, IgG, IgM, complement, properdin, etc. assist neutrophils and mononuclear-macrophages, phagocytosis and Killing Pseudomonas aeruginosa, it is not easy to cause disease, but if it changes or damages the normal defense function of the host, or the immune function is defective, it can often develop from infection to infection in the hospital environment, the pathology of Pseudomonas aeruginosa meningitis. Changes, early pia mater and superficial vascular congestion, expansion, inflammation along the subarachnoid space, a large number of purulent exudate covering the surface of the brain, often deposited in the sulci and brain basal cistern, etc. It can be seen in the ventricle, and the color of cerebrospinal fluid is grass green. With the expansion of inflammation, the superficial pia mater and ependymal membrane are covered by fibrin exudate, and the cerebrospinal fluid is absorbed and circulatory disorder due to meningeal adhesion in the later stage of the disease. , causing traffic or non-communicating water.

Prevention

Pseudomonas aeruginosa meningitis prevention

Pseudomonas aeruginosa is widely found in nature, and it is easy to contaminate drugs, equipment, etc. It can become a pathogen of iatrogenic infection through various routes of transmission. Therefore, it is necessary to strictly implement the disinfection and isolation system to prevent cross-infection in hospitals. Prevention is still under investigation and its exact effect is still being further observed.

Complication

Complications of Pseudomonas aeruginosa meningitis Complications , septic shock, coma

Increased intracranial pressure, septic shock, coma.

Symptom

Pseudomonas aeruginosa meningitis symptoms common symptoms immunodeficiency high fever does not retreat neck tonic heat retention hyperthermia meningitis cold war toxemia coma increased intracranial pressure

When accompanied by sepsis, the patient has high fever, chills, chills, accompanied by headaches, loss of appetite and apathy and other toxic symptoms, common mental symptoms, excitement, confusion, fever, fever often relax or heat retention, often Accompanied by shock, the skin appears gangrenous deep pusis as its characteristic manifestation, the surrounding ring is erythema, 48 to 72 hours after the appearance of rash, the center is grayish black gangrene or ulcer, the patient has high fever and toxemia persists, central nervous system Symptoms of the system are aggravated, meningeal irritation occurs, due to increased intracranial pressure, frequent vomiting, increased blood pressure and slowed pulse, high incidence of septic shock and coma, especially in patients with immunodeficiency or tumors In patients, the onset is slow, sometimes it can hide the onset, lack of systemic symptoms and signs.

Examine

Examination of Pseudomonas aeruginosa meningitis

Take specimens of infected parts, such as pus, sputum, blood, urine, rash, puncture or exudate, etc., and identify them according to the characteristics of microorganisms. Diagnosis can be established. Green pus and cerebrospinal fluid can be directly smeared first. Or after centrifugation, the precipitate smear is stained. If it is a Gram-negative bacteria, the clinical manifestation can be clearly diagnosed, culture-positive, and biochemically identified as Pseudomonas can be diagnosed, and the green pus can be produced on the selection medium. The pigment can be identified as Pseudomonas aeruginosa. If there is no pigment or Gram-negative bacilli which do not ferment lactose or glucose on the identification medium, the following methods can be further identified.

Pigment identification

Bacteria can be inoculated on King A, King B slant medium for 24 hours at 37 ° C or at room temperature for 5 days.

(1) P. aerugin pigment: dark green on the slope of King A, green in liquid medium contact with air, if the pigment is not obvious or mixed with other pigments, add chloroform to the slope, and observe at room temperature for 1 to 24 hours, if still not Obviously, dilute hydrochloric acid can be added dropwise to the chloroform solution, and the pus pigment is red in the acid layer.

(2) Pseudomonas fluorescein: Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas putida showed yellow-green fluorescence on King B slant medium.

(3) red pus pigment: reddish purple on King A slant medium, such as 37 ° C 24h red is not obvious, can be set at room temperature for 3 to 5 days to observe, Pseudomonas aeruginosa produces less red venom see.

(4) Black septic toxin: Pseudomonas aeruginosa often produces black pus toxin in cattle containing peptone medium, and black pus toxin is also produced in Stenotrophomonas maltophilia.

2. Other identification

The main identification of Pseudomonas aeruginosa and other Pseudomonas is glucose oxidative decomposition, oxidase, arginine double hydrolysis, acetamidase, gluconic acid oxidation, nitrate reduction ammonia production test are positive.

Patients with Pseudomonas aeruginosa sepsis have copper-green proteinuria in the urine, and the patient's urine is adjusted to be acidic, alkaline and neutral. They are placed in the dark room and irradiated with ultraviolet light respectively. If there is abuminuria, light green fluorescence occurs.

X-ray findings of pneumococcal blood group scattered on both sides of bronchial pneumonia with nodular oozing shadows.

Diagnosis

Diagnosis and identification of Pseudomonas aeruginosa meningitis

Blood culture and cerebrospinal fluid routine, smear and culture should be done in time to identify pathogens and carry out corresponding antibiotic treatment and symptomatic treatment as soon as possible.

Clinical attention should be paid to the identification of meningitis caused by Gram-negative bacilli in the intestine.

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