Blood and bone marrow bacterial culture
When local infections spread to the whole body and systemic infections occur, bacteria, bacteremia, toxemia or sepsis, can occur in the blood and bone marrow. Clinically, patients with fever, bloody signs and symptoms can be cultured in blood and bone marrow. Blood and bone marrow bacterial culture is used to detect microbial bacteria in the blood of patients with bacteremia and fungalemia. Most bacteremia is intermittent and needs to be confirmed by multiple cultures. Blood and bone marrow bacteria culture is commonly used in traditional broth enrichment method and automatic blood culture instrument detection method.Basic Information
Specialist classification: Infectious disease inspection and classification: pathogenic microorganism inspection
Applicable gender: whether men and women apply fasting: fastingAnalysis results:
Sterile growth in normal blood and bone marrow.
The pathogenic bacteria were detected as positive, suggesting that the pathogenic bacteria were infected.
Sterile growth in normal blood and bone marrow.Clinical significance
1. The blood and bone marrow of bacteria that may be infected in the blood should be free of bacteria. Once the bacteria are detected, they should be regarded as bacteremia, and the drug sensitivity test should be carried out. The common bacteria in the blood and bone marrow are mainly the following types.
(1) Gram-positive cocci, Staphylococcus aureus, especially in the past, especially Staphylococcus aureus (such as MRSA), followed by Staphylococcus epidermidis, Streptococcus hemolyticus, etc.; subacute endocarditis often Detection of α-hemolytic streptococcus (such as Streptococcus mutans, Streptococcus pneumoniae); suppurative pericarditis can be caused by Staphylococcus aureus, Streptococcus hemolyticus, Streptococcus pneumoniae and anaerobic bacteria.
(2) Gram-negative bacilli are common with Pseudomonas aeruginosa and other non-fermenting bacteria; typhoid, paratyphoid and other Enterobacteriaceae bacteria. Breathing culture can detect Bacteroides, Fusobacterium, and the like.
2. For the detection of less common bacteria, or the clinical performance is too different, can not be confirmed as an infection, in the following cases, should be considered positive.
(1) Check again, strictly aseptic operation, if there is still the same bacterial growth, it should be considered as positive.
(2) After 2 to 3 weeks of infection symptoms, when the corresponding antibody titer in the blood is significantly increased, it is of great significance, and the culture result should be regarded as positive.
(3) When necessary, blood samples from two different sites, or venous blood and arterial blood, should be considered positive when the same bacteria are detected.
(4) The same pathogen was detected in the blood culture and the culture of sputum, urine, pus, chest and ascites.
(5) Blood culture detects pathogenic bacteria, and clinical manifestations of bacteremia are based on the results of drug susceptibility test when sensitive antibiotics are used.
3. Possible causes and treatments when there are typical infections and repeated cultures are negative
(1) The timing is not properly controlled, and there is a high concentration of antibiotics in the blood at the time of the test. Avoid blood collection at high drug concentrations or use medium with antibiotic adsorption (neutralizing) agents.
(2) It may be L-type bacteria, anaerobic bacteria, virus infection, etc. Special culture methods or other inspection methods should be used.
(3) If the suspected systemic inflammatory response syndrome should not give up looking for infections and pathogens, it can be sent to the blood for several days.Positive results may be diseases: chronic osteomyelitis in children, other Salmonella infections in children, acute blood-borne osteomyelitis in children
Blood specimen collection should pay attention to:
First, the precautions before blood draw
1, do not eat too greasy, high-protein food the day before the blood, to avoid heavy drinking. The alcohol content in the blood directly affects the test results.
2. After 8 pm on the day before the physical examination, fasting should be done to avoid affecting the detection of indicators such as blood glucose in the second sky.
3, should relax when taking blood, to avoid the contraction of blood vessels caused by fear, increase the difficulty of blood collection.
Second, after blood draw should pay attention to:
1. After blood is drawn, local compression is required at the pinhole for 3-5 minutes to stop bleeding. Note: Do not rub, so as not to cause subcutaneous hematoma.
2, the pressing time should be sufficient. There is a difference in clotting time for each person, and some people need a little longer to clotting. Therefore, when the surface of the skin appears to be bleeding, the compression is stopped immediately, and the blood may be infiltrated into the skin due to incomplete hemostasis. Therefore, the compression time is longer to completely stop bleeding. If there is a tendency to bleed, the compression time should be extended.
3, after the blood draw symptoms of fainting such as: dizziness, vertigo, fatigue, etc. should immediately lie down, drink a small amount of syrup, and then undergo a physical examination after the symptoms are relieved.
4. If there is localized congestion, use a warm towel after 24 hours to promote absorption.
Third, the medical personnel to pay attention to blood collection:
1, should be collected in the early or peak period of the patient's fever, try to use antibacterial drugs before. Those who have already taken the drug should be collected before the next dose, and those who have the condition should use the medium containing the antibiotic adsorption (neutralizing) agent.
2, suspected subacute endocarditis and brucellosis patients, blood should be collected 3 to 4 times within 24 hours.
3, should be strictly aseptic operation to prevent sample contamination.
4. The amount of blood collected is usually 1/10 of the amount of the medium.
5. Anaerobic culture strictly avoids injecting gas into the culture bottle.
Bone marrow specimens are collected by bone marrow aspiration
First, patients should pay attention to:
1. If you have a history of hemophilia and disseminated intravascular coagulopathy, you should inform your doctor promptly.
2. Before the bone marrow puncture, do not be nervous because you are mentally prepared.
3. After the puncture is completed, do not eat spicy food and old soup.
Second, the physician should pay attention to when performing the puncture:
1. Preoperative and clotting time examination, patients with bleeding tendency should pay special attention when operating, and bone marrow puncture is forbidden for patients with hemophilia.
2. The syringe and puncture needle must be dry to avoid hemolysis.
3. After the puncture needle enters the bone, avoid excessive swing, so as not to break; the sternum puncture is not too strong, too deep (thinthral plate thickness is only 1.35mm, medullary cavity is 7.5mm) to prevent penetrating the medial plate injury and heart Big blood vessels.
4. The amount of aspirate fluid should not be excessive for cell morphology examination, so as not to affect the judgment of nucleated cell proliferation, cell count and classification results.
5. The bone marrow solution should be smeared immediately after it is taken out, otherwise it will solidify very quickly, causing the smear to fail.
6. If the bone is hard and does not penetrate into the medullary cavity during the puncture, the suggestion may be marble bone disease. It should be examined by bone X-ray. It is not allowed to be forced to prevent needle breakage.Inspection process
When the symptoms of infection appear 2 to 3 weeks, when the corresponding antibody titer in the blood is significantly increased, it is of great significance, and the culture result should be regarded as positive. Blood culture detects pathogens and has clinical manifestations of bacteremia. According to the results of drug susceptibility test, sensitive antibiotics are effective.Not suitable for the crowd
1, those who do not check the indications should not do this check.
2. Patients with hemophilia or bleeding tendency are contraindicated for this test.Adverse reactions and risks
1. Bloodletting may cause hematoma.
2, may be due to improper operation and infection or fever.