What is bacteriological culture, how and for what purpose is it carried out?
Main goal bacteriological research blood test is to determine the presence of bacteria in the blood. Since it is impossible to confirm or exclude bacteremia under a microscope due to an insufficient number of bacteria, the bacteria are first grown (reproduced) in a special nutrient medium containing all necessary elements for rapid bacterial growth.
When visible bacterial growth is detected, the bacteria-enriched culture is stained and examined under a microscope. This is how preliminary identification of the type of microorganisms present in the blood is carried out. For more accurate identification, inoculation of a liquid culture on a solid medium (in a Petri dish) is required. With such a study, you can see how colonies of bacteria grow. Chemical tests are performed on colony samples to accurately and definitively identify the type of microorganism.
After identifying the type of bacteria present in the blood, their sensitivity to antibiotics is determined. This is necessary in order to find out which medicine can be used to combat the identified type of bacteria most effectively.
Indications for testing bacteriological culture blood
Microbiologist Natalya Petrova: “An indication for a bacteriological analysis may be a suspicion of blood poisoning; long time elevated temperature bodies, for a reason that cannot be ascertained; suspected infectious diseases (for example, epidemic meningitis, staphylococcal and streptococcal infections, intestinal infections). Since a single blood test may be ineffective, a series of 2 or more studies can be performed over a certain period of time. To assert that the causative agent is a specific microorganism is made possible by the rapid (48 hours) detection of the microorganism, with repeated isolation of it from the blood or other types of test material (urine, sputum, etc.), in addition, the detection of this microorganism at the same time different types nutrient media."
When are samples taken for bacterial blood tests?
Blood culture should be obtained before antibiotic treatment is started because antibiotic use may delay or prevent bacterial growth, resulting in a false negative result. In patients with intermittent fever, blood should be drawn when the temperature rises or immediately after the peak temperature has passed. It is at this time that the blood contains maximum quantity bacteria. Many laboratories recommend giving a second blood sample no later than one hour after the first in order to increase the chances of detecting bacteria.
Required blood volume
In a patient with bacteremia, 1 ml of blood may contain only one microbial cell, so if you add insufficient blood to the bottle with the nutrient medium, you can get false negative result.
Paradoxically, a false negative result can also be obtained when too much blood is added to the nutrient medium. This happens because the blood in large quantities continues to be bactericidal. Of course, there is a trade-off between too little blood volume and too much blood volume. The optimal dilution of blood in a nutrient medium should correspond to a ratio of 1:10, the required volume (usually 5-10 ml), it all depends on what kind of nutrient medium is used for analysis.
Technique for performing bacteriological culture
When bacteriological culture, it is necessary to adhere to aseptic technique to exclude the possibility of bacterial contamination of the blood. If the sample is taken according to the rules, only those microorganisms that are in the patient’s blood will end up in the bottle with the nutrient medium.
Rules for collecting blood for bacteriological culture:
The results of bacteriological blood culture are divided into the following three groups:
No bacterial growth: Normal result, meaning the patient's blood is sterile.
Net bacterial growth: a result indicating that there is growth of one species of bacteria that was isolated from the culture. This result should be expected when the patient has sepsis.
Mixed growth: The result indicates that more than one species of bacteria was isolated from the culture. This type of blood infection is rare. Most often, mixed bacterial growth is a confirmation that the nutrient medium has been contaminated.
Flush the stomach of a patient with PTI
At the first signs of food poisoning (nausea, vomiting, abdominal pain, tenesmus, diarrhea), the patient needs to rinse the stomach by asking him to drink a liquid or by introducing it into the stomach through a tube. The procedure can be repeated at a later date if nausea and vomiting continue. For this purpose, use a 2% solution of sodium bicarbonate, a weak solution of potassium permanganate or ordinary boiled water. Rinsing is carried out until the rinsing waters become clean, without lumps of undigested food and mucus. Frequent vomiting and loose stool lead to dehydration of the body, so the patient, depending on the severity of his condition, is prescribed rehydration treatment for food toxic infection in children using rehydron, quartasol, trisol orally. Infusion rehydration therapy is indicated in more severe cases, with toxicosis with exicosis, and in this case, a 5% glucose solution, saline solutions, and Ringer-Locke solution are prescribed. Detoxification therapy includes the prescription of hemodez, polyglucin, reopolyglucin, which improve blood circulation and relieve symptoms of intoxication. Antipyretic and anticonvulsants and glucocorticoids are also prescribed. With strong pain syndrome antispasmodics are prescribed.
nutritional features of infectious patients
Basic rules therapeutic nutrition infectious patient
The founder of Russian dietetics, M.I. Pevzner, developed diet No. 13 for infectious patients, and recommended following the following rules when preparing a diet for an infectious patient:
A febrile patient should not be allowed to go hungry. He should receive enough food, but in small portions at a time.
Any overfeeding is contraindicated, even if the patient has an appetite.
If possible, you should exclude from your diet foods that mechanically irritate the digestive organs.
It is necessary to monitor the function of the excretory organs and, in case of constipation, include in the diet foods that have a laxative effect (sugar, honey, juices of raw vegetables, fruits and berries), and in case of diarrhea, exclude milk. pure form, cold drinks and limit the amount of sugar.
In case of kidney symptoms, it is necessary to exclude strong broths, extractives, and spices from the diet.
It is necessary to take into account the state of the patient’s nervous system, allowing the introduction into the diet of only a small amount of nutrients that irritate the nervous system (strong coffee, tea, very strong broth), or even excluding them completely.
During acute infections, the body's need for vitamins increases significantly. Of particular value are vitamins that in one way or another affect the state of the immune system. The richest foods in vitamin C are rose hips, black currants, citrus fruits, and sea buckthorn. Food sources vitamin A: liver, granular beluga caviar, egg yolk, butter, hard cheeses. Vitamin B2 (riboflavin) is found in large quantities in offal, yeast, almonds, cheeses, eggs, and cottage cheese. Vitamin B6 (pyridoxine) is found in offal, meat, beans, soybeans, rice, millet, and potatoes. D improves the state of anti-tuberculosis and antifungal immunity. Food sources of vitamin D: liver oil of fish and marine animals, salmon, herring, mackerel, caviar, tuna, egg, cream, sour cream.
Among the microelements, the most important for the state of the immune system is zinc, deficiency of which develops with enteritis, especially in patients who abuse alcohol. Food sources of zinc: shellfish, mushrooms, egg yolk, liver, meat. Legumes, sesame, and peanuts also contain a lot of zinc, but it is associated with phytic acid. Daily requirement in zinc – 15–25 mg.
Stages of diet therapy for infectious diseases
Against the background of a high fever, it is quite acceptable to only drink thirst-quenching drinks for 1–2 days; the patient should not be forced to eat. If fever continues for more than 5–7 days, then enteral or parenteral nutrition should be prescribed.
When the patient's condition improves after a drop in body temperature, an increase in appetite is often noted. However, there is no need to strive to completely satisfy it from the very beginning, since in the first 3-4 days temperature fluctuations are observed for some time, and the production of gastrointestinal enzymes is disrupted. That is why you should not sharply expand your diet during these 3-4 days.
With further expansion of the diet, the greatest attention should be paid to replenishing protein and vitamin deficiencies. Either diet No. 11 or diet No. 15 is used. The amount of protein in the diet should be 1.5 g/kg of ideal body weight, while the quota of fats and carbohydrates corresponds to the norms of a balanced diet. Convalescents are prescribed a diet with a restriction of foods that stimulate the central nervous system (strong coffee, tea, strong broths, spices, chocolate) and foods containing coarse fiber and essential oils (rutabaga, turnip, garlic, radish, radish). Cakes, pastries, products from shortcrust pastry. All types of culinary processing are allowed: boiling, stewing, baking and frying without breading. The diet is 3-4 times a day.
Sometimes convalescents may experience dyspepsia during a rapid expansion of their diet. In this case, it is necessary to appoint a fasting day (boiled vegetables without salt and oil, baked apples) and check whether the diet is composed correctly, whether the patient has taken into account the presence of concomitant chronic diseases of the digestive system, and, if necessary, make appropriate adjustments.
Blood collection for typhoid fever
Technique for collecting blood for culture. With strict adherence to sterility, draw 5-10 cm3 of blood from the cubital vein into a Record or Luer syringe, remove the needle with tweezers, burn the cannula of the syringe on an alcohol flame and then pour the blood into the flask with the medium; Burn the neck of the flask and the stopper before closing. Either broth or bile (50-100 cm3 of medium) is used as a nutrient medium. Technique for collecting blood for agglutination (Vidal reaction). From the flesh of the finger, pump 1.5-2 cm3 of blood into a sterile Pasteur pipette and, when full, seal it or draw 3-5 cm3 of blood from the cubital vein with a syringe, which is then poured into a sterile test tube. Store the collected blood in a cool place. If necessary, you can use filter paper; to do this, collect 2-3 falling drops of blood on a piece of paper measuring 5x10 cm, dry it in air and send it in a sealed envelope for research to the laboratory. Stool collection technique. Collection vessels (vessels, jars, etc.) should not be subjected to chemical treatment, but only to boiling. To better preserve the viability of microbes, it is recommended to mix feces with an equal volume of a preservative (30% glycerol solution in saline).
It is produced for typhoid-paratyphoid diseases, sepsis, meningococcal infection or other infections accompanied by fever, throughout the entire febrile period of the disease, but better in the initial period or at the height of the disease (with severe bacteremia). For the study, blood is taken from a vein in the elbow; in small children, blood is taken in smaller quantities from the earlobe, heel, and finger. Blood samples are taken after thorough skin preparation in compliance with aseptic rules, using a disposable sterile syringe. Inoculation of sterile material (blood or other fluids containing microbes in healthy individuals) on nutrient media is also best done at the patient’s bedside, or placed in a sterile container containing substances that prevent blood clotting, 0.3% sodium citrate solution, 0.1% solution sodium oxalate). Typically, 5-10 ml of blood is taken and inoculated into a vial containing 50-100 ml of medium. To do this, use a bottle with a nutrient medium (one for aerobes, the other for anaerobes). Blood culture is carried out on liquid nutrient media - 10% bile broth, 1% sugar broth, two-phase medium, as well as liquid and semi-liquid media for the cultivation of anaerobes at a dilution of 1:10. Vials with a nutrient medium are obtained in the laboratory; blood transfusion from a syringe into a vial must be done over the flame of an alcohol lamp, after removing the needle. The vial with the inoculation is sent to the laboratory, and in the evening and at night it is placed in a thermostat. It is important for the student to remember that the earlier from the onset of the disease the culture is performed. The greater the chance of getting a positive result. And, conversely, the later the blood is taken, the smaller the amount of pathogen in it and the less often positive results are obtained. And at normal temperatures - very rarely. You should know that to increase the number of positive blood culture results, it is recommended, in the absence of contraindications, to inject subcutaneously 1 ml of a 0.1% adrenaline solution 15-20 minutes before drawing blood, which promotes contraction of the spleen and the release of pathogens into the bloodstream (for example, with typhoid fever). paratyphoid diseases) The preliminary result of culture for typhoid-paratyphoid diseases is obtained after 2-3 days, and the final result - after 7-10 days. It should be remembered that increasing the frequency of blood cultures (three days in a row with a rise in temperature) significantly increases the frequency of isolation of microbes from the blood. In treated patients, blood for culture should be taken 5-6 times.
Lumbar puncture conducted by a doctor.
The nurse carries out: - preparing instruments; - preparing the patient; - assisting the doctor during manipulation; - provision proper care for the patient after the puncture.
The purpose of a lumbar puncture is therapeutic and diagnostic.
Equipment. Sterile cotton balls, tweezers, 3% alcohol solution of iodine (iodinol), 2.0 ml or 5.0 ml syringe, two needles, 0.5% novocaine solution, needle for spinal tap with mandrin, sterile test tubes, alcohol, sterile wipes, adhesive tape, sterile rubber gloves, referral forms to the clinical and bacteriological laboratory.
1. Place the patient in a sitting position, bending forward, or lying on his side with his knees brought to the stomach.
2. Disinfect your hands and wear sterile rubber gloves.
3. Treat the puncture site (the point between the fourth and fifth lumbar vertebrae) and the surrounding area with an alcohol solution of iodine (iodinol).
4. Anesthetize the skin with novocaine.
5. Conduct lumbar puncture: insert a needle with a mandrel into the point between the spinous processes of the fourth and fifth lumbar vertebrae.
6. Remove the mandrin (liquid should flow out of the needle in a stream or drop) and substitute a sterile test tube. Collect the required amount of liquid for examination.
7. Insert the mandrel into the needle and carefully remove the needle.
8. Treat the puncture site and apply a sterile bandage.
Note: - the patient is transported to the ward in a horizontal position, lying on his stomach, on a gurney; - for the first 2-3 hours the patient should lie on his stomach without a pillow; - Strict bed rest is required during the day.
Blood culture for sterility is a microbiological method of examining blood to detect infection in it and identify the causative agent of the disease. If necessary, the study is supplemented with an antibiogram that determines the sensitivity of the pathogen to antibacterial drugs. For a more accurate diagnosis, blood cultures for sterility can be performed 2 or 3 times.
Normally, human blood is sterile, but in some cases infectious diseases it is possible for bacteria and fungi to enter the bloodstream and develop bacteremia and fungemia. Most often they are caused by a severe and aggressive course of infection or decreased immunity (for example, with, etc.).
In what cases can a doctor prescribe a blood culture for sterility? How to properly prepare for this study? How is the analysis performed? What is the cost of the study? You will get answers to these questions by reading this article.
The following clinical cases may be indications for prescribing blood cultures for sterility:
Blood sampling for testing should be carried out before starting antibiotics or after maximum removal of these drugs from the body. The analysis should be performed on the days of maximum temperature rise.
The collection of material for research is carried out in a laboratory or manipulation room in compliance with the rules of asepsis. A disposable syringe and needle are used to collect blood. It is strictly forbidden to take blood from intravenous catheters (exceptions are cases when it is necessary to identify a catheter infection). Sometimes, before collecting material, to increase the reliability of the study, it is recommended to administer a subcutaneous solution of Adrenaline, after which pathogens are released into the blood.
The skin puncture site is treated with a 2% iodine solution, and after 1-2 minutes the iodine is removed with 70% alcohol. The lid of the sterile bottle with the nutrient medium is also treated with 70% alcohol. The skin must be dry before performing the puncture. In adults, blood is drawn from the ulnar vein, in children - from a finger.
After puncture of the vein, 10 ml of blood is drawn into a syringe for analysis. The needle is removed from the vein and the puncture site is re-treated with an antiseptic.
Before introducing the resulting blood into the vial, change the needle to a sterile one and pour the material with the culture medium into a container over a burning alcohol lamp. It is strictly prohibited to remove the lid from the container.
After collecting the material, the bottle is marked (the form must indicate the patient’s data, diagnosis and information about the antibiotics taken, if they are prescribed before blood collection, the date and time of sampling) and sent to the laboratory in a thermostat with a temperature of 37 ° C.
Colonies of microorganisms grown in a thermostat are sown on a Petri dish and discs moistened with an antibiotic are placed around its circumference. In the laboratory, blood to be cultured for sterility is placed in a thermostat and kept at a temperature of 37-38 °C for several days. After this time, colonies of bacteria appear on the surface of the nutrient medium, which can be identified under a microscope. Preliminary results can be obtained in 3 days, final results in 10 days.
After isolating the pathogen culture, its sensitivity to antibiotics is determined. To do this, microorganisms are transferred to another medium in a Petri dish, around the circumference of which discs moistened with antibacterial agents. The material is placed in a thermostat and after a few days the intensity of bacterial growth to a particular drug is monitored.
The results of the test must be interpreted by the attending physician. Normally, microorganisms are not detected in the blood. When a pathogen is present in the blood, a monoculture (one microorganism) or more than one type of bacteria is detected.
IN state laboratories A blood test for sterility is performed free of charge. The price of blood culture for sterility in private institutions depends on the laboratory in which the study is carried out. The cost of analysis can range from 700 to 3300 rubles.
If you have a prolonged fever of unknown origin, it is best to seek a referral for this test from an infectious disease specialist. The doctor will not only be able to interpret the results, but will also make a diagnosis and prescribe the most correct treatment. Also, blood culture for sterility is widely used in surgery, cardiac surgery, orthopedics, neurology and other areas of medicine.
A specialist talks about blood culture for sterility:
Blood test for sterility - a clinical study aimed at identifying pathogenic bacteria in the blood. Allows you to diagnose serious illnesses of various etiologies.
Attention! Correct diagnosis bacterial infections allows you to prescribe effective drug therapy. IN recent years There has been a significant increase in the number of bacterial infections resistant to modern antibiotics. Scientists believe this is due to widespread misprescription of antibacterial drugs.
Known antibacterial drugsWhat does a general clinical test for blood sterility show? A sterility test is carried out to detect bacterial infection in the blood. Normally, blood is sterile, but some microbes can disrupt this condition and lead to the development of diseases. In municipal and private clinics, a doctor who suspects bacterial infection writes out directions for bacterial culture.
Bacteremia in the blood indicates the presence of diseases:
The test identifies staphylococcal, streptococcal, rod-shaped and other bacterial pathogens. Bakposev – effective technique diagnostics that can identify the type of pathogenic microorganism. The main disadvantage of the method is long period research, which ranges from 4 to 15 days. Over such a period of time, an infectious pathogen can cause serious complications and lead to fatal outcome. Therefore, drug therapy begins at initial stages development of infection without waiting for test results from the laboratory. In the Russian Federation, drugs are prescribed first penicillin series, but in lately More and more data is emerging about allergic reactions for this antibacterial agent.
Clinical study blood Often, blood sampling for sterility is carried out in case of resistance to first-line antibiotics. Such patients have bacteria with reduced sensitivity to antibacterial drugs. Required condition blood culture for pathogenic pathogens - postoperative period, suspected sepsis and cardiac shunting. HIV-infected people are susceptible to the influence of harmful microorganisms. Such patients have Mycobacterium tuberculosis in their blood.
Biological material must be taken on an empty stomach and in the morning. Before the procedure, avoid taking fatty foods and excess quantity"fast" carbohydrates. Refuse to eat 12 hours before collecting biological material and conducting a hemotest. Women during pregnancy and infants avoid psycho-emotional and physical stress.
The use of psychotropic substances and medicines. Inform your doctor in advance about taking medications. Failure to comply with the conditions increases the likelihood that the hemotest will show a false positive result.
Blood is taken for sterility from a vein at the bend elbow joint. In a newborn child, material for research is taken from a finger. The technique of collecting blood for sterility is performed according to WHO standards.
Algorithm of actions on how to take blood for sterility:
Subsequently, the material is placed in an in vitro environment where bacteria multiply. Modern tools determine the type of harmful microorganism and interpret the research results.
Technique for collecting material from a vein Advice! When receiving an injection, there is a risk of infection or bleeding (especially if you have hemophilia or disseminated intravascular coagulation syndrome). Therefore, it is important to sterilize the skin surface before drawing blood.
Preliminary test results can be obtained in CMD in three days, and in Helix - in 5 days. The final result is in 8-15 days. Much depends on the type of pathogenic microorganism and the rate of its reproduction.
The video shows how a bacterial pathogen develops in the blood. Timely treatment and diagnosing such disorders is a sure step towards recovery. It is important to contact your doctor promptly if “alarming” symptoms occur.
Interpretation of clotting time according to Lee White, norms and methods of analysis Features of the PSA test and preparation for the test, what is it, why is this study necessary and what diseases does it detect?
A blood test for sterility is carried out in order to diagnose bacteremia in a patient, which may indicate that quite serious pathological processes are occurring in the body.
A tank is cultured for sterility to detect pathogenic bacteria and microorganisms in the blood, which include the following:
For example, to find out that a person has developed Staphylococcus epidermidis, multiple tests are performed.
Cultures are necessary for patients who have reduced immunity. For example, tuberculosis microbacteria may be detected in patients with HIV infection.
This type of analysis is prescribed to patients before prescribing therapy in order to avoid obtaining incorrect results.
In infectious diseases, bacteria or microorganisms can penetrate the bloodstream and enter other systems of the body located at a distance from the source of infection. If bacteria are present in the blood, this indicates that the pathogenic process has gone far. This is accompanied by various disorders in the functioning of the heart, an increase in the number of white blood cells and an increase in temperature.
Blood cultures for sterility make it possible to diagnose diseases such as:
To detect bacteria and establish their type, produce thorough research pathogen. If the study reveals that microorganisms have entered the human body, then you need to find out what risk they pose for infecting various body systems. Defining the disease is the main objective of this study.
Then, using the data from the studies, the doctor prescribes to the patient necessary tests and therapy.
Cultures for sterility are prescribed when it is impossible to determine the exact cause of certain symptoms. Cultures are done if the patient has it for unknown reasons. for a long time doesn't work high temperature. It is performed on patients with suspected meningitis or sepsis.
In this case, bacteria present in the blood are determined. They can be dangerous or opportunistic. Tank culture determines not only the presence of microorganisms, but also the stage of the disease. The study also determines the sensitivity of bacteria to antibiotics.
Do not drink alcohol or drink before the test fatty foods. U healthy people blood is sterile. This study determines the presence of microbes in the blood that appear during infectious diseases or various manipulations. The study is carried out for people with prolonged fever and reduced immunity.
The analysis is performed in the laboratory by drawing blood from a vein in the elbow joint. Blood is taken from the child's finger. It is necessary to pre-treat the skin disinfectant. When drawing blood, use a disposable syringe.
Take 5-10 ml of blood and place it in a bottle containing 50-100 ml of nutrient medium. The analysis is poured into a bottle over a burning alcohol lamp. If it is not possible to deliver the patient to the laboratory, then the analysis is placed in a thermostat and transported to the test site.
The sooner the seeding is done, the more likely it is to get a positive result.
In order to increase the likelihood positive result analysis, sometimes the doctor prescribes a subcutaneous injection of 1 ml of adrenaline solution 20 minutes before the analysis. This causes the spleen to contract and bacteria to enter the bloodstream.
When carrying out tank seeding, the preliminary result is obtained after 3 days, and the final result can be obtained after 10 days.
The main purpose of a sterility test is to determine the presence of pathological bacteria in the body. After receiving the analysis, the specialist will be able to select necessary medications and appoint effective treatment diseases.
