Bacteremia is not typical. Fire in the blood: “dormant” bacteria can cause fatal diseases in healthy people

Bacteremia- presence of bacteria in the blood.

Reasons bacteremia

Penetration of the pathogen into the blood is observed in many infectious diseases and is a mandatory or possible component of their development.

Mild, temporary bacteremia can occur even when a person clenches his jaw, because bacteria living on the gums around the teeth enter the bloodstream. Bacteria often enter the bloodstream from the intestines, but they are quickly destroyed as the blood passes through the liver.

The number of microorganisms per unit volume of blood depends on the virulence of the pathogen and the resistance of the patient’s body. With prolonged and severe bacteremia, generalized and, in particular, septic forms of the infectious process usually form.

Symptoms bacteremia

Because the body can deal with small numbers of bacteria quickly, symptoms of temporary bacteremia rarely occur. However, as soon as sepsis develops, chills occur, body temperature rises, weakness, nausea, vomiting and diarrhea appear.

If treatment is not started, the infectious agents spread throughout the body and so-called metastatic foci of infection are formed.

The consequence of this may be meningitis - inflammation of the membranes of the brain, pericarditis - inflammation outer shell heart, endocarditis - inflammation inner shell heart, osteomyelitis - inflammation of bone tissue. With sepsis, abscesses (collections of pus) can form throughout the body.

Diagnostics bacteremia

A person who has a focus of infection in any organ suddenly experiences a sharp rise in body temperature. If sepsis develops, the number of white blood cells in the blood usually increases significantly. To identify the “culprit” microorganism, blood cultures are performed. However, it is difficult to isolate bacteria from a blood culture, especially if the person is taking antibiotics. For culture, sputum material from the lungs, urine, discharge from wounds and from places where catheters are inserted are also taken.

Treatment bacteremia

Bacteremia associated with surgery or catheter insertion urinary tract, usually does not require any treatment, especially if the catheter is quickly removed. However, before such procedures are performed, people at increased risk of developing inflammation in response to bacteremia, such as those with heart valve disease or a weakened immune system, are given prophylactic antibiotics.

A general clinical blood test is a test that reveals pathological conditions. An important component of therapy is identifying the cause of the disease.

Bacteria

Attention! Viral and bacterial etiology have similar symptoms. However, there are differences that are revealed using clinical analysis blood.

What is the difference between a viral and bacterial infection?

Bacteria are single-celled microorganisms without a formed nucleus. Capable of reproduction and metabolism. There are several forms of microorganisms:

• Cocchi.
• Bacilli.
• Spirilla.
• Vibrios.

Cocci have a round body shape and can be paired with other bacteria (diplococci) or exist separately (micrococci). Some form long chains (streptococci), while others form a quadratic structure (tetracocci). Bacilli are rod-shaped bacteria. They are different from each other and have a durable shell that allows them to survive the conditions environment(high/low temperature, oxygen or nutrient deficiency).

Bacteria do not have a formed nucleus, therefore they are classified as prokaryotes. Outside or inside human body An innumerable number of bacteria are present. A normal immune system ensures uninterrupted protection of the body from pathogenic environmental influences. Weakening of “protective” forces is a risk factor for the development of infectious diseases.

They do not live in the body for a long time. However, some types of viruses live in symbiosis with humans throughout their lives (Epstein-Barr virus). Such infections are not destroyed either by the immune system or by drug intervention (herpes, HIV and others).

Blood test for bacteria and viruses, interpretation of results

The viral or bacterial pathogen will be determined by the therapist based on the results of a general clinical blood test. When infected with microbes or viral particles, a number of biochemical changes occur in blood tests.

At viral infection The following changes occur in blood tests for viruses and bacteria:

• Lymphocytosis.
• Monocytosis.
• Neutrophilia.

To identify a specific type of virus (EBV, CMV and others) it is used enzyme immunoassay and PCR. As biological material blood is used. A blood test for viruses in a child is not sufficient to detect the disease, so urine, saliva and feces are taken with the blood for testing.

With this type of infection, the white blood cell level remains normal. Important for identifying etiology painful condition symptom complex. For a viral infection incubation period does not exceed 2 days, and for bacterial it lasts more than 5 days. Infection with viruses is manifested by a sharp rise in body temperature (up to febrile; above 38.8 degrees Celsius), chills, hyperhidrosis of the extremities and moderate myopathy.

Common symptoms indicating a viral disease:

• High temperature.
• Severe chills.
• Feeling faint.
• Weakness.
• Muscle pain.

Important! The presence of the above symptoms is a reason to consult your doctor. You should not engage in self-diagnosis or self-medication, as this leads to disastrous consequences.

Depending on what type of bacteria a person is infected with, changes in the indicators of a general clinical blood test depend. A bacterial infection has the following specific symptoms:

• Leukocytosis.
• Neutrophilia.
• Limocytopenia.
• Increased ESR levels.
• The appearance of metamyelocytes and myelocytes.

In addition to a general clinical blood examination, an enzyme immunoassay is prescribed. It allows you to identify papilloma, Helicobacter and others bacterial diseases affecting the functioning of the stomach or intestines. In some cases, a tank culture is prescribed for a bacterial infection, but the results will be ready only after 9 days. This is due to the fact that bacteria need time to grow in vitro.

Bacterial diseases (especially in gynecology) take a long time to develop and have a long incubation period. The symptom complex depends on the bacterium and the affected area. Respiratory bacterial infections include cough, rhinitis, headaches and low-grade fever body (not higher than 38 degrees Celsius). In rare cases, the body temperature rises to febrile.

How to get tested for viruses?

Analysis for viruses and infections in the human body is carried out together with clinical trial blood. Before submitting biological material, do not eat food for 12 hours. Men and women should limit their intake of psychotropic substances (nicotine, caffeine or alcohol). Tests for viruses and infections are taken on an empty stomach and in the morning.

Advice! Children and pregnancy should avoid psycho-emotional and physical stress before blood tests for viruses and bacteria.

Description:

Bacteremia is the presence of bacteria in the blood. Blood is normally sterile, and detection of bacteria in the blood (usually by blood culture) always indicates pathology.

Symptoms:

Bacteremia can cause several serious consequences. The immune response to bacteria can cause (blood poisoning) and, with a high probability of death. Bacteria can use blood to spread throughout the body (hematogenous spread), causing secondary foci of infection at a considerable distance from primary focus infection. An example could be .
Gram-negative bacteremia. The most common pathogens are E. coli, Klebsiella spp., Entembacter, Serratia, Proteus and P. aeruginosa. Sources of bacteria are the gastrointestinal tract, genitourinary system and skin. Predisposing factors - surgical interventions And medical manipulations(for example, catheterization) on the urinary tract and associated diseases.

Gram-positive bacteremia. The main causative agent is coagulase-positive S. aureus. Coagulase-negative staphylococci (S. epidermidis and S. saprophyticus) rarely cause lesions. Staphylococcal bacteremias are divided into primary (the pathogen enters from skin) and secondary (from the source existing infection). The most common sources are skin abscesses (even their slight palpation can cause dissemination of the pathogen). In hospital settings, almost all cases of bacteremia are caused by contamination of medical instruments. The main pathogens are coagulase-negative staphylococci.

Causes:

The presence of bacteria circulating in the blood is a serious complication of infections (such as and), operations (especially those involving work on mucous membranes such as the gastrointestinal tract), catheterization, or foreign bodies in an artery or vein (including intravenous infections, especially when taking drugs).

Treatment:

For treatment the following is prescribed:

Bacteremia associated with surgery or catheter insertion into the urinary tract traditionally requires no treatment, especially if the catheter is promptly removed. However, before such procedures are performed, people at increased risk of developing inflammation in response to bacteremia, such as patients with heart valve disease or a weakened immune system, are given prophylactic antibiotics.

Bacteria surround us all the time. There are a huge number of them on the surface of the skin; opportunistic bacteria are also present in the intestines. In addition, they can enter the genitourinary, respiratory and other systems of the body. However, most dangerous condition is the presence of bacteria in the bloodstream, or bacteremia (forumdisplay).

Main reasons

Bacteremia is pathological process, which can be caused by many different reasons, because there are a huge number of ways for bacteria to enter the body. Most often they enter the bloodstream through the following reasons:

• Violation of the rules of asepsis (preventing microorganisms from entering a sterile environment) and antiseptics (eliminating microorganisms where they may be) when surgical interventions.
• Long lasting serious illnesses that require long-term injection interventions or artificial ventilation lungs. Prolonged presence of foreign objects in the human body increases the chances of bacteria entering the bloodstream.
• Secondary bacteremia during infections is a condition characterized by the colonization of bloodstream bacteria against the background of an existing infection ( gastrointestinal tract, respiratory organs, genitourinary system).
• Risk factor for development this state are injection drug addicts, as well as people with immunodeficiency (HIV-infected).

Thus, bacteremia is typical for people with weakened immune systems and for those whose skin integrity is constantly compromised.

Pathophysiology

Bacteremia is a condition that may not cause any harm to the body for a certain period of time. However, if this process has been observed for a long time, bacteria can migrate to any internal organ, forming a focus of infection and inflammation there. As a result of this, abscesses (purulent foci limited by a capsule) and phlegmons (spilled purulent inflammation). Damage to the brain and heart is most dangerous.

In addition, when the valves and internal (endocardium) are damaged, a disease called infective endocarditis occurs. If not diagnosed and treated promptly, this disease causes destruction of the heart valves and leads to the development of heart failure.

Symptoms

As noted above, bacteremia is a process that can be asymptomatic for a long time, without causing any complaints in the patient. However, over time it makes itself felt.

The most typical symptoms are:

• disturbance of general well-being: severe fatigue, weakness;
• fever accompanied by sweating and chills;
• dizziness and headache;
• increased heart rate and breathing;
• Symptoms such as a drop in blood pressure and impaired consciousness may also indicate the development of septic shock.

Sepsis

Perhaps someone has the opinion that bacteremia and sepsis are two inseparable concepts, but this is not so. The first characterizes only the fact of the presence of bacteria in the body, while sepsis is more serious condition. And to make such a diagnosis, it is necessary to have the following signs:

• body temperature above 38 °C or below 36 °C;
• heartbeat more than 90 beats per minute;
• respiratory rate more than 20 cycles per minute;
• the number of leukocytes in the blood is more than 12 thousand/mm 3 or less than 4 thousand/mm 3;
• presence of bacteria in the bloodstream during blood culture.

Although, according to recent studies, the presence of bacteria in the blood is no longer a mandatory criterion for sepsis. That is, simply put, sepsis is an excessive reaction of the body to an infection.

Septic shock and multiple organ failure

Septic shock is considered as the next stage of sepsis, which is accompanied by a drop in systolic blood pressure below 90 mm Hg. Art. Moreover, this hypotension is unable to be corrected by infusion saline solutions. This means that the function cardiovascular system is so impaired that even increasing the volume of circulating blood using saline solutions cannot increase the pressure.

Multiple organ failure is a term that refers to dysfunction of almost all organs and systems of the body. It manifests itself as a decrease in the amount of urine excreted (oliguria), an even greater drop in blood pressure, respiratory depression, etc.

Thus, the concepts of bacteremia, septicemia and toxinemia are closely interrelated. The presence of bacteria and their breakdown in the blood causes the accumulation of toxins (toxemia), and these two conditions, in turn, lead to the development of septicemia.

Diagnostics

If the patient presents any of the complaints listed above, first of all the doctor issues a referral for general analysis blood. If this analysis confirms the presence bacterial infection in the body (increased number of leukocytes - leukocytosis, mainly due to an increase in neutrophils - neutrophilia), the next step will be a bacteriological examination using blood culture to determine bacteremia.

In addition, if the presence of bacteria is detected during culture, it is necessary to perform a chest x-ray, ultrasound examination chest and abdominal cavities, pelvic organs. These examination methods are necessary for the timely detection of purulent foci during internal organs.

Treatment

Even before blood culture results are obtained, antibiotics are prescribed to a patient with suspected bacteremia. wide range actions. This type of therapy is called empirical therapy. Based on the results of the culture (this may take several days), it is possible to change the antibiotic, depending on which drug the type of bacteria cultured is sensitive to.

As a rule, with the right antibiotic, your health improves on the second day of therapy. However, there is no need to interrupt antibiotic therapy ahead of schedule prescribed by the attending physician.

In addition to antibiotics, it is also necessary symptomatic therapy to alleviate the patient's condition:

• antipyretics for high temperature(“Paracetamol”, “Ibuprofen”);
• infusion of saline solutions at low blood pressure(isotonic sodium chloride solution, “Disol”, “Acesol”).

If there are purulent foci in the internal organs, surgical intervention is possible.

Bacteremia is a truly dangerous condition. When it is detected, it is necessary not only to eliminate the presence of bacteria in the bloodstream, but also to find out the root cause of their appearance and fight it.

Doctors have long established that the inflammatory processes that accompany many serious diseases are a reaction immune system body to infection, helping to destroy pathogens. But inflammation is also observed in diseases that are traditionally considered unrelated to microbial attacks: heart attacks, strokes, Alzheimer's disease and diabetes.

• Reuters

In parallel with inflammation in the body, blood clotting usually increases, the level of iron in it increases and so-called abnormal proteins appear, resulting from mutagenic errors in synthesis or due to external chemical exposure. Why with such various diseases Scientists do not yet know whether such similar symptoms are associated. But a discovery made by Douglas Kell of the University of Manchester and Recia Pretorius of the University of Pretoria, reported by The New Scientist, may shed light on the mystery.

Traditionally, it was believed that the blood of a healthy person is free of bacteria, since when sown in a nutrient medium in a Petri dish (a special vessel used in microbiology), no growth of microorganisms was observed. However, recent studies using DNA sequencing methods have shown that about a thousand bacteria “sleep” in every milliliter of our blood. In a dormant, “sleeping” state, they practically do not divide and do not pose a serious threat to the body (although they do not react to medicines). But an increase in the level of iron in the blood brings bacteria out of “hibernation”, and they begin their destructive work. Microorganisms begin to synthesize lipopolysaccharides (LPS) - large molecules located on their outer cell membrane. They awaken the immune system and, as a result, cause inflammation.

Unusual Suspect

Kell and Pretorius decided to find out whether there was a connection between LPS and the formation of blood clots. Since most bacteria enter the bloodstream from the intestines, the experiment used the common E. coli (Escherichia coli), which lives in the lower intestines of most warm-blooded animals, including humans. This bacterium has long been used as a model microorganism in laboratory research and well studied. Scientists mixed lipopolysaccharides secreted by E. coli with fibrinogen, a colorless protein contained in blood plasma that plays important role during the process of blood clotting. At inflammatory processes and the death of body tissue, the level of fibrinogen increases sharply. In the blood of a healthy person with enzymatic digestion During the coagulation process, fibrinogen polymerizes and precipitates into an insoluble fibrin-like precipitate. However, when exposed to E. coli LPS, fibrinogen has been shown to form abnormal fibrin clots, similar in shape and size to those seen in heart attacks, strokes, and deep vein thrombosis. Due to the abnormal structure of these clots, they are not broken down by blood enzymes, which leads to blood clots entering the bloodstream and can cause a stroke or heart attack. Moreover, to begin the process of formation of abnormal clots, only one molecule of LPS per several hundred million molecules of fibrinogen is enough.

According to the researchers, this proves that LPS works as a catalyst for the process, changing the structure of fibrinogen, and the reaction is of a chain nature, transmitted from protein to protein, similar to the deformation of prion proteins that cause the notorious Creutzfeldt-Jakob disease (spongy encephalopathy, in commonly known as “mad cow disease”). And since LPS is a trigger of inflammation, as a result of which the amount of fibrinogen in the blood increases, the process becomes an avalanche.

“There is no big discovery there. As for thousands of bacteria in one milliliter of blood, this is not entirely true. Finnish researchers have long ago established that many viruses and nanobacteria (less than 0.1-0.2 microns) live in our blood. In general, we coexist with bacteria and viruses; life on Earth began with them and will end with them. The fact that lipopolysaccharides are an important element of our immune system is also known fact, they knew this half a century ago. And it has long been known that bacteria play a big role in it. If a child does not fall or hurt his knees in childhood, then he does not develop immunity to many microorganisms. That’s why, by the way, people in villages get sick less often than in cities. So I don’t see any revelation in this work. Unfortunately, I have come across a lot of young researchers who pass off any of their experiments as some kind of discovery. Still, the history of science must be studied and known.”
Valery Fedorovich Galchenko, corresponding member of the Russian Academy of Sciences, head of the scientific direction "Microbiology" of the Federal Research Center of Biotechnology of the Russian Academy of Sciences

Inflammatory processes are usually accompanied by increased level free iron in the blood - this is observed, in particular, in diseases such as Alzheimer's disease and rheumatoid arthritis. Scientists believe that bacteria in the blood that have emerged from a dormant state may be associated with these diseases, forming amyloids. This is confirmed by data obtained by researchers at Harvard Medical School, published this spring. Scientists injected bacteria into the brains of mice and found that amyloid deposits formed in the rodents within 24 hours.

Strokes are considered main reason mortality in modern world, and the number of people suffering from Alzheimer's disease could grow to 100 million by 2050. The discovery of Kell and Pretorius may become important factor in search of ways to treat these and other diseases associated with the circulatory system. Likely ways, according to The New Scientist, could be, for example, removing dormant bacteria from the body or blocking the proteins they produce.

Vladislav Krylov