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Bacteriuria is the presence of bacteria in the urine. Normally, urine is sterile. Bacteriuria is a symptom of inflammatory diseases of the kidneys and urinary tract. However, not every detection of microorganisms in centrifuged urine sediment is clinically significant.

A generally accepted indicator reflecting the true nature of bacteriuria is the titer of microbial bodies, amounting to 10 4 -10 5 CFU in 1 ml of urine. Titer reaching 10 4 CFU/ml. interpreted as bacterial contamination of urine.

It must be kept in mind that these parameters are conditional. Each clinical situation requires their correction. With a decrease in cellular and humoral immunity due to various factors(including immunosuppressive therapy), in conditions of hemodilution of polyuria, the activity of the inflammatory process in the kidneys and urinary tract may be indicated by a lower level of titer of microbial bodies - up to 10 4 CFU/ml.

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Causes of bacteriuria

If a person's kidneys are healthy and their tissue is not damaged, bacteria will not be able to penetrate from the bloodstream into the urine. Bacteriuria is observed with inflammation in the kidneys, when the renal parenchyma is affected by bacteria, with infection of the bladder, inflammation in the prostate gland, and it is also provoked by catheterization of the ureters and bladder, insertion of bougies into the urethra, and cystoscopy.

The degree of bacteriuria may vary and become severe with the following pathological conditions:

1. Obturation (closure) of the ureter with a calculus, when a pathological contraction disorder is formed and urine returns to the kidney, already infected with bacteria. There are also other possible causes of impaired outflow from the upper zone of the urinary tract.
2. Prostate adenoma, which becomes a source of inflammation and accordingly provokes bacteriuria. Significant narrowing of the urethra (stricture) and urinary retention can also increase the degree of bacteriuria.

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Bacteriuria can have both descending and ascending causes.

The descending method of infection entering urine is the penetration of bacteria into the urine from the inflamed vesica urinaria - bladder, from infected kidney tissue, from the prostate gland, which has hyperplastic glandular tissue. The ascending route of urine infection is the penetration of microorganisms into urine as a result of unsuccessful catheterization, urological endoscopy - cystoscopy, bougienage, as well as from the large intestine or vulva, if the rules of personal hygiene are not followed (lymphohematogenous route).

Bacteriuria occurs when it penetrates into the urine various types bacteria – these can be streptococci, Escherichia coli and Pseudomonas aeruginosa, staphylococci or bacteria of the genus proteus. Any type of bacteria entering the genitourinary area causes inflammation of the urinary system or kidneys, but infection by microorganisms is also possible in certain areas of the colon, causing proctitis. Bacteriuria is observed in those people who suffer from chronic constipation, hemorrhoids, much less often in patients with brucellosis, typhoid fever, paratyphoid fever and leptospirosis due to the low prevalence of these diseases.

Pathogenesis

What is bacteriuria?

Bacteriuria is the presence of microorganisms (bacteria) in the urine, which are detected by microscopic examination of urine, usually due to inflammatory diseases of the urinary tract, kidneys and genital organs in men.

Urine in healthy people, in principle, should not contain bacteria; in the bacterial sense, the sterility of urine is an indicator of the health of the kidneys and urinary tract. However, when they become infected, microorganisms enter the urine, bacteriuria develops, and leukocyturia and pyuria are possible. Not every urine contamination can be considered bacteriuria; there are clear boundaries in microscopic identification - an excess of 105 per 1 milliliter of urine is a sign of an inflammatory bacteriological process. The longer bacteria-infected urine remains in the bladder, the more pronounced the degree of bacteriuria.

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Symptoms of bacteriuria

Bacteriuria demonstrates symptoms in accordance with the underlying disease. Bacteriuria occurs (diagnosed) most often with pyelonephritis, urethritis and cystitis.

Bacteriuria can also be a symptom of the following pathologies:

• Prostate adenoma.
• Prostatitis, both chronic and in the acute stage.
• Diabetes.
• Bacterial sepsis.
• Urethritis.

Bacteriuria exhibits symptoms characteristic of pyelonephritis, urethritis and cystitis; other diseases do not have specific symptoms, which make it possible to differentiate the nosology only by laboratory analysis of urine.

Bacteriuria, symptoms similar to those of pyelonephritis:

• Dysuria – frequent or slow urination, burning, pain.
• Spontaneous release of urine.
• Transient nausea, sudden urge to vomit.
• Sharply rising body temperature, chills.
• Low-grade fever for 1-2 weeks.
• Pain in the lumbar region.
• Pain in the lower abdomen, in the bladder area.
• Cloudy urine, often interspersed with pus, with an unpleasant odor uncharacteristic of urine.

Bacteriuria, symptoms similar to those of urethritis:

• Discharge from the urethra, often with pus.
• Painful urination, dysuria.
• Hyperemic edges of the urethra, irritation, burning.
• Pain in the perineum.
• Increased body temperature, chills.
• General deterioration of condition, weakness.

Bacteriuria, symptoms identical to those of cystitis:

• Dysuria is frequent, painful urination.
• Burning during urination.
• Frequent urge to urinate with little urine output.
• Uncharacteristic odor of urine.
• Cloudy urine, change in color.
• Chronic aching pain in the lower abdomen.
• Possible increase in body temperature.
• Discharge from the urethra, often with pus.

Where does it hurt?

Forms

True bacteriuria and false bacteriuria

True bacteriuria is bacteria that not only enter the urinary tract, but also multiply there, causing severe inflammation. False bacteriuria - bacteria penetrate the bladder and urinary tract, but do not have time to spread and multiply due to the fact that the person either has an active immune system or is taking antibacterial therapy for an inflammatory disease.

If bacteria accept urine as a nutrient medium, where there are slightly alkaline and neutral conditions necessary for them, they begin to multiply, sometimes their number exceeds 100,000 in one milliliter of urine. True bacteriuria or significant bacteriuria, as it was called back in the middle of the last century by microbiologists Kass and his colleague Finland, is indisputable evidence for the diagnosis of urinary tract infection. Despite the fact that signs of inflammation in the bladder may appear earlier at much lower levels, the Kass and Finland parameter is the only statistically confirmed one and is used in laboratory practice in our time as the main criterion.

Latent bacteriuria, asymptomatic bacteriuria

Latent bacteriuria is most often determined during a routine medical examination in people who are not bothered by either the bladder, kidneys, or impaired urination. Asymptomatic bacteriuria is especially often detected in pregnant women.

In addition to the fact that a chronic asymptomatic inflammatory process poses a threat to human health, latent bacteriuria carries the threat of infection and transmission of bacteria to others, provided that the pathogen is a member of the Enterobacteriaceae family - that is, the causative agent of typhus. The fact that the patient has asymptomatic bacteriuria can be said after a positive two-stage urine test. The collection of material should occur at intervals of 24 hours, and the bacterial indicator should be twice confirmed within 100,000 per milliliter of urine.

Most often, asymptomatic bacteriuria is detected in women and girls. In men, during a screening examination, asymptomatic bacteriuria is detected - this is the reason for further diagnostic searches for latent prostatitis. Also quite often, latent bacteriuria is detected in patients over 65 years of age, when bacterial colonization is detected as chronic, lasting for many years. Most often, asymptomatic bacteriuria occurs in men with prostate hyperplasia and disruption of the outflow of urine in which bacteria multiply. In most cases, in elderly people, this indicator is not threatening, since the isolated microorganisms are not determined to be pathogenic during the study.

Diagnosis of bacteriuria

Bacteriuria in urine is determined by collecting fresh urine; as a rule, the middle portion is collected. A urine test for bacteriuria is carried out after following all hygiene procedures in order to avoid distortion of the results obtained, this is especially important for female patients. The speed of research is also important, that is, from the moment the material is collected until it reaches the laboratory directly, this is necessary to reduce the risk of flora reproduction in warm conditions with access to air. Of course, the most “pure” in this sense are tests collected by catheterization or aspiration, but these methods can also provoke bacteriuria, so they are used only in exceptional cases, according to strict indications, for example, when the patient is immobile or atony of the bladder.

A urine test for bacteriuria can be performed in several ways.

Bacteriuria in urine is detected either during routine clinical examinations, or during an already developed inflammatory process. Depending on the purpose and urgency of diagnosis, either highly sensitive methods, such as urine culture for bacteriuria, which require a lot of time to process the results, or fast, but not entirely accurate methods by which bacteriuria is determined in urine, can be used.

Approximate chemical methods are used as an express method:

• TTX test or method for the reduction of triphenyltetrazolium chloride, which uses the property of bacteria to convert the color of colorless tetrazolium salts to blue (formazan derivative).
• The Griess test is a nitrite method, when nitrates, when interacting with present bacteria, are transformed into nitrites. Nitrites, in turn, are detected using special Griess reagents. The test is suitable for material (urine) of adults, since urine in children usually does not contain nitrates.
• Glucose reduction test, when the ability of microorganisms to reduce glucose in small quantities is used. A reagent (paper strip) is dipped into the morning urine sample, which indicates the presence or absence of glucose. If there is no certain amount of glucose, this means that bacteria have “absorbed” it. The test is not 100% informative, but as an express method it is considered acceptable at the initial diagnostic stage.

Urine culture for bacteriuria

The most informative is urine culture for bacteriuria, when the number of reproducing bacteria within certain normal limits is calculated. This method is considered the most sensitive, especially for determining the degree of bacterial colonization, but requires 24 to 48 hours to complete. The Gould method is less time consuming and more simplified. Sowing urine for bacteriuria according to Gould is a method when the material is sown on agar, in a special Petri dish, in 4 sectors. Each time, urine is transferred to the next sector using a sterile platinum loop. To determine the degree of bacteriuria, you only need 24 hours; this time is enough to incubate bacteria at a comfortable temperature for them - 37 degrees. Next, the number of bacteria is calculated using a special table. Also among faster sowings is a method in which plates coated with a nutrient medium are immersed in urine. After immersion in urine, the plates are quickly transferred to special containers, where the bacteria are incubated at a warm temperature for 12-16 hours. The degree of bacteriuria is determined by comparing the results with the normal scale. This is the most accurate test, the reliability of which is within 95%.

It is advisable to carry out any analysis for bacteriuria twice, since even with false bacteriuria, the second culture can show a significant increase in the number of bacteria. This is explained by the fact that the first study may have been carried out with material that was collected during heavy drinking or dysuria; distortion is also possible when taking antibiotics or antiseptic drugs. In addition, bacteriuria in urine, with a properly selected research method, makes it possible to identify the true pathogen, determine its sensitivity to medications and select adequate treatment.

What needs to be examined?

How to examine?

What tests are needed?

Who to contact?

Treatment of bacteriuria

Any type of bacteria in urine is a signal of possible inflammation in the genitourinary area; therapeutic measures and the choice of drugs depend on the degree of bacteriuria, the age of the patient and his physiological state.

Acute infectious inflammation is treated with antibiotics latest generation with a wide spectrum of action and minimal side effects. To treat chronic infections, repeat culture for bacteriuria and an antibiogram are needed to determine the sensitivity of the pathogen to a specific group of drugs.

Treatment of bacteriuria in pregnant women

Bacteriuria during pregnancy is a fairly common phenomenon, not always associated with inflammation. Often, bacteria in the urine appear due to elementary stagnation of urine; also, the growing uterus can put pressure on the kidneys and bladder, causing weakness of renal activity and physiological changes in the structure of urine; in addition, the composition of urine is also affected by the hormonal system, which is unstable for all nine months condition. Therefore, bacteriuria in pregnant women requires repeated research and confirmation or refutation of the primary results. If the number of microorganisms really exceeds the norm, treatment of bacteriuria in pregnant women is carried out in the most gentle, but at the same time effective way.

The first thing to do is to activate urinary excretion (passage) and reduce the pH of urine using diuretic aseptic drinks, for example, cranberry juice. Next, as a rule, drugs of the cephalosporin group, less often penicillins, are prescribed in tablet form for a course not exceeding 3-5 days. It is this period that is considered in clinical practice to be sufficient for a single attack on bacteria and gentle on the body of the mother and fetus. The first months of pregnancy allow the use of semi-synthetic drugs - amoxicillin, ampicillin; the second trimester allows the use of macrolides. The effectiveness of antibiotic treatment is monitored by repeated cultures for bacteriuria. It is necessary to avoid prescribing the entire group of tetracyclines, fluoroquinolols, and antifungal drugs. As maintenance therapy, the prescription of drugs from the nitrofuran group is indicated; they are usually taken at night.

Asymptomatic bacteriuria during pregnancy is treated with more gentle, rather preventive methods, including herbal medicine, homeopathic remedies, such as Canephron, Cyston. Bacteriuria during pregnancy also involves the use of very powerful active drugs that are taken once. These drugs include Monural - an effective uroantispetic, which is prescribed 2-3 times a day, 3 grams per day. If a massive single dose of the drug does not produce results, treatment with cephalosporins is necessary for one week, and possibly for a longer time. It is also important to monitor the timely emptying of the bladder throughout the entire treatment period and prevent urine stagnation; for this, the pregnant woman’s menu should include cranberry and rosehip juice and diuretic infusions.

Asymptomatic bacteriuria during pregnancy is dangerous not in itself, but because it can provoke infection of the urinary canal and create conditions for the development of pyelonephritis. In addition, asymptomatic bacteriuria is a risk factor for the birth of a child with underweight, premature rupture of water, anemia, preeclampsia, and placental insufficiency. That is why treatment of bacteriuria in pregnant women should be as effective as possible in order to promptly prevent possible complications.

In general, treatment of bacteriuria in pregnant women should adhere to the following principles:

• Only those drugs are prescribed that are guaranteed to be safe and meet the bioavailability criteria.
• When choosing drugs, it is necessary to take into account the trimester of pregnancy, especially up to 5 months.
• The entire treatment process must be carried out under regular and strict medical supervision, including blood and urine screening tests.

Treatment of bacteriuria in children

Bacteriuria in children, especially in asymptomatic form, does not require independent separate therapy. It is enough to eliminate the main source of infection, and this is actually achieved by antibacterial therapy and activation of the immune system. In addition, treatment of bacteriuria in children is often associated with compliance with basic hygiene rules, which should be followed by the parents of the sick child. Also, bacteria in urine often have the opportunity to multiply due to infrequent urination: the child “forgets” to urinate while playing too much. These points seem not so important, but according to statistics, about 25-30% of cases of detection of microorganisms in the urine of children are associated with precisely such reasons, which practically do not require treatment. Establish a diet, monitor timely urination, eliminate constipation and regularly take baths and showers - sometimes this is quite enough for asymptomatic bacteriuria to go away without a trace. If bacteriuria in children is a consequence of cystitis or pyelonephritis, treatment should be adequate to the underlying disease.

Therapeutic elimination actions bacterial infection for cystitis, they are aimed at improving urination and neutralizing the infectious pathogen. Among medications, preference is given to urospetics and antispasmodics; antibacterial drugs are prescribed only when a high degree of bacteriuria is confirmed. As drugs that are relatively safe in terms of availability side effects, inhibitor-protected penicillins are chosen - amoxicillin; third-generation cephalosporins are chosen as an alternative. Antimycotic agents and macrolides are prescribed only in situations where atypical flora is detected in the urine. Like any other antibacterial therapy, taking antibiotics lasts at least 7 days. Among herbal remedies, it is good to take decoctions of lingonberry, calendula or plantain leaves. In addition, diet therapy, which is an integral part of the treatment of bacteriuria in children, should be long-term and should be followed for at least three months after completion of treatment.

Urine analysis for the degree of bacteriuria needed to determine the presence of pathogenic bacteria in the urinary tract. Normally, in humans, urine in the urinary tract is sterile, but microorganisms can enter the urine from the perineum and lower third of the urethra without causing inflammation. A urine test to determine the degree of bacteriuria is prescribed to all patients with inflammatory diseases of the urinary tract. All microorganisms, according to their ability to cause infectious diseases, are divided into:

• Pathogenic (should not be normal, capable of causing disease)
• Non-pathogenic (normally present in the body and do not cause disease)
• Opportunistic (normally released in small quantities, they begin to actively reproduce under certain conditions)

By analyzing urine for the degree of bacteriuria, the doctor identifies the presence of infectious inflammation and prescribes the necessary treatment.

This analysis allows you to identify the level of bacteriuria, determine the cause of inflammatory diseases of the urinary tract, and also monitor the cure after treatment.

Method

The sector sowing method is used. With this method, the test material (urine) is placed on a nutrient medium, then the number of microbial cells in 1 ml is determined. the material being studied.

Reference values ​​- normal
(Degree of bacteriuria, urine)

Information regarding the reference values ​​of indicators, as well as the composition of the indicators included in the analysis, may differ slightly depending on the laboratory!

Urine test for bacterial culture ( bacteriological examination) is used to detect bacteria in urine, select antibacterial drugs and monitor the treatment of infectious and inflammatory diseases of the pelvic organs.

Bacteria in urine

Infectious and inflammatory processes in the urinary tract are characterized by a recurrent course with a high probability of developing complications. The urethra and bladder are most often affected, and the infection often spreads to the ureters and kidneys. The disappearance of clinical signs of an acute bacterial infection in the urinary tract often does not indicate recovery, but the chronicity of the process, i.e. its transition to a sluggish chronic form. Inflammation and bacteriuria (presence of bacteria in the urine) remain, which helps to identify urine bacteria.

Normally, there are no microorganisms in the urinary tract, with the exception of the distal urethra, which is populated by microflora with skin perineum (in women also from the vulva).

95% of all pelvic inflammatory diseases are caused by microorganisms. The causative agents of urinary tract infections are usually Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Citrobacter, Proteus mirabilis, Serratia. In addition, staphylococci (S. epidermidis, S. aureus, S. saprophyticus), streptococci (S. pyogenes), mycoplasma (Mycoplasma), etc. become infectious agents. In uncompensated diabetes mellitus, microscopic fungi of the genus Candida are often found in the urinary tract.

Urinary tract infections are promoted by pathologies in which the outflow of urine is disrupted, as well as systemic diseases. In children, persons old age and weakened patients, the infectious process often occurs in a latent form or has nonspecific manifestations (digestion, weight loss, etc.).

To collect urine for bacterial culture, you should not use glass jars, household plastic containers, or use non-sterile disposable containers.

To determine the causative agent, bacterial culture of urine is performed. A referral for testing is usually issued by a therapist, urologist, or obstetrician-gynecologist. If necessary, the doctor will explain in detail what a urine culture test is, which shows this study, how to collect material, how long the test takes. Only a specialist should decipher the result obtained.

Indications for analysis

Unlike clinical analysis urine, bacteriological analysis is not carried out for preventive purposes, but is prescribed if there are signs of a urinary tract infection. The reason for prescribing a bacterial urine culture may be the detection of bacteria or fungi during a general urine test. In addition, this study is usually prescribed to patients with recurrent cystitis, paranephritis, pyelonephritis, chronic urethritis, diabetes mellitus, as well as when monitoring the condition of HIV-infected patients, etc. Urine analysis for bacterial culture is a mandatory test that is carried out for pregnant women; in 3–10% of cases, asymptomatic bacteriuria is determined.

Urine for bacteriological analysis is taken before the start or 7–14 days after completion of antibacterial therapy (control study), unless other conditions are specified by the attending physician.

Preparing for a urine test for bacterial culture

There are a number of rules for preparing for donating urine for bacteriological examination, compliance with which allows you to obtain the most reliable result.

In acute infectious and inflammatory processes, a monoculture is usually isolated against the background of high-grade bacteriuria, and in chronic ones, associations of microorganisms are usually isolated against the background of low-grade bacteriuria.

Women should not donate urine for bacterial culture during menstruation and for two more days after its end, since menstrual discharge, which is highly likely to get into the collected material, will affect the result of the study. It is also not recommended to use contraceptives two days before the test. medications in the form of vaginal suppositories. Douching should not be done before taking material for analysis.

Rules for collecting material for analysis

Before collecting urine, thoroughly clean the external genitalia without using antibacterial soap. To prevent urine contamination, men are advised to thoroughly rinse the penis and the fold of the foreskin before collecting material. For the study, it is necessary to collect the average portion of the first morning urine (that is, the initial and last portions are flushed down the toilet). Urine is collected in a special sterile disposable container, which is given to the laboratory before the analysis or purchased at the pharmacy. Some laboratories can purchase a transport tube containing a preservative (usually boric acid). When collecting urine, you should not touch inner wall container.

Material for bacteriological examination in infants is collected using a urine bag, which can be purchased at a pharmacy, and then poured into a sterile container.

To collect urine for culture, you should not use glass jars or household plastic containers, since it is usually not possible to ensure the sterility of such containers at home. In addition, non-sterile disposable containers should not be used.

The material must be delivered to the laboratory no later than two hours after collection.

Normally, there are no microorganisms in the urinary tract, the only exception being the distal urethra, which is populated by microflora from the skin of the perineum.

Analysis result

The main task of the analysis is to identify microorganisms in urine and determine their etiological role. The type of infectious agent, the degree of bacteriuria, the detection of microorganisms in repeated studies, etc. are taken into account.

Bacterial culture of urine is carried out on nutrient media using a bacteriological loop, swab or spatula. Normally, there is no growth of microorganisms; signs of microbial growth indicate the presence of a bacterial infection in the urine, i.e. bacteriuria.

The degree of bacteriuria allows for differential diagnosis of the infectious process from contamination of urine with normal microflora. Thus, bacteriuria up to 10 3 microbial cells in 1 ml of urine usually indicates the absence of an infectious-inflammatory process and, as a rule, is determined in the case of urine contamination; with bacteriuria 10 4, the result is questionable and there is a need for a repeat study; 10 5 or more - infectious and inflammatory process.

In order to control the therapy, the change in the degree of bacteriuria is assessed; its decrease indicates the effectiveness of the therapy used. medicines. However, when deciphering a urine test for bacterial culture, it should be taken into account that in some cases (during antibacterial therapy, low pH values ​​and/or specific gravity of urine, impaired passage of urine, etc.), a low degree of bacteriuria can be determined in the presence of a pathological process. For this reason, the identification of infectious agents found in urine is also important (repeated isolation of bacteria of the same species usually indicates the presence of infection).

Unlike clinical urine analysis, bacteriological analysis is not carried out for preventive purposes, but is prescribed if there are signs of a urinary tract infection.

The detection of a monoculture or association of microorganisms in the urine is of diagnostic importance. In acute infectious and inflammatory processes, a monoculture is usually isolated against the background of high-grade bacteriuria, and in chronic ones, associations of microorganisms are usually isolated against the background of low-grade bacteriuria.

In addition to identifying the infectious agent, a urine culture test can determine the antibiotic sensitivity of isolated strains of microorganisms.

To make a diagnosis, data from not only urine culture, but also other studies are usually used, and clinical signs of pathology are also taken into account.

Video from YouTube on the topic of the article:

A urine culture test (bacteriological examination) is used to detect bacteria in urine, select antibacterial drugs and monitor the treatment of infectious and inflammatory diseases of the pelvic organs.

To make a diagnosis, data from not only urine culture, but also other studies are usually used, and clinical signs of pathology are also taken into account.

Bacteria in urine

Infectious and inflammatory processes in the urinary tract are characterized by a recurrent course with a high probability of developing complications. The urethra and bladder are most often affected, and the infection often spreads to the ureters and kidneys. The disappearance of clinical signs of an acute bacterial infection in the urinary tract often does not indicate recovery, but the chronicity of the process, i.e. its transition to a sluggish chronic form. Inflammation and bacteriuria (presence of bacteria in the urine) remain, which helps to identify urine bacteria.

Normally, there are no microorganisms in the urinary tract, with the exception of the distal urethra, which is populated by microflora from the skin of the perineum (in women, also from the vulva).

95% of all pelvic inflammatory diseases are caused by microorganisms. The causative agents of urinary tract infections are usually Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Citrobacter, Proteus mirabilis, Serratia. In addition, staphylococci (S. epidermidis, S. aureus, S. saprophyticus), streptococci (S. pyogenes), mycoplasma (Mycoplasma), etc. become infectious agents. In uncompensated diabetes mellitus, microscopic fungi of the genus Candida are often found in the urinary tract.

Urinary tract infections are promoted by pathologies in which the outflow of urine is disrupted, as well as systemic diseases. In children, the elderly and weakened patients, the infectious process often occurs in a latent form or has nonspecific manifestations (digestion, weight loss, etc.).

To collect urine for bacterial culture, you should not use glass jars, household plastic containers, or use non-sterile disposable containers.

To determine the causative agent, bacterial culture of urine is performed. A referral for testing is usually issued by a therapist, urologist, or obstetrician-gynecologist. If necessary, the doctor will explain in detail what a urine test for bacterial culture is, what this study shows, how to collect the material, and how long the test takes. Only a specialist should decipher the result obtained.

Indications for analysis

Unlike clinical urine analysis, bacteriological analysis is not carried out for preventive purposes, but is prescribed if there are signs of a urinary tract infection. The reason for prescribing a bacterial urine culture may be the detection of bacteria or fungi during a general urine test. In addition, this study is usually prescribed to patients with relapses of cystitis, paranephritis, pyelonephritis, chronic urethritis, diabetes mellitus, as well as when monitoring the condition of HIV-infected patients, etc. Urine analysis for bacterial culture is one of the mandatory studies that are carried out for pregnant women, in 3– Asymptomatic bacteriuria is determined in 10% of cases.

Urine for bacteriological analysis is taken before the start or 7–14 days after completion of antibacterial therapy (control study), unless other conditions are specified by the attending physician.

Preparing for a urine test for bacterial culture

There are a number of rules for preparing for donating urine for bacteriological examination, compliance with which allows you to obtain the most reliable result.

In acute infectious and inflammatory processes, a monoculture is usually isolated against the background of high-grade bacteriuria, and in chronic ones, associations of microorganisms are usually isolated against the background of low-grade bacteriuria.

Women should not donate urine for bacterial culture during menstruation and for two more days after its end, since menstrual discharge, which is highly likely to get into the collected material, will affect the result of the study. It is also not recommended to use contraceptives or medications in the form of vaginal suppositories two days before the test. Douching should not be done before taking material for analysis.

Rules for collecting material for analysis

Before collecting urine, thoroughly clean the external genitalia without using antibacterial soap. To prevent urine contamination, men are advised to thoroughly rinse the penis and the fold of the foreskin before collecting material. For the study, it is necessary to collect the average portion of the first morning urine (that is, the initial and last portions are flushed down the toilet). Urine is collected in a special sterile disposable container, which is given to the laboratory before the analysis or purchased at the pharmacy. Some laboratories can purchase a transport tube containing a preservative (usually boric acid). When collecting urine, you should not touch the inner wall of the container.

Material for bacteriological examination in infants is collected using a urine bag, which can be purchased at a pharmacy, and then poured into a sterile container.

To collect urine for culture, you should not use glass jars or household plastic containers, since it is usually not possible to ensure the sterility of such containers at home. In addition, non-sterile disposable containers should not be used.

The material must be delivered to the laboratory no later than two hours after collection.

Normally, there are no microorganisms in the urinary tract, the only exception being the distal urethra, which is populated by microflora from the skin of the perineum.

Analysis result

The main task of the analysis is to identify microorganisms in urine and determine their etiological role. The type of infectious agent, the degree of bacteriuria, the detection of microorganisms in repeated studies, etc. are taken into account.

Bacterial culture of urine is carried out on nutrient media using a bacteriological loop, swab or spatula. Normally, there is no growth of microorganisms; signs of microbial growth indicate the presence of a bacterial infection in the urine, i.e. bacteriuria.

The degree of bacteriuria allows for differential diagnosis of the infectious process from contamination of urine with normal microflora. Thus, bacteriuria up to 10 3 microbial cells in 1 ml of urine usually indicates the absence of an infectious-inflammatory process and, as a rule, is determined in the case of urine contamination; with bacteriuria 10 4, the result is questionable and there is a need for a repeat study; 10 5 or more - infectious and inflammatory process.

In order to control the therapy, the change in the degree of bacteriuria is assessed; its decrease indicates the effectiveness of the drugs used. However, when deciphering a urine test for bacterial culture, it should be taken into account that in some cases (during antibacterial therapy, low pH values ​​and/or specific gravity of urine, impaired passage of urine, etc.), a low degree of bacteriuria can be determined in the presence of a pathological process. For this reason, the identification of infectious agents found in urine is also important (repeated isolation of bacteria of the same species usually indicates the presence of infection).

Unlike clinical urine analysis, bacteriological analysis is not carried out for preventive purposes, but is prescribed if there are signs of a urinary tract infection.

The detection of a monoculture or association of microorganisms in the urine is of diagnostic importance. In acute infectious and inflammatory processes, a monoculture is usually isolated against the background of high-grade bacteriuria, and in chronic ones, associations of microorganisms are usually isolated against the background of low-grade bacteriuria.

In addition to identifying the infectious agent, a urine culture test can determine the antibiotic sensitivity of isolated strains of microorganisms.

To make a diagnosis, data from not only urine culture, but also other studies are usually used, and clinical signs of pathology are also taken into account.

Video from YouTube on the topic of the article:

[40-122 ] Laboratory screening for urinary tract and kidney infections

1110 rub.

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A comprehensive laboratory test aimed at the primary detection of an infectious process in the kidneys and urinary tract.

Synonyms Russian

Urinary tract and kidney infections; urethritis, cystitis, ureteritis, pyelonephritis; screening examination.

English synonyms

Urinary tract and kidney infections; urethritis, cystitis, ureteritis, pyelonephritis; screening tests.

What biomaterial can be used for research?

The first portion of morning urine, the middle portion of morning urine.

How to properly prepare for research?

• Avoid (in consultation with your doctor) taking diuretics for 48 hours before collecting urine.
• For women, the study is recommended to be carried out before menstruation or 2-3 days after its end.

General information about the study

The kidneys and urinary tract belong to the excretory system and play a role in maintaining homeostasis in the human body and the secretion of urine. To the main vital important functions kidney functions include excretory, regulation of water-salt metabolism and acid-base balance, endocrine function, regulation of blood pressure and erythropoiesis. The urinary tract or urinary organs include the renal calyces, pelvis, ureters, bladder, and urethra.

For the initial diagnosis of infectious processes in these organs, the following laboratory diagnostic tests and methods can be used: general urine analysis, microscopy of urinary sediment and bacteriological method of urine culture to verify the causative agent of the infectious process. Urine examination is recommended to be carried out in two portions of urine, which allows us to initially suggest the localization of the infectious and inflammatory process. Pathological changes in the first portion of urine may indicate the presence of an inflammatory process in the middle and lower parts of the urethra (urethritis). A shift in indicators in the second portion may be an indicator of a pathological infectious process in the upper parts of the urethra and bladder, which leads to urethritis or cystitis. Changes in the second portion of urine in men are characteristic of inflammatory diseases of the prostate and seminal vesicles. Also, changes in laboratory parameters suggest damage to the ureters and kidneys with the formation of ureteritis and pyelonephritis, respectively.

General urine analysis with microscopy of urinary sediment is a set of diagnostic tests that allow you to evaluate the general properties of urine, its physicochemical properties, the content of metabolic products, and identify the qualitative and quantitative content of a number of organic compounds. They allow us to judge the functional state of the kidneys, urinary tract, general metabolic processes, and the presence of infectious and inflammatory processes.

The development of inflammatory and infectious processes in the kidneys and urinary tract can be assumed based on the following indicators. A change in the clarity and color of urine to a whitish tint or the presence of a white sediment may indicate the presence of leukocytes, bacteria, or fungi. A shift in the acid-base reaction of urine to the alkaline side (pH 7.0-9.0) is associated with a urinary tract infection; it occurs due to the fact that microorganisms hydrolyze urea.

An increase in the number of leukocytes, less often erythrocytes, in general analysis urine and microscopic examination of urinary sediment is an important indicator of damage to the kidneys and urinary tract. Normally, a small number of leukocytes are found in the urine of healthy people. In a laboratory study of urine, two conditions are distinguished: leukocyturia and pyuria, which are the most important pathological signs of inflammation of the kidneys and urinary tract. Leukocyturia is an increased content of leukocytes while maintaining urine transparency. Pyuria is reflected by cloudiness of the urine and the presence of leukocytes in all fields of view during microscopy of urine sediment. The appearance of red blood cells in the urine (hematuria) can also accompany urinary tract and kidney infections. For example, with pyelonephritis, a third of patients may experience hematuria. Detection of leukocyturia and bacteriuria in a patient is diagnostically valuable. During sediment microscopy, the detection of leukocyte, granular casts may be signs of acute pyelonephritis, exacerbation of chronic pyelonephritis, or kidney abscess.

Increased amounts of bacteria and nitrites in the urine indicate the presence of a bacterial infection of the kidneys and/or urinary tract. It is important to note the importance of these tests in the screening diagnosis of chronic pyelonephritis. This is a common disease, which in 30-40% of cases can be asymptomatic, leading to a severe course, the development of complications and the difficulty of selecting effective treatment.

In healthy people, the urinary system is sterile and the minimum amount of bacteria from the surface of the lower parts of the urethra does not exceed 1 * 10 4 / ml. This amount of bacteria does not convert the nitrates present in normal urine into nitrites. Therefore, the reaction to nitrites is normally negative.

Bacteriuria is a condition in which the content of bacteria in the urine is more than 1 * 10 5 / ml. Bacteria found in urine are most often represented by gram-negative flora. They can enter the urinary tract by ascending infection or hematogenously. These include microorganisms belonging to the genus Klebsiella, Proteus, Enterobacter, Salmonella, Pseudomonas, Citrobacter, staphylococci, streptococci, enterococci. Escherichia coli is often found. Ascending infection is often complicated by the development of pyelonephritis. This disease is more common in women and older men. In pregnant women, bacteriuria is detected five times more often than in non-pregnant women. In 70% of pregnant women, the cause of pyelonephritis is Escherichia coli bacteria. Glucosuria contributes to the aggravation and development of ascending urinary tract and kidney infections. Risk groups for the development of pyelonephritis are patients with urethritis, cystitis, pyelocystitis, ureteritis, urolithiasis, patients after instrumental and surgical intervention on the urinary tract. Yeast-like fungi of the genus Candida may also play a role in the development of kidney and urinary tract infections.

It should be noted that to diagnose bacteriuria, the average portion of the first morning urine is examined. It is important to thoroughly clean the external genitalia and use sterile containers to collect urine to exclude false-positive results. Bacteria such as gonococci, streptococci and mycobacterium tuberculosis do not form nitrites. Therefore, the reaction to nitrites in in this case will be negative. In children infancy urine does not contain nitrites. Therefore, bacteriological examination of urine is recommended to confirm a bacterial infection.

Bacteriological examination of urine (urine culture for microflora) using specific nutrient media is recommended for adults and children to confirm kidney and urinary tract infections, to identify and isolate the causative agent of the infectious process. This is a microbiological study that allows you to determine the composition of the microflora of the urine being tested and identify opportunistic and pathogenic microorganisms. To select effective therapy against a specific pathogen, a subsequent determination of sensitivity to antibiotics is carried out. When microorganisms that make up the normal microflora or opportunistic microorganisms are detected in a titer less than diagnostic, sensitivity to antibiotics and bacteriophages is not determined, since this amount is not significant and does not require treatment with antimicrobial drugs.

What is the research used for?

• For the diagnosis of infectious processes of the urinary tract: urethritis, cystitis, ureteritis;
• for the diagnosis of infectious processes of the kidneys: acute and chronic pyelonephritis, kidney abscess;
• to determine the causative agent of the infectious process and select effective antimicrobial therapy.

When is the study scheduled?

• For symptoms of infectious and inflammatory processes of the kidneys and urinary tract: painful urination, pain in the lower abdomen, predominance of nighttime diuresis over daytime, anuresis, persistent low-grade fever, fatigue, weakness, headaches, weight loss, nausea;
• with an asymptomatic course of the disease, if a sluggish or chronic infectious process is suspected;
• patients after instrumental and surgical intervention on the urinary tract;
• men with prostate adenoma and prostatitis;
• patients with urolithiasis;
• patients with chronic diseases, hypertension, diabetes;
• children over 4 years of age for medical examination purposes;
• patients over 70 years old;
• women after premature birth, miscarriage, abortion.

What do the results mean?

Reference values

Color: from straw yellow to yellow.

Transparency: transparent.

Protein: not detected or less than 0.1 g/l.

Glucose: not detected.

Bilirubin: not detected.

Urobilinogen: not detected or traces.

Ketone bodies: not detected.

Nitrites: not detected.

Reaction to blood: not detected.

Specific gravity: 1.003 - 1.030.

Reaction: 5.0 - 7.5.

Urine sediment examination

• Bacteria: not detected or a small amount.

• Epithelium is flat

• Leukocytes

• Red blood cells: 0 - 11 cells/µl.
• Cylinders: none.
• Mucus: small amount.
• Crystals (oxalates): none.

2. Sowing for aerobic and facultative anaerobic flora

A conclusion is issued about the detection / non-detection of normal and opportunistic flora.

Reasons for detection - growth of flora:

• acute or chronic pyelonephritis;
• kidney abscess;
• ureteritis;
• cystitis;
• urethritis.

The result of the bacteriological examination is positive - the presence of growth of colonies of microorganisms on a liquid or solid nutrient medium.

Reasons for non-detection - lack of flora growth:

• absence of infectious process;
• false negative result.

The result of the bacteriological examination is negative - no growth of colonies of microorganisms.



General urine analysis with sediment microscopy

Serum albumin

Serum creatinine (with GFR determination)

Urea in serum

Total protein in whey

Laboratory examination for pyelonephritis

Who orders the study?

Infectious disease specialist, general practitioner, therapist, urologist, nephrologist, pediatrician, obstetrician-gynecologist, surgeon.

Literature

1. Dolgov V.V., Menshikov V.V. Clinical laboratory diagnostics: national guidelines. – T. I. – M.: GEOTAR-Media, 2012. – 928 p.
2. Mironova I.I., Romanova L.A., Dolgov V.V. General clinical examinations: urine, feces, cerebrospinal fluid, ejaculate. – M.-Tver: Triada Publishing House LLC, 2005. – 206 p., 218 ill.
3. Chernecky S.S. Laboratory tests and diagnostic procedures / S.S. Chernecky, B.J. Berger; 5th ed. – St Louis: Saunders Elsevier, 2008. – 1232 p.
4. Fauci, Braunwald, Kasper, Hauser, Longo, Jameson, Loscalzo Harrison’s principles of internal medicine, 17th edition, 2009.

Presence of bacteria in freshly released urine due to an infectious inflammatory process in the organs of the urinary system or the male genital organs. Bacteria can enter the urine in various ways: descending - from inflammatory foci in the kidneys, bladder, prostate gland or glands of the posterior part of the urethra, and ascending - during instrumental interventions (catheterization, cystoscopy, bougienage, stone crushing, etc.). It has been established that microbes do not penetrate from the bloodstream into the urine through intact kidneys. Bacteria can multiply both in the affected organ (for example, in kidney tissue with pyelonephritis) and in urine, which is a good nutrient medium. In this case, the degree of bacteriuria due to the proliferation of bacteria in the renal pelvis and ureter increases only with stasis of urine in the upper urinary tract (complete or partial occlusion of the ureter, etc.). The proliferation of microorganisms in the bladder occurs with any source of bacteriuria (pyelonephritis, cystitis), and the more it increases, the longer the infected urine is contained in the bladder, i.e., the less often the patient empties the bladder. Pathological processes that lead to impaired bladder emptying (prostate adenoma, urethral stricture, etc.) are important.

Bacteriuria is found in approximately 10% of healthy men and women, since microflora often grows in the anterior section of the urethra. Therefore, bacteriuria caused by an inflammatory process in the urinary tract must be distinguished from urine contamination by constantly vegetative microflora of the urethra. Bacteriuria can be detected by culturing urine obtained during spontaneous urination on special nutrient media, determining the bacterial content separately in the initial and middle portions of urine. The ideal method to exclude urethral microbes from entering the urine is suprapubic puncture of the bladder. However, this method cannot be widely used due to its complexity. Quantitative methods for determining bacteriuria, introduced into clinical practice by Kass (Kass, 1956), showed that during a purulent-inflammatory process in the kidneys or urinary tract there are 100,000 or more microbes in 1 ml of urine, while when it is contaminated with microflora of the urethra, the degree of bacteriuria significantly less.

The degree of bacteriuria can be determined: 1) by inoculating urine on various nutrient media; 2) microscopy of urine sediment using light-field (FK-4) and dark-field (MFA-2) phase-contrast devices; 3) using chemical reagents. The simplest and most accurate method turned out to be a simplified method of inoculating urine with a sterile platinum loop on agar in certain sectors of a Petri dish according to Gould (Gould, 1965). Currently, three methods for detecting bacteriuria using chemical tests are used in clinical practice. The nitrite test, proposed by Griess (1879), is based on the reduction of nitrates contained in urine under the influence of bacteria into nitrites. The TTX test, proposed by Simmons and Williams (1962), is based on the reduction of colorless triphenyltetrazolium chloride to red triphenylformazan in the presence of microbes in the urine. Braude's test (Braude, 1959) is based on the release of oxygen bubbles after adding 3% hydrogen peroxide to urine under the influence of catalase secreted by bacteria.

A high degree of bacteriuria is not observed in all stages of acute illness, much less: on average, in 60-70% of patients. Urine culture during bacteriuria can be sterile due to the formation of protoplasts and L-forms of bacteria, since osmotically fragile protoplasts and L-forms of bacteria, formed under the influence of antibiotics, antibodies, complement and lysozyme, do not have a dense cell wall and can only maintain vital activity in an environment with increased osmotic pressure.

To identify these forms of bacteria, the nutrient medium on which urine is inoculated should be stabilized osmotically by adding sucrose.

In some cases, bacteriuria occurs without clinical signs of damage to the organs of the urinary system (asymptomatic bacteriuria), in others it is combined with symptoms of cystitis, pyelonephritis, prostatitis, urethritis. Urine may be cloudy due to large quantity microbes; When standing or centrifuging, a sediment forms with difficulty or does not form at all. The reaction of urine varies depending on the nature of the microflora.

Urine culture

A urine test for the degree of bacteriuria is needed to determine the presence of pathogenic bacteria in the urinary tract. Normally, a person's urine in the urinary tract is sterile, but micro...

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Description of the study

Preparing for the study:

• Before collecting urine hygiene procedures so that microorganisms from the external genital tract do not enter the material. Women should not be menstruating during this time.
• For the study, take an average portion of urine. To do this, flush a small amount of urine down the toilet, then collect the middle part into a special container, and flush the rest of the urine down the toilet as well.
• Do not take diuretics for 2-3 days
• Deliver tests for research within an hour

Test material: Urine

Urine analysis for the degree of bacteriuria needed to determine the presence of pathogenic bacteria in the urinary tract. Normally, in humans, urine in the urinary tract is sterile, but microorganisms can enter the urine from the perineum and lower third of the urethra without causing inflammation. A urine test to determine the degree of bacteriuria is prescribed to all patients with inflammatory diseases of the urinary tract. All microorganisms, according to their ability to cause infectious diseases, are divided into:

• Pathogenic (should not be normal, capable of causing disease)
• Non-pathogenic (normally present in the body and do not cause disease)
• Opportunistic (normally released in small quantities, they begin to actively reproduce under certain conditions)

By analyzing urine for the degree of bacteriuria, the doctor identifies the presence of infectious inflammation and prescribes the necessary treatment.

This analysis allows you to identify the level of bacteriuria, determine the cause of inflammatory diseases of the urinary tract, and also monitor the cure after treatment.

Method

The sector sowing method is used. With this method, the test material (urine) is placed on a nutrient medium, then the number of microbial cells in 1 ml is determined. the material being studied.

Reference values ​​- norm
(Degree of bacteriuria, urine)

Information regarding the reference values ​​of indicators, as well as the composition of the indicators included in the analysis, may differ slightly depending on the laboratory!

Norm:

• No bacterial growth detected - normal
• Bacterial growth detected - 10 3 CFU/ml - such bacterial growth does not usually cause an inflammatory process
• Bacterial growth of 10 4 CFU/ml was detected - this result is usually assessed as doubtful, it is recommended to repeat the analysis
• Bacterial growth of 10 5 CFU/ml was detected - such bacterial growth usually causes the development of an inflammatory process

Indications

• Inflammatory diseases kidneys and urinary tract
• Control after treatment, 5-7 days after discontinuation of antibiotics

Increasing values ​​(positive result)

• An increase in values ​​indicates the presence of an infection in the urinary tract. An assessment of the degree of pathogenicity of the identified microorganism and its relationship with the presence of inflammatory changes is carried out by a doctor, taking into account clinical data

Lower values ​​(negative result)

• A decrease in analysis values ​​indicates negative result and absence of inflammatory process