Bacteriuria : Causes, Symptoms, Diagnosis & Treatment

• Classification
• Causes Of Bacteriuria
• Violation Of Preparation For Analysis
• Asymptomatic Bacteriuria
• Urinary Tract Infections
• Genital Infections
• Risk Factors For Bacteriuria
• Diagnostics
• Correction
• Forecast

Bacteriuria is a laboratory symptom that characterizes the presence of bacteria in the urine. Most often, this indicates a urinary tract infection (kidney, bladder), but may be a harmless laboratory finding. Clinical manifestations can be varied - from an absolutely asymptomatic course to pronounced signs (fever, back pain, urination disorders). The presence of bacterial flora in the urine is investigated in several ways - physicochemical, bacteriological, etc. Correction of bacteriuria is carried out by the appointment of antibacterial drugs.

Classification

Depending on the number of bacteria, some experts conventionally distinguish between minor and severe bacteriuria. In clinical practice, only one classification is used to determine the tactics of treating a patient:

• Asymptomatic bacteriuria. It is characterized by the detection of bacteria in the urine in the absence of any complaints and other laboratory signs of urinary tract infections (leukocyturia, etc.) in the patient.
• symptomatic bacteriuria. A combination of clinical symptoms and detection of bacteria in a urine sample.

Causes of bacteriuria

Violation of preparation for analysis

A fairly common cause of bacteriuria. Incorrect preparation for a urinalysis, especially failure to perform or careless toileting of the external genitalia, can lead to false-positive results. It is also considered incorrect to pass a urine test during menstruation. Blood, being a breeding ground for bacteria, creates a favorable environment for their reproduction.

When using non-sterile utensils for urine collection, contamination of the sample with foreign flora is possible. To pass urine to a bacteriological laboratory for culture, it is recommended to use special test tubes with preservatives (boric acid, sodium formate, and borate), which stabilize the bacterial composition of urine.

Asymptomatic bacteriuria

Detection of bacterial flora in the urine without clinical and laboratory signs of infectious and inflammatory diseases of the urinary tract occurs in 1-5% of healthy women of premenopausal age, in 2-10% of pregnant women, in 4-20% of healthy elderly men and women. Asymptomatic bacteriuria is rarely observed in young healthy men.

Such age-sex characteristics of bacteriuria are associated with the anatomical and physiological characteristics of the female urogenital system, hormonal changes during pregnancy and menopause, as well as with age-related changes in local immunity. Asymptomatic bacteriuria is a benign condition and does not require any intervention, except in some patients who are at high risk for developing urinary tract infections.

Bacteriuria

Urinary tract infections

The most common cause of bacteriuria is acute, chronic, and recurrent urinary tract infections. The causative agents of these pathologies are predominantly gram-negative enterobacteria - E. coli, Klebsiella, and Proteus. Very rarely, infections of the genitourinary system are caused by gram-positive flora - staphylococci, and enterococci. Infection occurs in several ways. The ascending path is recognized as the most common - through the urethra to the bladder and/or kidneys.

The hematogenous or lymphomatous way is less often possible. This option occurs when there is an additional focus of infection in the body - pneumonia, infections of the oral cavity, ENT organs. The degree of bacteriuria can be different, it does not correlate with the severity of the disease and disappears almost from the first days of treatment with properly selected antibacterial drugs.

• Pyelonephritis. This is an infectious inflammation of the pyelocaliceal system of the kidneys with the involvement of interstitial tissue. It develops mainly in young women (5-6 times more often than in men).
• Cystitis. Inflammation of the mucous membrane of the bladder. A single episode of cystitis occurs in half of the women worldwide.
• Nonspecific urethritis. Inflammation of the urethra, on the contrary, is more typical for men due to the longer and narrower urethra.

genital infections

Bacteriuria in infections of the male and female genital organs is very rare. They are caused by nonspecific conditionally pathogenic gram-negative and gram-positive flora (E. coli, enterococci, anaerobic bacteria) and often occur together with cystitis and urethritis. The severity of bacteriuria is in no way related to the intensity of the inflammatory process.

• Infections of the male genital area. These include bacterial prostatitis (occupies about 10% of all cases of inflammation of the prostate), and extremely rarely, orchitis and epididymitis (inflammation of the testicle and its epididymis), balanoposthitis (inflammation of the head and foreskin of the penis).
• Infections of the female genital area. These infections include inflammation of the vagina and/or vulva (vaginitis, vulvovaginitis), and cervix (cervicitis).

It should be noted that in the case of infectious diseases of the genital organs caused by bacteria that provoke sexually transmitted diseases, such as chlamydia, mycoplasmosis, gonorrhea, bacteriuria does not develop. These infections are diagnosed by other special research methods.

Risk factors for bacteriuria

This group includes diseases or conditions that contribute to the appearance of microorganisms in the urine:

• Glucosuria: poorly controlled hyperglycemia in diabetes mellitus, long-term use of glucocorticosteroids, various endocrine disorders (Itsenko-Cushing's disease/syndrome, pheochromocytoma, glucagonoma).
• Previously transferred UTI.
• Violation of the outflow of urine: urolithiasis, congenital anomalies in the structure of the urinary system, stenosis of the ureters.
• Reverse reflux of urine: vesicoureteral pelvic reflux.
• The presence of an installed urinary catheter.
• Urine pH shifts to the alkaline side: nutritional features, medications.

Diagnostics

There are several diagnostic methods for detecting bacteriuria. Necessary proper prepare before passing the analysis. In a specific clinical situation, the attending physician chooses a specific study or a combination of methods:

• Microscopy. Detection of bacteria by direct microscopic examination of the sediment from centrifuged urine. The method has an extremely low diagnostic value. Microscopy may reveal signs of improper preparation of the patient - an abundance of diverse flora, a large amount of mucus, and squamous cells.
• Nitrite test. In the process of life, bacteria that colonize the genitourinary tract convert nitrates from food into nitrites. Urinary test strips have a special reagent zone that stains in the presence of nitrites. The test may be false-negative in the absence of nitrates in the patient's diet, infection with bacteria that do not form nitrites (streptococci), and a high content of ascorbic acid in the urine.
• Bacteriological culture. This method is considered the gold standard for diagnosing bacteriuria. In the laboratory, a urine sample is cultured on culture media for certain bacteria. To confirm the diagnosis of "asymptomatic bacteriuria" requires at least 2 cultures with an interval of 24 hours. The disadvantage of the method is the long waiting time for the result - 2 or 3 days.
• Flow cytometry. Some modern automatic analyzers are capable of performing a detailed assessment of the cellular composition of a urine sample, including counting the number of bacteria.

Microscopy, nitrite test, and flow cytometry are considered indicative methods for detecting bacteriuria, and microbiological seeding and - confirming. An important point - in the case of obtaining the growth of bacteria that reach a clinically significant titer (above 10x5 colony-forming units per ml) during inoculation, sensitivity to antibacterial drugs is necessarily determined. This is necessary for the selection of therapy.

In addition to detecting bacteriuria, additional studies are required to differentiate the etiology of its occurrence:

• Analysis of urine. OAM indicators help to find out the cause of bacteriuria. For example, the presence of leukocytes and alkaline urine strongly exclude asymptomatic bacteriuria; an increase in the content of protein, and erythrocytes may indicate pyelonephritis. The detection of transitional epithelium cells by microscopy indicates damage to the bladder or urethra, and the renal epithelium and a large number of cylinders indicate damage to the kidneys.
• ultrasound. On ultrasound of the kidneys with pyelonephritis, an expansion of the CHLS is noted, and anomalies in the structure of the ureters can also be detected. With prostatitis, an ultrasound of the prostate gland reveals an increase in its size, and a decrease in echogenicity. With epididymitis, an ultrasound of the testis visualizes an increase in the epididymis, and diffuse changes.
• Examination by a gynecologist. If you suspect a gynecological disease, you need to consult a gynecologist who examines the genital organs, a bimanual vaginal examination, and a colposcopy. If necessary, a swab is taken from the mucous membranes or separated for cultural examination.
• Urologist examination. Similarly, if indicated, men are scheduled to consult a urologist for digital rectal examination, sampling of prostatic fluid, or ejaculation.

A urine culture on nutrient media

Correction

If bacteriuria is detected, a visit to the doctor is required for correction. Asymptomatic bacteriuria in the vast majority of cases does not require treatment. The exception is pregnant women, patients with urinary catheters, and patients with poorly controlled diabetes mellitus - these patients are indicated for antibiotic therapy. For symptomatic bacteriuria, the following treatment is recommended:

• Pyelonephritis. First-line drugs are penicillins (amoxicillin/clavulanate), and cephalosporins (cefixime, ceftibuten). With strains resistant to them, they resort to fluoroquinolones (levofloxacin, ciprofloxacin), and new generation cephalosporins (cefepime).
• Cystitis. Fosfomycin trometamol or nitrofurans (nitrofurantoin, furazolidone) are used. With recurrent cystitis, preparations based on cranberry extract, D-mannose, and herbal remedies (nephron) are prescribed. Also, with relapses, some experts recommend a lyophilisate of a bacterial lysate of Escherichia coli.
• Genital tract infections. For prostatitis, epididymitis, fluoroquinolones, and macrolides (azithromycin) are used, for vulvovaginitis, and cervicitis - installations with antiseptic solutions and antibiotics active against anaerobic flora (metronidazole, clindamycin).

Forecast

Bacteriuria alone cannot predict clinical outcomes. The prognosis is directly determined by the underlying disease - the most favorable with asymptomatic bacteriuria, cystitis, and urethritis. Often occurring pyelonephritis contributes to the formation of stones in the kidneys. In severe bilateral pyelonephritis, serious life-threatening complications can develop - carbuncle, kidney abscess, hydronephrosis. An extremely rare and fatal consequence of pyelonephritis is urosepsis.