Urinary Tract Infections

Urinary tract infections – the condition of infection of the urinary tract with microflora, which causes its inflammation. In Russia, the prevalence of UTI is 1000 cases per 100 thousand people per year, it is the most common infection. UTIs is 50 times more common in women than in men. Most often there is acute uncomplicated cystitis, somewhat less often-uncomplicated pyelonephritis. Repeated UTIs develop in 20-30% of women of pre-menopausal age. By the age of 50, the frequency of UTIs in men and women is compared. The cost of UTI treatment in the United States is $ 1.6 billion per year, and one episode of acute cystitis is $ 40-80. Nosocomial UTIs are the cause of death in 50 thousand patients annually.

Classification. There is an infection of the upper (pyelonephritis) and lower urinary tract (cystitis, prostatitis, urethritis) by the presence or absence of symptoms (symptomatic or asymptomatic bacteriuria), by the origin of the infection (community-acquired or nosocomial, complicated and uncomplicated. Uncomplicated UTIs are characterized by the absence of outflow disorders. Complicated infections are accompanied by functional or anatomical abnormalities of the upper or lower urinary tract. Risk factors for complicated UTIs are anatomical and functional disorders, congenital pathology, vesicoureteral reflux, sexual activity, gynecological surgery, urinary incontinence, frequent catheterization; in men, uncircumcised foreskin, homosexuality, benign prostatic hyperplasia, intravesical obstruction. Metabolic and immunological disorders, foreign bodies in the urinary tract, concretions, urinary disorders, elderly age of the patient, spinal cord lesions and multiple sclerosis, diabetes mellitus, neutropenia, immunodeficiency, pregnancy, instrumental research methods contribute to UTI. In men, most UTIs are considered complicated. Complicated UTIs are predominantly nosocomial, and complicated forms account for 45% of all UTIs in adult outpatients. UTI is complicated by urolithiasis, diabetes mellitus, kidney cysts, and nephroptosis. Among nosocomial infections, about 80% of UTIs are associated with bladder catheterization. The catheter should be removed within 4 days of catheterization.

Etiology. In uncomplicated UTIS-E. Coli; in complicated UTIs, Proteus, Pseudomonas, Klebsiella, fungi are more common.

The source of uropathogenic microorganisms is the intestine, the anal region, the vestibule of the vagina and the periurethral region. Inflammation most often develops in conditions of impaired outflow of urine in combination with a decrease in the overall reactivity of the body. UTI is characterized by microbial colonization in the urine of more than 104 colony-forming units (COE) of microorganisms in 1 ml of urine and (or) microbial invasion with the development of an infectious process in any part of the urethra from the external opening of the urethra to the cortical substance of the kidneys.

There are the following types of UTIs: severe bacteriuria, minor bacteriuria, asymptomatic bacteriuria, and contamination. UTI is verified when the number of microbial bodies exceeds 105 COE in 1 ml in two consecutive portions of freshly released urine and confirmed by microscopic examination of the urine in order to exclude vaginal contamination, in which a false positive result is often observed. A decrease in diuresis and a lack of injected fluid contribute to the proliferation of bacteria. Asymptomatic bacteriuria is quite often detected in routine studies, more typical for older men with benign prostatic hyperplasia.

Contamination refers to two different conditions: bacterial contamination and the moment of infection. Contamination should be considered in cases where there is a small growth of bacteria or several types of bacteria are seeded from the urine. The isolation of more than one microorganism from the urine should always be interpreted with caution and take into account the dominance of any one microorganism, the presence of white blood cells and clinical symptoms.

Diagnostics. A common screening test-a reagent strip with a biochemical reagent-detects the presence of leukocyte esterase (pyuria) and evaluates the reactivity of nitrate reductase. A negative result of the test strip excludes infection. In practice, red blood cells and white blood cells that make up the urinary sediment are lysed at a urine pH greater than 6.0, with low urine osmolarity, and prolonged standing of urine; therefore, false-negative results in urine microscopy are more common than false-positive results in the study of a test strip. Leukocyturia does not always indicate the presence of bacteriuria. The source of white blood cells can be inflammatory processes in the female genital organs, it can persist after the spontaneous or drug-induced disappearance of bacteriuria. Microscopic examination of the urine sediment is mandatory.

The use of phase-contrast techniques facilitates the detection of most cellular elements in comparison with light microscopy. At high magnification (40 times), the detection of 1-10 microorganisms in the field of view determines bacteriuria, and the presence of more than 10 white blood cells in the field of view determines pyuria. Gram staining and acid resistance studies should be performed in patients with UTI symptoms and pyuria when routine urine culture results are negative.

Treatment. The goals of antimicrobial treatment and prevention of UTIs are the eradication of pathogenic microorganisms from the genitourinary system and the prevention of exacerbation or reinfection. The choice of an antibiotic is based on the spectrum of action of the drug, the sensitivity of microorganisms, the pharmacokinetic and pharmacodynamic properties of the antibiotic, and side effects. According to the recommendations of the Federal Guidelines for Physicians, adult patients should be prescribed fluoroquinolones and fosfomycin trometamol (once), children-inhibitor-protected beta-lactams and oral cephalosporins of the II—III generation. In pregnant women, the first-line drugs are cephalosporins of the I—III generation, fosfomycin trometamol (once), an alternative to which can be amoxicillin (including with clavulanic acid, nitrofurantoin and cotrimoxazole).

In most cases, infection of the lower urinary tract is combined with neuromuscular disorders of the smooth muscle elements of the urinary tract and pelvic organs, in this case, the addition of antispasmodics to complex therapy is indicated. Effective herbal preparation Cystone (2 tablets 2 times a day). The extracts of saxifrage, strawberries and other plant components contained in it have a pronounced antimicrobial, anti-inflammatory, antispasmodic and diuretic effect; the remaining components reduce the risk of stones in the urinary tract; antimicrobial action is manifested in any acidity of the urine. The drug is effective in the resistance of microorganisms to antibiotics.

In most cases, antibacterial therapy is indicated, except for asymptomatic bacteriuria. The goals of antibacterial therapy: rapid resolution of symptoms, eradication of pathogens, reduction of relapses and complications, reduction of mortality. The success of treatment is largely determined by the correction of urogenital pathology. In asymptomatic bacteriuria, antibacterial therapy should only be prescribed:

1) Pregnant women, when due to dilatation of the ureters, it is possible to develop an ascending infection, which is associated with a high risk of premature termination of pregnancy (it reduces the frequency of pyelonephritis by 75%);

2) Patients who are supposed to have an intervention on the gastrointestinal tract;

3) Dialysis patients who are supposed to have a kidney transplant;

4) Before performing invasive diagnostic urological procedures;

5) During immunosuppression.

In elderly patients with asymptomatic bacteriuria, antimicrobial therapy usually does not prevent symptoms. An antibiotic is not prescribed for empirical therapy if the level of resistance of the main pathogens to it exceeds 10-20%. Due to the high level of microbial resistance, ampicillin and cotrimoxazole cannot be recommended for the empirical treatment of UTIs, the drug of choice is fluoroquinolones. Fluoroquinolones have a bactericidal effect, have a wide range of antimicrobial activity, including against multiple-resistant strains of microorganisms, have high bioavailability when taken orally, have a fairly high half-life, create a high concentration in the urine, well penetrate the mucous membranes of the genitourinary tract and kidneys. The effectiveness of fluoroquinolones in UTI is 70-100%, these drugs are well tolerated, the frequency of side effects is 2-4%. The optimal duration of treatment for acute uncomplicated cystitis according to the results of meta-analysis is 3 days. Fluoroquinolones are the drugs of choice for the treatment of complicated and nosocomial UTIs (ciprofloxacin). Bacteriological efficacy – 84%, clinical-90%, the course of treatment should be at least 7-14 days 500 mg 2 times a day.

Half of the women after the first episode of cystitis develop a relapse within a year. The frequency of recurrence is associated with the anatomical and physiological characteristics of the female body (short and wide urethra, proximity to the natural reservoirs of infection-the anus, vagina; adhesion of gram – negative microorganisms to the cells of the urethral epithelium and bladder; frequent concomitant gynecological diseases, hormonal disorders (vaginal dysbacteriosis), genetic predisposition, anomalies in the location of the external urethra, the presence of sexually transmitted infections).

Unjustified and irrational antibacterial therapy contributes to the chronization of the process. STIs (sexually transmitted infections – chlamydia, trichomoniasis, syphilis, ureaplasmosis, genital herpes) are detected in almost a third of patients with pyelonephritis and half with cystitis. Pathogens of urogenital infections are detected by PCR (polymerase chain reaction) method.

Treatment of NIMP (uncomplicated infection of the lower genital tract) should be etiological and pathogenetic and should include antibacterial therapy lasting up to 7-10 days, the choice of drugs is carried out taking into account the isolated pathogen and the antibioticogram, preferably the appointment of antibiotics with a bactericidal effect. The drugs of choice for non-obstructive pyelonephritis are fluoroquinolones and nitroimidazoles; for recurrent cystitis-fluoroquinolones, fosfomycin trometamol (3 g once every 10 days for 3 months), bacteriophages. Complex treatment should also include as indicated:

1) Correction of anatomical disorders;

2) STI therapy, in which the drugs of choice are macrolides (josamycin, roxithromycin, azithromycin), tetracyclines (doxycycline), fluoroquinolones (moxifloxacin, levofloxacin, ofloxacin), antiviral agents (acyclovir, valacyclovir), treatment of sexual partners;

3) Postcoital prophylaxis (cotrimoxazole 200 mg, trimethoprim 100 mg, nitrofurantoin 50 mg, cephalixin 125 mg, norfloxacin 200 mg, ciprofloxacin 125 mg, fosfomycin trometamol 3 g);

4) Treatment of inflammatory and dysbiotic gynecological diseases;

5) Correction of unfavorable hygienic and sexual factors;

6) Correction of immune disorders;

7) Local therapy;

8) The use of hormone replacement therapy in patients with estrogen deficiency.

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