What causes urinary tract infections?

Bacteriological studies have shown that the spectrum of microflora depends on many factors:

• age of the child;
• gender;
• gestational age at the time of birth of the child;
• period of the disease (onset or relapse);
• conditions of infection (community-acquired or hospital-acquired);
• the presence of anatomical obstruction or functional immaturity;
• resistance of the child's body;
• state of the intestinal microbiocenosis;
• region of residence;
• methods and timing of urine cultures.

In various conditions of occurrence of urinary tract infections, Enterobacteriaceae predominate, primarily Escherichia coli (up to 90% of studies). However, in hospital patients, the role of enterococci, Pseudomonas aeruginosa, Klebsiella, and Proteus increases. According to multicenter studies, the structure of urine microflora in children with community-acquired urinary tract infection is uniform, although the etiologic role of individual bacterial species may differ significantly from the average. In most cases, urinary tract infection is caused by one type of microorganism, but with frequent recurrence of the disease and developmental anomalies of the urinary system, microbial associations can be detected. Among children with recurrent pyelonephritis, about 62% have mixed infection. There is a hypothesis suggesting a connection between urinary tract infection and intrauterine Coxsackie virus infection, as well as influenza viruses, parainfluenza, RS viruses, adenoviruses, cytomegalovirus, herpes simplex virus types I and II. Most nephrologists consider viruses as a factor contributing to the addition of bacterial infection.

Along with bacteria, the development of urinary tract infection may be caused by urogenital chlamydia, ureaplasmosis and mycoplasmosis, especially in children with vulvitis, vulvovaginitis, urethritis and balanoposthitis. Fungal infection of the urinary tract is usually found in children with immunodeficiency conditions (premature, with hypotrophy, intrauterine infection, malformations, those who have received immunosuppressive therapy for a long time), in whom associations of bacteria with fungi are more typical.

Predisposing factors for urinary tract infection:

• functional disorders of urodynamics associated with hypotension of the urinary system;
• neurogenic bladder dysfunctions;
• developmental anomalies of the ureters and urinary system;
• vulvitis, balanoposthitis;
• vesicoureteral reflux;
• ureterocele, pyelourethral obstruction;
• decreased resistance of the body;
• intestinal infections;
• constipation, disruption of intestinal biocenosis;
• catheterization of the urinary bladder, manipulation of the urinary tract;
• hypovitaminosis;
• allergic dermatitis.