Epidemiological studies The incidence of urinary tract infections is 9 times higher in women than in men. Most women will have two or more urinary tract infections during their lifetime. The incidence of UTIs increases with age by approximately 1% every 10 years, and approximately 10% of women over the age of 70 have UTIs. Pathogenesis The ability of bacteria to adhere to the urinary epithelium is the main cause of urinary tract infections. Most bacteria first settle in the rectum and then multiply around the urethra and distal urethra to enter the bladder through the urethra. Many genetic, biological and behavioral factors have been implicated. Local environmental changes in the vagina, such as pH and cervicovaginal antibodies, urine and bladder defense mechanisms play an important role in susceptible individuals. Host inflammation and immune response determine the outcome of clinical UTI. The current study found that the ability of E. coli with P-type hairs to multiply is a very risky causative factor for acute pyelonephritis. In contrast to pyelonephritis, the pathogenesis of cystitis is poorly understood, and the bacterial characteristics of E. coli causing cystitis are not known, nor are they distinguished from the pathogenic strains that cause pyelonephritis. Only erythropoietin is known to be present. Recent data suggest that sexual intercourse, spermicide and a history of recurrent UTIs are risk factors. Recent antibiotic use affects the vaginal flora and is also a causative factor for recurrent UTIs. Frequency of sexual intercourse was the most risky causative factor in the multifactorial analysis. Other factors included spermicide use in the past year and having a new sexual partner, first UTI occurring before age 15, or a family history of UTI Recurrent UTI was not associated with pre- or post-coital urination patterns, frequency of urination, delayed urination habits, wiping patterns, douching, use of hot tubs, wearing tight leggings, or body mass index. In healthy postmenopausal women, several studies have shown that estrogen deficiency (genitourinary atrophy) is a risk factor for urinary tract infections, and Raz and Stamm demonstrated that intravaginal estrogen application normalizes vaginal flora and reduces the recurrence of UTIs. The recurrence of UTI after menopause is also strongly associated with changes in bladder emptying mechanisms and physiological factors. Recurrent UTI Pelvic abnormalities may also contribute to UTI recurrence. The urethra-to-anus distance was found to be significantly shorter in patients with recurrent UTI compared with controls (4.8 and 5.0 cm, respectively, P=0.03). There were no differences in urethral length, residual urine, and voiding patterns (e.g., peak urinary flow rate, peak urinary flow time) between the case and control groups. It is hypothesized that pelvic anatomy plays an important role in the recurrence of urinary tract infection, especially among patients without exogenous risk factors. Clinical diagnosis A complete medical history was collected, including history of urinary stones, diabetes mellitus and other urological diseases, urological procedures and instrumentation. The patient’s history of previous infections, such as the frequency of infection, whether it is related to sexual intercourse, and the method of contraception, should be detailed. The results of previous bacterial cultures, treatment medications, and treatment effects are helpful in the analysis of recurrent urinary tract infections. Physical examination should be performed according to the condition, with special attention to the pelvis and perineum, to exclude urinary tract pathology, such as urethral meatus, stricture, prolapse, and vaginal pathology, etc. If necessary, vaginal secretions should be taken for examination. Clinical manifestations include frequency, urgency, painful urination, difficulty in urination, pain in the suprapubic area or lower abdomen, hematuria or cloudy urine, etc. Laboratory diagnosis Routine urinalysis and urine culture nCollect urine in the correct way, telling the patient to keep the labia completely apart when collecting urine. For urine culture, the vulva should be washed with wet gauze, and then a midstream urine specimen should be taken. Disinfectants are not needed for washing because they can contaminate the specimen and cause false-negative results. Urinalysis for acute cystitis will show bacteriuria, pyuria, and hematuria. It is now proposed that a urine culture with a colony count (CFU) of 102 CFU/ml or more in symptomatic patients will confirm the diagnosis. Although urine cultures can determine drug susceptibility, this is not actually done clinically and is not necessary. In many patients, treatment is completed before the urine culture results are available. Pre-treatment urine cultures and sensitivity testing are necessary if the patient has recently used antibiotics, has had symptoms of urinary tract infection for more than 7 d, is >65 years of age, has diabetes mellitus, or is pregnant. CT and ultrasound can rule out stones, obstructive disease, etc. Most patients do not have anatomic abnormalities and therefore do not require routine urologic examination. Persistent hematuria should be followed by IVP, cystoscopy, etc. after the infection has cleared. Urinary tract infections should be differentiated from vaginitis, infections due to sexually transmitted diseases, and urethral discomfort due to non-inflammatory lesions. Treatment of uncomplicated cystitis Uncomplicated cystitis occurs in women with normal urinary tract anatomy and function. The bacteria are usually sensitive to antibiotics and a short course of treatment is effective. Prevention of recurrent urinary tract infections There are two types of recurrent urinary tract infections: reinfection: an infection caused by a different bacterium, which usually occurs 2 weeks after the previous infection and within 5 months. The other is bacterial persistence: the pathogenic bacteria are the same as the initial infection, and the infection occurs in a short interval. Most recurrent urinary tract infections are reinfections, and it is rare to see a bacterial infection that persists through the urinary tract. The correct distinction between the two is important in terms of treatment because patients with reinfection require prolonged treatment. The persistence of bacteria requires surgical treatment for certain abnormalities.