Urinary Tract Infection - Complicated Tổng quan về bệnh

Giới thiệu

Complicated urinary tract infection (UTI) is a form of UTI with an increased chance of a complicated course, possibly extending beyond the bladder, occurring in men, pregnant women, patients with anatomical or functional abnormalities of the genitourinary tract (eg obstruction, incomplete voiding), indwelling urinary catheters, or the presence of an underlying disease that may interfere with host defense mechanisms, which increases the risk of acquiring infection, failing therapy or having recurrent infections. Complicated UTI is also associated with altered microbiology that favors more antimicrobial resistant strains.

Dịch tễ học

Urinary tract infection (UTI) is among the most common bacterial infections, especially in women. Approximately 50% of women experience at least one urinary tract infection during their lifetime, and about 25% of those develop recurrent infections. Urinary tract infection prevalence increases with age, except for a notable peak among females aged 14–24 years. According to the Centers for Disease Control and Prevention, the incidence of complicated UTI is around 1.01%, which is roughly 2.88 million cases annually. Of all UTI cases, complicated UTI can account to as many as 17.6-50.9% of cases. In the United States (US), around 70-80% of complicated UTIs are attributed to indwelling catheters.

Urinary Tract Infection - Complicated_Disease Background

Sinh lý bệnh

The most common route of urinary tract infection is the ascending spread of bacteria from the urethra to the bladder. These bacteria first colonize the periurethral area before entering the urinary tract, where they can multiply and travel up the ureters, potentially causing upper urinary tract infections such as pyelonephritis. Less commonly, upper UTIs develop through hematogenous spread, in which bacteria reach the kidneys via the bloodstream during prolonged bacteremia, often originating from deep-seated infections such as endocarditis. It must be noted that the pathogens causing complicated UTIs follow the same processes; however, in a lot of cases, there is a bladder compromise. In this case, the most common cause of bladder compromise is catheterization

Nguyên nhân

The spectrum of bacteria causing complicated UTI is much larger than that of uncomplicated UTI and is more likely to include antibiotic-resistant organisms. Escherichia coli is the most frequent cause of complicated UTI. Other common uropathogens include Proteus spp, Klebsiella spp, Pseudomonas spp, Serratia spp, Enterococcus spp, and Staphylococcus spp, including methicillin-sensitive S aureus (MSSA) and methicillin-resistant S aureus (MRSA). In CA-UTI, common pathogens in short-term catheterization (<1 week) include E coli and Pseudomonas aeruginosa, whereas those in long-term catheterization (>1 week) include Proteus mirabilis, E coli, P aeruginosa, Providencia stuartii, Morganella morganii, Citrobacter sp, Enterobacter sp, Enterococcus sp and Candida spp.

In patients with DM, common causative organisms include E coli, Klebsiella pneumoniae, P mirabilis, P aeruginosa, Enterobacter sp, Enterococcus sp and Candida spp. In renal transplant patients, causative organisms include E coli, P mirabilis, K pneumoniae, P aeruginosa, Gram-positive cocci, Enterobacter sp, Enterococci sp, Serratia sp, Acinetobacter sp, Citrobacter spp and Corynebacterium urealyticum. In neutropenic patients, causative organisms include Gram-negative bacilli, especially P aeruginosa, Staphylococcus aureus and Candida sp, whereas in patients with anatomic abnormalities, common organisms include E coli, K pneumoniae, P aeruginosa and P mirabilis.

Yếu tố nguy cơ

Factors associated with complicated UTI include:

• More than 7 days of symptoms prior to presentation
• Azotemia due to intrinsic renal disease
• Vesicoureteral reflux or other functional abnormalities
• Obstructive uropathy (eg bladder outlet obstruction, calculi, stones, stricture, tumor)
• Incomplete voiding with >100 mL of residual urine
• Renal insufficiency and transplantation
• Chemical or radiation injuries of the uroepithelium
• Comorbidities that predispose to papillary necrosis (eg sickle cell disease, severe DM, analgesic abuse, Pseudomonas sp infection)
• Immunosuppression
• Male sex
• Pregnancy
• Elderly
• Healthcare-associated infection
• Residence in an institution providing extended care
• Foreign body
• Presence of an indwelling urinary catheter or use of intermittent bladder catheterization
• Recent urinary tract instrumentation, intervention and/or modification (eg ileal loop or pouch)
• Peri- and postoperative UTI
• Recent antimicrobial use
• Unresolved UTI due to failed response to antibiotic therapy
• Isolated extended spectrum beta-lactamase (ESBL)-producing and multidrug-resistant organisms
• Exposure or travel to areas where multidrug-resistant organisms are prevalent