Notes on Recurrent Urinary Tract Infections

Urinary tract infection (UTI) is a common bacterial infection in women, affecting 20% of women aged 20–56 annually.
Approximately one in four women will experience a recurrence of UTI.
The average rate of acute cystitis is 0.5–0.7 episodes/year per individual, with 40–50% of women suffering from at least one UTI in their lifetime.
Recurrence Rates: 27% within 6–12 months, higher in catheterized individuals (< 60 days).

Bacteriuria: Presence of bacteria in urine.
- Symptomatic: 100 CFU/mL is diagnostic.
- Asymptomatic: Requires 100,000 CFU/mL.
RUTI: Defined as three or more symptomatic UTIs within a 12-month period.
- Re-infection vs Relapse:
- Re-infection: New infection or same organism regrown >2 weeks post-treatment.
- Relapse: Same bacterial strain from urinary tract within 2 weeks of treatment.
RUTIs due to re-infection are more prevalent (80% of cases).

Sexual Intercourse: Strongly associated with RUTIs. Introduces uropathogens into the bladder mechanically (Foxman et al).
Contraceptive Use: Particularly with spermicides and diaphragms, altering vaginal flora in favor of uropathogens, increasing UTI risk (Fihn et al).
Antimicrobial Use: Disruption of normal flora can lead to reduced resistance to uropathogens, promoting persistent colonization by E. coli (Hooton et al).
Oestrogen Levels: Role is controversial; deficiency increases UTI risk in postmenopausal women, but excess estrogen can increase adherence of uropathogens (Hooton et al).
Genetics: Familial predisposition noted in cases of RUTI with increased incidence in non-secretors of ABO histo-blood group antigens.
Distance of Urethra from Anus: Shorter distances potentially increase risk, albeit this is modest (Hooton et al).

Divided into healthy vs. elderly institutionalized women, the latter being at higher risk.
Factors include oestrogen deficiency, previous UTIs, urogenital surgery, and incontinence (Raz and Stamm).

Often involve multi-resistant pathogens; risk factors include urinary stasis conditions such as kidney stones or neurogenic bladder.

Pathogens: Primarily E. coli (70–95% of cases), followed by Staphylococcus saprophyticus (5–20%), and less common pathogens like Proteus mirabilis and Klebsiella species.
Common strains recur due to re-infection from gut flora (Russo et al).

UTIs often begin with colonization of the vagina by enteric bacteria, such as E. coli.
Uropathogenic E. coli (UPEC) utilizes adhesins to attach to bladder epithelial cells and form biofilms which protect them from host defenses and antibiotics.
The repeated cycle of colonization, infection, and recurrence is central to RUTI development.

Classic symptoms: Dysuria, frequency, urgency, and suprapubic discomfort. Upper tract infection may present with loin pain, haematuria, and fever.
Elderly patients may show generalized malaise or confusion.

Urine Examination: Clean-catch sample; microscopy and culture are the gold standard for diagnosis.
Urinalysis: Dipstick tests may show nitrates/nitrites but have high false-negative rates.
Blood Tests: Useful if pyelonephritis or diabetes suspected.
Imaging: Ultrasound for upper tract infections, and cystourethroscopy for complications.

Risk Factor Correction: Address contraception methods and manage incontinence in the elderly.
Antibiotic Therapy: Full course therapy followed by prophylactic strategies:
- Long-term Prophylaxis: Administer low-dose antibiotics for 6–12 months.
- Post-coital Prophylaxis: Immediate antibiotic dose after sexual intercourse.
- Patient-initiated Therapy: Patients can start antibiotics at the first sign of symptoms.
Oestrogen Therapy: For postmenopausal women, may help restore normal flora (controversial).
Cranberry Juice: May reduce recurrent bacteriuria through various mechanisms, available anecdotal evidence supports its use.

Focus on optimal durations of prophylaxis, genetics of susceptibility, and potential vaccine development for RUTI prevention.

RUTIs significantly affect women's health, necessitating a multifaceted approach for management including risk factor evaluation, proper diagnostics, and effective prevention strategies.