Urinary tract infections (UTIs) can be asymptomatic or symptomatic, affecting the bladder (cystitis) or kidneys (pyelonephritis). Escherichia coli is the most common cause of uncomplicated UTIs, while complicated UTIs involve other gram-negative rods or yeasts. Diagnosis involves urinalysis, urine culture, and symptom assessment. Treatment consists of short courses of antibiotics like nitrofurantoin, trimethoprim-sulfamethoxazole, or fluoroquinolones. Recurrent UTIs may be prevented with continuous or postcoital antibiotic prophylaxis.

1. Urinary Tract Infections
Dr. Kamau David

2. Introduction
• UTI may be asymptomatic (subclinical
infection) or symptomatic (disease).
• Urinary tract infection encompasses a variety
of clinical entities, including asymptomatic
bacteriuria (ASB), cystitis, prostatitis, and
pyelonephritis.

3. Introduction……..
• ASB occurs in the absence of symptoms attributable to the
bacteria in the urinary tract and usually does not require
treatment
• Cystitis, symptomatic infection of the bladder;
• Pyelonephritis, symptomatic infection of the kidneys.
• Uncomplicated urinary tract infection refers to acute
cystitis or pyelonephritis in nonpregnant outpatient women
without anatomic abnormalities or instrumentation of the
urinary tract;
• Complicated urinary tract infection encompasses all other
types of UTI.
• Recurrent urinary tract infection is not necessarily
complicated; individual episodes can be uncomplicated and
treated as such.
• Catheter-associated bacteriuria can be either symptomatic
(CAUTI) or asymptomatic.

4. Epidemiology
• UTI occurs far more commonly in females than in males
except in Elderly and infants.
• In infancy - UTI is slightly higher among males than among
females because male infants more commonly have
congenital urinary tract anomalies.
• After 50 years of age, obstruction from prostatic hypertrophy
becomes common in men, and the incidence of UTI is almost
as high among men as among women.
• Between 1 year and ~50 years of age, UTI and recurrent UTI
are predominantly diseases of females.
• The prevalence of ASB is ~5% among women between ages
20 and 40 and may be as high as 40–50% among elderly
women and men.
• As many as 50–80% of women in the general population
acquire at least one UTI during their lifetime—uncomplicated
cystitis in most cases

5. Risk Factors
• Female gender
• Frequent Sexual intercourse – use of Spermicides
• Congenital abnormalities – PUVs
• Instrumentations – catheterization
• Diabetes – Increased use of insulin and Duration of DM, Use
of SGLT-2 inhibitors
• Poor bladder function,
• Obstruction in urinary flow – BPH, Urolithiasis
• Incomplete voiding
• Incompetence of the vesicoureteral orifice, resulting in
vesicoureteral reflux (VUR), is an important cause of
ascending infection. VUR is present in 20% to 40% of young
children with UTI
• Major risk factors for recurrent UTI include a history of
premenopausal UTI and anatomic factors affecting bladder
emptying, such as cystoceles, urinary incontinence, and
residual urine

6. Etiology
Uncomplicated UTI
• E. coli accounts for 75–90% of isolates;
• Staphylococcus saprophyticus for 5–15% (with particularly
frequent isolation from younger women);
• Klebsiella, Proteus, Enterococcus, and Citrobacter species,
along with other organisms, for 5–10%.
In complicated UTI (e.g., CAUTI),
• E. coli remains the predominant organism, but other aerobic
gram-negative rods, such as Pseudomonas aeruginosa and
Klebsiella, Proteus, Citrobacter, Acinetobacter, and
Morganella species, also are frequently isolated.
• Gram-positive bacteria (e.g., enterococci and Staphylococcus
aureus) and yeasts also are important pathogens in
complicated UTI

7. Pathogenesis
• Ascending infection from the lower urinary
tract is the most important and frequent route
by which bacteria reach the kidney.
• Haematogenous spread is rare – seeding of
bacteria in Infective endocarditis
• The relationship among specific host, pathogen,
and environmental factors determines the
clinical outcome.

8. Pathways of
renal Infection

9. Pathogenesis of urinary tract infection.

10. Diagnosis
• The clinical history itself has a high predictive
value in diagnosing uncomplicated cystitis; the
likelihood of UTI is 96% in a pt presenting with
both dysuria and urinary frequency in the
absence of vaginal discharge.
• A urine dipstick test positive for nitrite or
leukocyte esterase can confirm the diagnosis
• The detection of bacteria in a urine culture is the
diagnostic gold standard for UTI.
• A colony-count threshold of ≥102 bacteria/mL is
more sensitive (95%) and specific (85%) than a
threshold of 105/mL for the diagnosis of acute
cystitis in women with symptoms of cystitis.
• ASB requires ≥105 bacteria/mL in the absence of
clinical symptoms referable to cystitis.

11. Diagnostic approach to urinary tract infection (UTI). ASB, asymptomatic bacteriuria; CA-ASB, catheter-
associated ASB; CAUTI, catheter-associated UTI; STD, sexually transmitted disease.

12. Treatment
• Nitrofurantoin remains highly active against E. coli and
most non–E. coli isolates. – Nitrofuranton 100mg BD
for 5-7 days
• Proteus, Pseudomonas, Serratia, Enterobacter, and
yeasts are all intrinsically resistant to this drug.
• 3-day course of TMP-SMX for treatment of acute
cystitis;
• Most fluoroquinolones are highly effective as short-
course therapy for cystitis; the exception is
moxifloxacin,
• The fluoroquinolones commonly used for UTI include
ciprofloxacin and levofloxacin

14. Pyelonephritis
– 7-day course of therapy with oral ciprofloxacin (500 mg twice
daily, with or without an initial IV 400-mg dose)
– Oral TMP-SMX (DS twice daily for 14 days) also is effective for
treatment of acute uncomplicated pyelonephritis
– Parenteral therapy for uncomplicated pyelonephritis include
fluoroquinolones, an extended-spectrum cephalosporin with or
without an aminoglycoside, or a carbapenem
• Combinations of a β-lactam and a β-lactamase inhibitor
(e.g., ampicillin-sulbactam, ticarcillin-clavulanate,
piperacillin-tazobactam) or a carbapenem (imipenem-
cilastatin, ertapenem, meropenem) can be used in patients
with more complicated histories, previous episodes of
pyelonephritis, anticipated antimicrobial resistance, or
recent urinary tract manipulations
UTI IN PREGNANT WOMEN
• Nitrofurantoin, ampicillin, and the cephalosporins are safe
• Candiduria - Fluconazole (200–400 mg/d for 7–14 days

15. PREVENTION OF RECURRENT UTI
• Women experiencing symptomatic UTIs ≥2
times a year are candidates for prophylaxis—
either continuous or postcoital or pt-initiated
therapy.
• Continuous prophylaxis and postcoital
prophylaxis usually entail low doses of TMP-
SMX, a fluoroquinolone, or nitrofurantoin

16. Thank You