URINARY TRACT INFECTIONFarieda Ariyanti

Definition• Significant bacteriuria : presence of 100,000 or more

colonyforming units (CFU) of bacteria per milliliter of urine

• Anatomic location: upper (kidney) and lower (bladder, prostate, and urethra) UTIs.

• An uncomplicated and complicated infection ▫ Uncomplicated infection is an episode of cystourethritis

following bacterial colonization of the urethral and bladder mucosae in the absence of upper tract disease.

▫ Complicated UTI is UTI that increases risk for serious complication and treatment failuremay occur with pregnancy, diabetes, immunosupression, structural abnormalities of the urinary tract, symptoms lasting for more than 2 weeks, and previous pyelonephritis.

Definition

•Recurrence of UTI is the result of either relapse or reinfection. ▫Reinfection is a recurring infection due to a

different microorganism, which is usually drug susceptible.

▫Relapse is a return of infection due to the same microorganism, which often is drug resistant.

definition

•Asymptomatic bacteriuria is defined as two separate consecutive clean-voided urine specimens both with 105 or more colonyformingunits (cfu)/ml of the same uropathogen in the absence of symptoms referable to the urinary tract.

•asymptomatic bacteriuria is an important clue to the presence of parenchymal infection somewhere in the urinary tract

RISK FACTORS

Pathogenesis

•Bacteria in the enteric flora periodically gain access to the genitourinary tract.

•How such bacteria actually migrate from the gastrointestinal tract to the periurethra is not knownclose proximity of the anus in women is a likely factor.

•The subsequent bacterial colonization of uroepithelial cells is the biological phenomenon that sets the stage for persistent

Pathogenesis• After periurethral colonizationuropathogens

gain access to the bladder through the urethra, to the kidneys through the ureters, and to the prostate through the ejaculatory ducts.

• The urethra and ureterovesical junction are mechanical barriers that prevent ascension.

• factors promoting ascent of bacteria are not as well understood (Besides instrumentation and mechanical obstruction)

• In the bladder, organisms multiply, colonize the bladder mucosa, and invade the mucosal surface.

Pathogenesis

•Bladder bacteriuria sets the stage for subsequent migration to the kidneys, where organisms such as P-fimbriated E. coli adhere to renal tubular cells this E. coli strain is the most common cause of pyelonephritis.

•Other host factors that prevent a renal infection are a high urine osmolality, high ammonium concentration, phagocytes, and increased urine flow rate.

Pathogenesis

•the bladder has several mechanisms that prevent bacteriuria:▫ (a) a mucopolysaccharide (urine slime)

layer covers the bladder epithelium and prevents colonization;

▫(b) Tamm-Horsfall protein, which is a component of uromucoid, adheres to P fimbriae and prevents colonization; and

▫ (c) urine flow and bladder contraction serve to prevent stasis and colonization.

pathogenesis• presence of a urethral catheter defense

mechanisms impaired both by disruption of the protective glycosaminoglycan layer of the bladder and the formation of biofilm on the catheter.

• Microorganisms in the biofilm are protected from antibiotics, host defenses, and mechanical flushingEffective therapy ultimately requires removal of the catheter.

• The incidence of bladder cancer may be increased with prolonged catheter use that exceeds 10 years as in patients with spinal cord injuries.

Gejala klinis

urinalysis• pyuria is a highly sensitive indicator in symptomatic

patientsdemonstrated in nearly all acute bacterial UTIs, and its absence calls the diagnosis into question.

• The leukocyte esterase "dipstick" method is less sensitive than microscopy in identifying pyuria but is a useful alternative when microscopy is not feasible.

• sterile pyuria may indicate infection with unusual agents such as C. trachomatis, U. urealyticum, or Mycobacterium tuberculosis or with fungi.

• sterile pyuria may be documented in noninfectious urologic conditions calculi, anatomic abnormality, nephrocalcinosis, vesicoureteral reflux, interstitial nephritis, or polycystic disease.

URIN CULTURE• symptomatic patients: bacteria 105/mL• asymptomatic patients:

▫ two consecutive urine specimens should be examined bacteriologically before therapy is instituted, and

▫ 105 bacteria of a single species per milliliter should be demonstrable in both specimens.

• due to bacterial multiplication in the bladder cavity, samples of urine from the ureters or renal pelvis may contain <105 bacteria per milliliter

• bacteriuria of any degree in suprapubic aspirates or of 102 bacteria per milliliter of urine obtained by catheterization usually indicates infection.

• antibiotic treatment, high urea concentration, high osmolarity, low pH urine inhibits bacterial multiplication, resulting in relatively low bacterial colony counts despite infection.

Indications for and choice of renal imaging

•Acute infection▫Severe pain , infection does not settle on

treatment should have ultrasonography and plain radiographs to exclude pyonephrosis, intrarenal or perinephric sepsis or calculi.

▫Renal or perinephric abnormalities seen on ultrasonography may require elucidation by CT

▫may also be indicated if ureteric colic is suspected when IVU or spiral unenhanced CT should be used

• In women,▫ no indication for imaging following a single or infrequent

infection. ▫ Recurrent attacks more often than 2 per 6 months should be

investigated by ultrasonography and plain radiographs.• In men

▫ urinary infection is so much less common than in women that imaging is indicated after the first documentation of bacteriuria to exclude predisposing factors, especially impaired bladder emptying.

▫ Ultrasonography and plain radiographs are the best first choice • considered if

▫ urinary infection slow to resolve, relapseâ, pyuria, risk factors for papillary necrosis.

Imaging after treatment of infection

Management

Lower UTI

•Principal: adequate hydration and antibiotic, urine alkalinization as needed

•80% patient respond well after 48 hours treatment with single antibiotic

•Persistent symptom and leucosuria tx 5-10 days

•Urinalysis and culture aren’t needed if symptom and leucosuria cleared

Prognosis•uncomplicated cystitis or pyelonephritis

ordinarily results in complete resolution of symptoms.

•Cystitis may also result in upper tract infection or in bacteremia (especially during instrumentation), but little evidence suggests that renal impairment follows

•Acute uncomplicated pyelonephritis in adults rarely progresses to renal functional impairment and chronic renal disease

prognosis• Repeated upper tract infections often represent relapse

rather than reinfection, and renal calculi or an underlying urologic abnormality should be vigorously soughtIf neither is found, 6 weeks of chemotherapy may be useful in eradicating an unresolved focus of infection.

• Repeated symptomatic UTI in obstructive uropathy, neurogenic bladder, structural renal disease, or diabetes can progress to renal scarring and chronic renal disease

• Asymptomatic bacteriuria in these groups as well as in adults without urologic disease or obstruction predisposes to increased numbers of episodes of symptomatic infection but does not result in renal impairment

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