UTI Ebadur Rahman FRCP (Edin),FASN, Specialty Certificate in Nephrology (UK) MRCP (UK), DIM (UK), DNeph (UK), MmedSciNephrology (UK). Consultant & clinical tutor Department of Nephrology Riyadh Armed Forces Hospital

Urinary Tract Infection (UTI) Background 1.Bacterial infections of urinary tract are a very common reason to seek health services 2.Common in young females(50%) and uncommon in males under age 50 3.Common causative organisms a.Escherichia coli (gram-negative enteral bacteria) causes most community acquired infections b.Staphylococcus saprophyticus, gram-positive organism causes 10 – 15% c.Catheter-associated UTI’s caused by gram-negative bacteria: Proteus, Klebsiella, Seratia, Pseudomonas

Natural protection Normal mechanisms that maintain sterility of urine Adequate urine volume Free-flow from kidneys through urinary meatus Complete bladder emptying Normal acidity of urine Peristaltic activity of ureters and competent ureterovesical junction Increased intravesicular pressure preventing reflux In males, antibacterial effect of zinc in prostatic fluid IGA in urogenital tract

Pathophysiology 1.Pathogens which have colonized urethra, vagina, or perineal area enter urinary tract by ascending mucous membranes of perineal area into lower urinary tract 2.Bacteria can ascend from bladder to infect the kidneys 3.HEMATOGENOS ROUTE

Reinfection is a new episode of bacteriuria with a microorganism that is different from the original one (eg, bacteriuria with Klebsiella species when the original infection was caused by E coli). Recurrence is infection that usually occurs within 2 weeks of stopping antibiotic therapy with same organism.

To obtain a clean-catch, midstream specimen, – the urethral opening is washed with a mild, nonfoaming disinfectant and air dried. – Contact of the urinary stream with the mucosa should be minimized by spreading the labia in women – and by pulling back the foreskin in uncircumcised men. – The first 5 mL of urine is not captured; the next 5 to 10 mL is collected in a sterile container. A specimen obtained by catheterization is preferable in older women culture, should be done within 2 h of specimen collection; if not, the sample should be refrigerated.

Microscopic examination Pyuria is defined as ≥ 8 WBCs/μL of uncentrifuged urine, which corresponds to 2 to 5 WBCs/high-power field in spun sediment. Most truly infected patients have > 10 WBCs/μL. The presence of bacteria in the absence of pyuria, especially when several strains are found, is usually due to contamination during sampling. Microscopic hematuria occurs in up to 50% of patients, but gross hematuria is uncommon. WBC casts, can be present in pyelonephritis, and noninfective tubulointerstitial nephritis

Sterile pyuria Pyuria in the absence of bacteriuria – if patients have nephrolithiasis, – a uroepithelial tumor, – TB – Women who have dysuria and pyuria but without significant bacteriuria have the urethral syndrome or dysuria-pyuria syndrome

Dipstick tests A positive nitrite test on a freshly voided specimen is highly specific for UTI, but the test is not very sensitive. The leukocyte esterase test is very specific for the presence of > 10 WBCs/μL and is fairly sensitive.

For outpatient treatment of uncomplicated pyelonephritis ciprofloxacin (500 mg orally twice daily for seven days or 1000 mg extended release once daily for seven days) ciprofloxacin – or levofloxacin (750 mg orally once daily for five to seven days)levofloxacin – The bioavailability and urinary penetration of fluoroquinolones with oral dosing is comparable to intravenous dosing. – In women who have severe pyelonephritis, and resistance suspected -IV therapy ceftriaxone (1 gram) or an aminoglycoside (consolidated 24 hour dose).ceftriaxone

LOWER UTI ●Nitrofurantoin (100 mg orally twice daily for 5 days);Nitrofurantoin 90 to 95 percent cure rate Nitrofurantoin should be avoided if there is suspicion for early pyelonephritis, and is contraindicated when creatinine clearance is <60 mL/minute. ●Trimethoprim-sulfamethoxazoleTrimethoprim-sulfamethoxazole – twice daily for 3 days – clinical efficacy rate 90 to 100 percent

Medication duration Short-course therapy: 3 day course of antibiotics for uncomplicated lower urinary tract infection; (single dose associated with recurrent infection) 7 – 10 days course of treatment: for pyelonephritis, urinary tract abnormalities or stones, or history of previous infection with antibiotic-resistant infections

Surgery Surgical removal calculus from renal pelvis cystoscopic removal of bladder calculi extracorporeal shock wave lithotripsy (ESWL) Ureteroplasty: surgical repair of ureter for stricture or structural abnormality; reimplantation if vesicoureteral reflux