Lec 28 UTIs Flashcards
What are 4 mechs of UTI infection?
ascending from urethra = most common
hematogenous: from bacteremia
lymphatic [rare]
direct extension from IBD/PID
What is the most common UTI pathogen?
E Coli = 85% of community acquired; 50% of nosocomial
What are risk factors for UTI?
past history, sexual intercourse, diabetes, lack of circumcision, AIDS
What virulence factors are involved in E Coli UTI?
bacterial fimbrae/pili allow higher degree of adherence
What are some host protective factors from UTI?
- efficient emptying of bladder w/ void to decrease colony count
- glycosaminoglycan layer = interferes with bacterial adherence
What makes women particularly suscpetible to UTIs?
- have short urethra = facilitates ascent into bladder
- those with recurrent UTI may have more adhesion receptors for pathogen binding
- women whose mucosal secretions lack fucosyl transferase may be prone
What are male-specific factors that increase risk of UTI?
- uncircumcised = higher incidence of UTI
- lower zinc secretion from prostate [usually acts as an antibacterial]
What is an uncomplicated UTI?
infection in patient with structurally and functionally normal urinary tract [includes isolated or recurrent bacterial cystitis and acute pyelonephritis]
eradicated with short course of oral antibiotics
What is a complicated UTI?
infection with structural or functional impairment that reduces efficacy of antibiotics; seen commonly in older men with prostate problems
What is treatment of complicated UTI?
prolonged course of antibiotics; may need urologic evaluation and treatment
What is asymptomatic bacteriuria?
absence of symptoms and no pyuria on UA BUT urine culture demonstrates bacterial growth
How do you treat asymptomatic bacteriuria?
no treatment needed unless obstruction, pregnant, or diabetic
What is cystitis? presentation?
lower UTI –> dysuria, frequency, urgency, suprapubic pain/fullness
What are major pathogens that cause cystitis?
E coli 70-80%
Enterobacter 20%
S. saprophyticus 10-20%
What is treatment for cystitis?
3 day course or single dose of antibiotics
What is presentation of acute pyelonephritis?
infection of renal parenchyma = dysuria and increased frequency, fever, chills, flank pain
What is treatment of acute pyelonephritis?
usually treat with IV antibiotics at least until symptoms improve
What is treatment of a perinephric abscess?
can be a complication of pyelonephritis –> requires percutaneous or open drainage and empiric antibiotics
mortality up to 50%; may need nephrectomy
What is infected in acute vs chronic pyelonephritis?
acute = infection of renal parenchyma chronic = diffuse interstitial inflammation of kidney
What is infected in cystitis?
superficial mucosal infection of bladder
What is infected in urethritis?
inflammation of urethra usually due to sexually transmitted infection
What is definition of pyuria
10 or greater leukocytes / high power field; leukocyte esterase test on dip stick urine = rapid screen
What is standard technique for urinalysis?
clean catch mid stream urine
What is the threshold for significant urine culture? what about if symptomatic man/woman?
standard = 100,000 or more organisms/ml of urine
symptomatic women: 100 cfu/ml
symptomatic men: 1000 cfu/ml
