UTI Flashcards
What are common causative organisms of UTIs?
E. coli – most common
Staph. saprophyticus
**95% from GI tract
In infants, (M, F) more commonly have UTI’s.
In 3-50 y/o, (M, F) more commonly have UTI’s.
M
F
What age group has the highest rate of bacteriuria?
> 65
What are contributing factors that increase # UTI’s in younger ages?
sex
pregnancy
What contraceptives have increased incidence of UTI?
diaphragm/spermicide > spermicidal foam/condoms > oral contraceptives
What is the most common route of infection?
95%: Ascending route (Urethral trauma, Intercourse, Instrumentation, Diaphragm use)
<5%: Hematogenous route
Mechanisms for pathogenesis of UTIs?
Adhesion
Colonization
Invasion
Phase variation
What bacterial factors contribute to UTI’s?
- Uropathogenic E. coli = Virulence factors
2. Structural = adhesions on fimbriae (type 1 and p-)
**ADD INFO ON PATHOGEN!
**
Host Defense Mechanisms?
Bacterial growth inhibition
Urine flow
Epithelial cell turnover
Antibodies
Predisposing host factors?
Urine flow obstruction Female factors Abnormal urine flow Urethral trauma Vesiculo-ureteral reflux Instrumentation
Clinical Manifestations of UTI of lower tract?
Frequency of urination Dysuria - painful urination Turbid urine Suprapubic discomfort Hematuria Asymptomatic cystitis
Clinical Manifestations of UTI of upper tract?
Fever
Chills
Flank pain and “CVAT”
Asymptomatic pyelonephritis
Dx of UTI?
Microscopic urinalysis Gram stain of urine Urine culture Blood cultures (PRN) Screening tests
Complications of UTI:
Gram negative sepsis Intrarenal or extrarenal abscess Chronic renal insufficiency Struvite renal calculi Recurrent infection
Prevention of UTI:
Proper use of urinary catheterization
Correction of anatomic abnormalities
Prophylactic antibiotics - RARELY
Abx treatment for asymptomatic bacteriuria in elderly?
none!
Abx treatment of upper tract UTI?
1-6 weeks (IV vs oral therapy)
Abx treatment of upper tract UTIs for M vs F?
Males: 1 week
Females: 1-3 days (but longer if complicated UTI)
pus in urine (inflammation or infxn)
Pyuria
inflamm. of renal pelvis (upper UTI)
Pyelonephritis
symptoms of UTI (frequency, urgency, dysuria), but no apparent source of infxn

Acute urethral syndrome
How do birth control methods increase UTI risk?
spermicide changes flora of vagina
diaphragm changes angle of urethra, may ↑ reflux
Abx which are best at concentrating more in inflamed kidney than uninflamed
Aminoglycosides (tobramycin, gentamicin)
Abx which concentrate about the same in inflamed vs uninflamed
Sulfonamides and trimethoprim
Abx which concentrate LESS in inflamed kidney than uninflamed
Ampicillin/cephalothin
Abx which can treat prostatitis
Cipro
impairs phagocytosis
Capsular polysaccharide [K antigen]
Proteins at the end of type 1 fimbrae can bind:
Why is this important?
mannose in host tissues (=attachment)
Mannose present in lower UT → lower UTI
P antigen present in:
Why is this important?
in renal pelvis
expression of P-fimbriae → pyelonephritis
