UTIs

Question 1

Characteristics of Complicated UTIs

Answer 1

• associated w/ catheters, metabolic disorders, kidney stones
• symtoms are often non-specific
• infection can be life-threatening

Question 2

Characteristics of Uncomplicated UTIs

Answer 2

F>M, increased risk with sexual intercourse, use of diaphragm and spermicides, etc.

Question 3

Symptoms of

1. Cystitis
2. Acute Pyelonephritis

Answer 3

1. dysuria, urinary freq/urgency, suprapubic pain
2. • fever, flank pain, WBC casts, leukocytosis, elevated CRP, bacteremia (30% of cases)

Question 4

Two causes of

1. Cystitis
2. Pyelonephritis

Answer 4

1. introduction of normal bowel/vaginal flora -OR- catheter related
2. ascension of infection -OR- hematogenous spread

Question 5

E coli (80%)

*UPEC = uropathogenic E. coli

Answer 5

1 most common cause, UNCOMPLICATED UTIs

Gm – bacilli, fast lactose fermenter, indole +

(1) Type I Fimbriae -> colonization of bladder, exfoliation
(2) P Pili -> colonization of kidney, digalactoside receptors
(3) Hemolysin -> damages cell membranes
(4) Cytonecrotizing Factor (CNF) toxin -> damages cytoskeleton, inhibits rho GTPases

Question 6

Proteus mirabilis

Answer 6

most common cause of COMPLICATED UTIs

high association with struvite/AMP kidney stones

Gm – bacilli, lactose non-fermenter, oxidase –, urease +

*alkaline urine w/ ammonia scent

(1) formation of biofilms
(2) swarming motility on agar
(3) predilection for upper urinary tract
(4) urease -> precipitation of salts, stones

Question 7

Staphyloccus saprophyticus

Answer 7

2nd most common cause in sexually active young women

Gm + coccI, clusters

catalase + (Staph)

coagulase – (not aureus)

novobiocin resistant

Question 8

Staphyloccus epidermidis

Answer 8

common infection due to indwelling medical devices

Gm + coccI, clusters

catalase + (Staph)

coagulase – (not aureus)

novobiocin sensitive

Question 9

Pseudomonas aeruginosa

Answer 9

common cause of complicated UTIs, especially catheter and kindey stone related

Gm – bacilli, lactose/glucose non-fermenter, oxidase +

blue/green colonies w/ artificial grape scent

Question 10

Enterococcus faecalis

Answer 10

Gm + coccI

grows in 40% bile, 6.5% NaCl

Question 11

Which organisms are the most common causes of acute pyelonephritis?

Answer 11

infection of the kidney due to

(1) ascending infection - E. coli (90%)
(2) hematogenous spread - Staphylococcus

associated w/ kidney stones? Proteus (and others) but NEVER E. Coli

Question 12

Chronic Pyelonephritis is associated with ______ and looks like ______.

Answer 12

1. VU reflux
2. stones/obstruction/stasis
   - > cortical scarring w/ **blunted calyces, thyroidization of tubules. **