Week 6: UTI ID Flashcards Preview

CRRAB 1 > Week 6: UTI ID > Flashcards

Flashcards in Week 6: UTI ID Deck (52):
1

What type of bacteria cause most UTIs? What % of the time is it this type?

Normal enteric flora, 95%. Note: these are not the species that cause GI disease.

2

What is ABU?

Asymptomatic bacteriuria. UTI minus symptoms.

3

First line antimicrobials for uncomplicated UTI for men vs women

Men: Fluoroquinolone or TMP-SMX
Women: Nitrofurantoin or TMP-SMX

4

Therapy for complicated UTIs

Individualized, based on culture results

5

Natural barriers to harmful pathogens in urinary tract (4)

acidity of urine, act of urination -> desquamation, mucosal lining, urethral sphincter

6

What percent of UTIs occur by bacteria ascending the urethra? How do the rest occur?

90%. Rest are hematogenous.

7

What makes a UTI complicated?

underlying factors -> predisposed to ascending bacterial infection e.g. catheter, anatomic abnl, obstruction of urine flow, poor bladder emptying.

8

How do antibiotic and spermicide use make UTI more likely?

Change vaginal flora allowing for overgrowth of E. coli.

9

Pathogen most common for acute uncomplicated UTI. What percent of the time? How does it accomplish this?

E. coli 75%. Special attachment factors for transitional epithelium

10

____ is the #2 cause of uncomplicated UTI and accounts for ___%, more frequent in ________.

Staphylococcus saprophyticus, 5-15%, younger women

11

5-10% of uncomplicated UTIs caused by what other enteric organisms?

Klebsiella, Proteus, Enterococcus, Citrobacter.

12

Most common cause of complicated UTI

E. coli

13

Other causes of complicated UTI

Aerobic and facultative anaerobic gram neg rods inc: Klebsiella, Proteus, Citrobacter, Acinetobacter, Morganella, and Pseudomonas. Gram Pos: enterococci and staph aureus. Yeasts. (prob don't need to know all these, just that there are many).

14

E. coli virulence factors contributing to UTI

Surviving low pH + surface adhesions. P fimbriae: hair-like protein interacting w renal epithelial cells, important in pyelonephritis and subsequent bloodstream invasion. Type 1 pilus (fimbria): all e. coli possess, not all express, mediate binding to uroplakins on bladder uroepithelial cells.

15

How does Sulfamethoxazole work?

Inhibits PABA to DHF via dihydropteroate synthetase

16

How does Trimethoprim work?

Inhibits conversion of DHF to THF via dihydrofolate reductase

17

How do the fluoroquinolones work?

Bind topo II/DNA gyrase --> tension -> double strand breaks

18

How does nitrofurantoin work?

Bacterial nitrofuran reductase reduces the drug -> damage or inactivate ribosomal proteins

19

How does urine chemistry block colonization? (3)

Acidity, lysozyme (breaks down peptidoglycan), lactoferrin (binds iron to prevent microorganisms from scavenging it)

20

How do the epithelial cells of the urinary tract prevent colonization?

Surface proteins differ from those of GI tract - prevents most enteric from gaining a foothold

21

What adaptive immune response defends the urinary tract?

Secretory IgA (requires previous exposure)

22

How does normal flora of the urinary tract prevent pathological colonization?

Physical barrier

23

What are the 3 major threats to the urinary system?

Microorganisms moving from GI to urinary tract, catheters, immune system malfunction -> glomerulonephritis

24

Cause of urine cloudiness in UTI (2)

Bacteria and WBCs

25

Back pain with UTI symptoms suggests

Progression of infection to kidneys

26

Cause of orange-tinged urine

Pyridium or blood

27

Overall incidence of UTI in young women

0.5-0.7 episodes/year, recurring in 25-30%

28

Most common cause of nosocomial UTI

Catheter related (40%)

29

UTI in children suggests

Anatomic or functional abnormality

30

Slide 12

a

31

Slide 12

a

32

How many times more likely are UTIs in women than men

10-50x

33

What does drinking cranberry juice help?

Blocks bacterial attachment to the epithelium

34

Lab findings for uncomplicated UTI (2)

Pyuria: 10+ neutrophils/ high power field
Bacteriuria >10^5 CFU/ mL urine

35

How may colony counts differ in complicated UTIs?

Can be much lower

36

Slide 17

a

37

What is selective media?

Contains compounds that selectively inhibit growth of some microbes but not others

38

What is differential media?

a

39

What is defined medium

a

40

What is undefined medium?

a

41

2 common microorganism culture tests

Catalase test, cytochrome oxidase test

42

How does the catalase test work?

Put a couple drops of hydrogen peroxide on bacteria. Bubbles = catalase pos, nothing = neg

43

Staph, enterococcus, and strep catalase and oxidase statuses

Staph: catalase pos
Strep: catalase neg
Entero: catalase neg

44

What test can differentiate staph aureus from saprophyticus?

Coagulase: pos with aureus, neg with other staph (saprophyticus and epidermidis

45

How does the coagulase test work?

Bacteria + fibrinogen = clumping? Pos: solid gelatin mass in test tube, neg test stays liquid.

46

What test can differentiate between epidermidis and saprophyticus?

Novobiocin sensitivity test

47

Novobiocin sensitivity/ resistance of epidermidis and saprophyticus

Epidermidis: sensitive. Saprophyticus: resistant

48

What does novobiocin do?

Inhibits DNA gyrase in susceptible micoorganisms

49

After taking antibiotics for a UTI, women are particularly susceptible to ____

Yeast, esp candida. This is an endogenous overgrowth.

50

What microscopic finding is suggestive of yeast?

Hyphae

51

Gram positive gamma hemolytic microorganism

Saprophyticus or enterococcus (sapro statistically more likely)

52

Start at slide 28

f