UTI Micro- Debiel Flashcards Preview

CRRAB II- FINAL > UTI Micro- Debiel > Flashcards

Flashcards in UTI Micro- Debiel Deck (43):
1

Why are B-lactam antibiotics not recommended as first line therapy for acute uncomplicated cystitis?

Widespread E. coli resistance rates above 20 percent!

2

What is the key feature distinguishing cystitis and pyelonephritis?

Pyelonephritis will have a fever

3

Only members of what bacterial family convert nitrate to nitrite?

Enterobacteriaceae (E. Coli)

4

What is the gold standard for diagnosing UTI?

Detection of bacteria in urine culture

5

First line treatments for uncomplicated cystitis?

Nitrofurantoin
Bactrim (Trimethoprim/sulfamehtoxazole)

6

First line treatment for acute uncomplicated pyelonephritis?

Fluoroquinolones (ciprofloxacin, levofloxacin)

OR

Bactrim or Ceftriaxone

7

What is the central pathogenesis for catheter associated UTIs?

Formation of BIOFILM (a living layer of uropathogens) on the urinary catheter

8

What are three phrophylactic strategies for UTI management?

Continuous Antibiotics
Postcoital antibiotics
Patient- initiated therapy

9

What are the 4 general defenses of the urinary tract?

1. Mechanical flushing of urination
2. IgA in urinary mucosa
3. Urine chemistry = acidity, lysozymes, lactoferrin
4. Surface proteins are different from other epitheliums

10

What are the 3 major threats to the urinary tract system?

Normal Biota (often from GI)
Catheters
Glomerular Nephritis (strep pyogenes)

11

Does strep pyogenes from skin infection AND strep throat both cause damage to the kidneys?

YES!

12

What is the leading cause of both complicated and uncomplicated UTIs?

E. Coli

13

Second leading cause of UTIs, and common in young sexually active females?

Staph. saprophyticus

14

Are E. Coli strains that cause UTIs the same strains that cause diarrhea???

NO! THEY ARE NOT! E. coli strains that cause UTIs are NORMAL FLORA of the GI tract

15

Name two risk factors for UTIs

Sexual intercourse
Catheterization

16

What are the most common type of nosocomial (hospital-related) infections?

Catheter- related UTIs

17

Are UTIs common in children? When would you see a UTI in a child?

Not common. If see in child it is usually an anatomic or functional abnormality

18

UTIs more common in women or men? When would you see a UTI in a man?

more common in women
In men, usually underlying urinary tract abnormality = obstruction from an enlarged prostate

19

Define selective media

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

20

Define differential media

contains an indicator, usually a dye, that detect particular chemical reactions occurring during growth

21

How do you distinguish staph from strep?

Catalase test!
Staph is catalase +
Strep is catalase -

22

What does catalase enzyme do?

Converts hydrogen peroxide to water and oxygen

23

How do you perform a catalase test?

Putting a small inoculum of bacteria into hydrogen peroxide.

With catalase present there is a rapid release of oxygen bubbles

24

How do you differentiate Staph aureus from Staph saprophyticus?

Coagulase test
Staph Aureus = coagulase +
Staph Sapro = coagulase -

25

What are you looking for in a coagulase test?

-Bound coagulase (clumping factor) is bound to bacterial wall
-It reacts with fibrinogen and results in precipitation of fibrinogen on staph cells
-This causes cells to clump with bacterial suspension is mixed with plasma

26

How do you determine Staph epidermidis from Staph saprophyticus?

Both are catalase positive and coagulase negative

Look at sensitivity to novobiocin!

Sapro = resistant
Epidermidis = sensitive

27

MOA of novobiocin?

Inhibits bacterial DNA gyrase in susceptible organisms

28

Gram + cocci
Catalse +
Coagulase -
Novobiocin RESISTANT

Staph Saprophyticus

29

When would you use flurorquinolones like ciprofloxacin?

Only use with severe symptoms and allergy to 1st line treatments OR
Bactrim was used in the last 3 months for UTI OR bactrim resistance in area is greater than 20%

30

What is the specific 1st line treatment for S. saprophyticus but is NOT suppose to be used empirically?

Amoxicillin/clavulanate

31

Gamma hemolysis bug (no clearing)

Staph saprophyticus

32

What colonies appear yellow with beta hemolysis when grown on blood agar?

Staph aureus

33

Describe MacConkey agar

Promotes growth of gram neg (and inhibits gram +)

Determines if they can ferement lactose

If you can ferment lactose colonies will appear pink

If you cannot ferment lactose the colonies will by colorless/translucent

34

Gram negative bacteria
Oxidase negative
Indole positive
Round pink circular colonies on MacConkey agar (can ferment lactose)

E. Coli

35

What protein chelates iron away from microorganisms that like to use iron for their ATP-generating reactions?

Lactoferrin

36

What component of our urinary tract inhibits most microorganisms from colonizing?

Surface proteins on epithelial cells

37

Why is urine cloudy in a UTI?

presence of WBCs and bacteria

38

What are the 2 names we use to differentiate categories of E. Coli that cause UTIs vs. diarrhea?

Uropathogenic E. Coli = UPEC
Extraintestinal E. Coli = ExPEC

39

What type of hemolysis does Staph saprophytic have?

Gamma hemolysis

40

Post-antibiotic course, itching, burning, vaginal discharge that is white like cottage cheese. WHat is the infection?

Candida Albicans Yeast Infection

41

What does Trichomonas discharge look like?

Yellow-frothy dischare

42

What type of hemoysis does staph aureus have?

Beta hemolysis

43

What kind of agar would you grow Klebsiella on?
What test would you then do to differentiate it from E. Coli?

MacConkey agar
Indole testing (Klebsiella is indole negative)