UTI Micro- Debiel

Question 1

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

Answer 1

Widespread E. coli resistance rates above 20 percent!

Question 2

What is the key feature distinguishing cystitis and pyelonephritis?

Answer 2

Pyelonephritis will have a fever

Question 3

Only members of what bacterial family convert nitrate to nitrite?

Answer 3

Enterobacteriaceae (E. Coli)

Question 4

What is the gold standard for diagnosing UTI?

Answer 4

Detection of bacteria in urine culture

Question 5

First line treatments for uncomplicated cystitis?

Answer 5

Nitrofurantoin

Bactrim (Trimethoprim/sulfamehtoxazole)

Question 6

First line treatment for acute uncomplicated pyelonephritis?

Answer 6

Fluoroquinolones (ciprofloxacin, levofloxacin)

OR

Bactrim or Ceftriaxone

Question 7

What is the central pathogenesis for catheter associated UTIs?

Answer 7

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

Question 8

What are three phrophylactic strategies for UTI management?

Answer 8

Continuous Antibiotics
Postcoital antibiotics
Patient- initiated therapy

Question 9

What are the 4 general defenses of the urinary tract?

Answer 9

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

Question 10

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

Answer 10

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

Question 11

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

Answer 11

YES!

Question 12

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

Answer 12

E. Coli

Question 13

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

Answer 13

Staph. saprophyticus

Question 14

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

Answer 14

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

Question 15

Name two risk factors for UTIs

Answer 15

Sexual intercourse

Catheterization

Question 16

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

Answer 16

Catheter- related UTIs

Question 17

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

Answer 17

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

Question 18

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

Answer 18

more common in women

In men, usually underlying urinary tract abnormality = obstruction from an enlarged prostate

Question 19

Define selective media

Answer 19

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

Question 20

Define differential media

Answer 20

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

Question 21

How do you distinguish staph from strep?

Answer 21

Catalase test!
Staph is catalase +
Strep is catalase -

Question 22

What does catalase enzyme do?

Answer 22

Converts hydrogen peroxide to water and oxygen

Question 23

How do you perform a catalase test?

Answer 23

Putting a small inoculum of bacteria into hydrogen peroxide.

With catalase present there is a rapid release of oxygen bubbles

Question 24

How do you differentiate Staph aureus from Staph saprophyticus?

Answer 24

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

Question 25

What are you looking for in a coagulase test?

Answer 25

- 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

Question 26

How do you determine Staph epidermidis from Staph saprophyticus?

Answer 26

Both are catalase positive and coagulase negative Look at sensitivity to novobiocin! ``` Sapro = resistant Epidermidis = sensitive ```

Question 27

MOA of novobiocin?

Answer 27

Inhibits bacterial DNA gyrase in susceptible organisms

Question 28

Gram + cocci Catalse + Coagulase - Novobiocin RESISTANT

Answer 28

Staph Saprophyticus

Question 29

When would you use flurorquinolones like ciprofloxacin?

Answer 29

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%

Question 30

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

Answer 30

Amoxicillin/clavulanate

Question 31

Gamma hemolysis bug (no clearing)

Answer 31

Staph saprophyticus

Question 32

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

Answer 32

Staph aureus

Question 33

Describe MacConkey agar

Answer 33

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

Question 34

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

Answer 34

E. Coli

Question 35

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

Answer 35

Lactoferrin

Question 36

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

Answer 36

Surface proteins on epithelial cells

Question 37

Why is urine cloudy in a UTI?

Answer 37

presence of WBCs and bacteria

Question 38

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

Answer 38

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

Question 39

What type of hemolysis does Staph saprophytic have?

Answer 39

Gamma hemolysis

Question 40

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

Answer 40

Candida Albicans Yeast Infection

Question 41

What does Trichomonas discharge look like?

Answer 41

Yellow-frothy dischare

Question 42

What type of hemoysis does staph aureus have?

Answer 42

Beta hemolysis

Question 43

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

Answer 43

``` MacConkey agar Indole testing (Klebsiella is indole negative) ```