Micro - UTI Flashcards Preview

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Flashcards in Micro - UTI Deck (15):
1

Urinary Tract Defenses

1. Urine flow = desquamation
2. Urine chemistry = acidity, lysozymes (blocks peptidoglycan), lactoferrin (binds iron)
3. Different cell surface proteins on epithelial cells in urinary vs GI
4. Secretory IgA (adaptive immune response)
5. Normal flora (prevent other microorganisms from colonizing)

2

Major Threats to Urinary System

1. Microorganisms from GI to Urinary tract --> community acquired
2. Catheters --> hospital acquired (nosocomial)
3. Immune dysfunction --> glomerular nephritis

3

Urethritis

infection of urethra

4

Cystitis

infection of bladder

5

Pyelonephritis

infection of kidney

6

UTI signs and symptoms

sudden onset, dysuria, urgency, cloudy urine (WBC, bacteria), hematurai (sloughing cells)
back pain indicates pyelonephritis

7

E. Coli

Main causative organism of UTIs
- NOT same E. Coli that causes GI problems

8

Acute infections of urinary tract

Risk factors: sex, catheterization
Children --> anatomic of functional abnormality

9

Pyelonephritis

Ascending infections
Flank pain, fever, dysuria, N/V, malaise

10

Culture Media

supplies nutritional needs of microorganisms
Selective = contains compounds that selectively inhibit growth of some microbes but not others
Differential = contains indicator, usually dye that detects particular chemical reactions occuring

11

Tell between Staph or Strep?

Catalase test (staph (+), strep (-))
catalase converts hydrogen peroxide to water and oxygen
rapid release of oxygen bubbles on media

12

Staph aureus or staph saprophyticus?

Coagulase test (aureus (+), sapro (-))
Bound coagulase reacts directly with fibrinogen --> clumping cells in suspension
Free coagulase is extracellular protein that causes the formation of clot

13

Staph epidemidis or staph saprophyticus?

Novobiocin test (sapro resistant, epi sensitive)
Novobiocin inhibits bacterial DNA gyrase in susceptible microorganisms

14

MacConkey Agar

Selective and Differential
- inhibits growth of gram (+) organisms
- indicates lactose fermentation

15

Indole Test

distinguishes E. Coli (+) from Klebsiella (-) based on ability to degrade tryptophan