Ex. 25 Urine Culture Techniques

Exam 3 Material

Describe 3 ways in which urinary tract infections may be acquired

1. Bacteria travel from the urethra to the bladder (ascending route)

2. Bacteria are introduced from a medical device (ascending route) — this is the most common

3. Bacteria travel through the blood to the kidneys (descending route)

Cystitis

Infection in the urinary bladder

pyelonephritis

Infection in the kidneys/kidney infection

ureter

tube between the kidney and bladder

urethra

Tube from bladder to the outside of the body

nephron

channel where filtration, reabsorption, and secretion are accomplished

glomerulus

interface of blood and nephron

What bacteria typically cause urinary tract infections?

• Gram-negative rods (enterics)

  • E. coli

  • Psuedomonas

  • Enterococci

• Gram-positive cocci

  • S. aureus & S. saprophiticus

• Yeasts

• Gram-positive rods — usually from descending infections

What laboratory media is used to culture urinary pathogens

BAP, MAC, and/or CNA

What are the quantitative inoculation techniques?

Ways to see the amount of bacterial colonies per a certain amount of urine.

Example:

15 colonies / 0.01 mL of urine = 1,500 colonies/mL

How do you interpret the quantitative methods of urinary culture results?

15 colonies / 0.01 mL of urine = 1,500 colonies/mL

This means that for every 0.01 mL of urine, there are 1,500 bacterial colonies

What urine dipstick test results would indicate a urinary tract infection?

Positive for:

• Leukocytes

• Blood

• Nitrates

• Protein — usually not by itself, though!

What are 3 ways that urine specimens can be acquired?

1. Clean catch — outside region is cleaned to avoid contaminating the sample

2. Catheter specimen — less worry about contamination

3. Exterior Collection Bag — usually used with infants and very young children

4. Suprapubic aspiration — puncture the abdomen and aspirate urine from the bladder. Usually used with infants, very young children, and sometimes adults

What are some infection complications the elderly face?

• delirium

• A higher frequency of infection due to other health complications