CLT CLT Microbiology & Urinalysis 1

Question 1

Which culture medium is selective for gram-negative enteric bacteria and inhibits gram-positive organisms?

Accepted Answer

MacConkey agar

Answer

Blood agar

Answer

Chocolate agar

Answer

Sabouraud dextrose agar

Question 2

A urine culture grows >100,000 CFU/mL of a single organism. How should this result be interpreted?

Accepted Answer

Significant bacteriuria consistent with urinary tract infection

Answer

Contamination

Answer

Normal flora

Answer

Requires repeat culture only

Question 3

In the Gram stain procedure, what is the purpose of the decolorization step using acetone-alcohol?

Accepted Answer

To remove the crystal violet-iodine complex from gram-negative cells

Answer

To fix bacteria to the slide

Answer

To counterstain gram-positive cells

Answer

To lyse the bacterial cell wall

Question 4

Which organism is the most common causative agent of urinary tract infections in otherwise healthy women?

Accepted Answer

Escherichia coli

Answer

Staphylococcus aureus

Answer

Klebsiella pneumoniae

Answer

Pseudomonas aeruginosa

Question 5

What does a positive catalase test result (bubbling with hydrogen peroxide) indicate about a gram-positive coccus?

Accepted Answer

It is a Staphylococcus species

Answer

It is a Streptococcus species

Answer

It is anaerobic

Answer

It ferments glucose

Question 6

Which component of a routine urinalysis evaluates the kidney's ability to concentrate urine?

Accepted Answer

Specific gravity

Answer

pH

Answer

Protein

Answer

Glucose