Microbiology Flashcards
6 cards from real ASCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Microbiology flashcards as text
Which organism is the most common cause of community-acquired urinary tract infections?
Answer: Escherichia coli
Escherichia coli accounts for approximately 80–85% of community-acquired urinary tract infections.
A Gram stain showing gram-positive cocci in clusters is most consistent with:
Answer: Staphylococcus species
Staphylococci characteristically appear as gram-positive cocci in grape-like clusters on Gram stain.
Which test differentiates Staphylococcus aureus from coagulase-negative staphylococci?
Answer: Coagulase test
S. aureus produces coagulase, which clots plasma, while coagulase-negative staphylococci (e.g., S. epidermidis) do not.
Which medium is selective for gram-negative enteric pathogens like Salmonella and Shigella?
Answer: Hektoen enteric (HE) agar
Hektoen enteric agar inhibits gram-positive bacteria and differentiates enteric pathogens by lactose fermentation and H2S production.
The CAMP test is used to identify which organism?
Answer: Streptococcus agalactiae (Group B Strep)
Group B Streptococcus produces the CAMP factor that enhances beta-hemolysis of S. aureus, creating an arrowhead zone.
Which fastidious organism requires X (hemin) and V (NAD) factors and causes meningitis in children?
Answer: Haemophilus influenzae
Haemophilus influenzae requires both hemin (factor X) and NAD (factor V) for growth and was a major cause of pediatric meningitis before vaccination.