California Cosmetology Written ExamSafety and Infection ControlMedium

A lab report describing a client's abscess after a manicure notes bacteria arranged in grape-like clusters. Which arrangement of cocci does this describe?

  1. AStreptococci (chains)
  2. BDiplococci (pairs)
  3. CStaphylococci (clusters)
  4. DBacilli (rods)
Show answer & explanation

Correct answer: C. Staphylococci (clusters)

Staphylococci grow in grape-like cluster formations and commonly cause localized infections such as abscesses, boils, and pustules. Streptococci form chains, diplococci form pairs, and bacilli are rod-shaped, not round cocci.

Why the other options are wrong

  • A. Streptococci grow in chain formations, associated with strep throat and blood poisoning.
  • B. Diplococci form pairs and cause diseases such as pneumonia and gonorrhea.
  • D. Bacilli are rod-shaped bacteria, not a cocci arrangement.

Staphylococci

Round bacteria (cocci) that grow in grape-like cluster formations, commonly causing abscesses, boils, and pustular infections.

  • Cluster arrangement resembles grapes
  • Cause localized skin infections/abscesses
  • Contrast with streptococci (chains) and diplococci (pairs)

Memory trick: 'Grapes cluster, chains link, pairs dance' — Staph=grapes, Strep=chains, Diplo=pairs.

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