A patient with a prosthetic heart valve develops subacute endocarditis caused by a coagulase-negative Staphylococcus. The organism is slime-producing, novobiocin-sensitive, and urease-negative. Which species is most likely?
- A Staphylococcus saprophyticus
- B Staphylococcus epidermidis ✓
- C Staphylococcus lugdunensis
- D Staphylococcus haemolyticus
Correct answer: B. Staphylococcus epidermidis
Explanation
S. epidermidis is novobiocin-sensitive, urease-negative, and produces biofilm/slime enabling it to colonise prosthetic devices and cause prosthetic valve endocarditis. S. saprophyticus is novobiocin-resistant and urease-positive, and primarily causes UTI in young women. S. lugdunensis, though coagulase-negative, causes aggressive native valve endocarditis. The combination of novobiocin sensitivity, urease negativity, and slime production best fits S. epidermidis.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.