Which trait characterizes most staphylococci and aids their isolation from clinical specimens?

• A. Bile resistance
• B. Growth at 55°C
• C. High salt tolerance
• D. Resistance to novobiocin

Answer: (C)

High salt tolerance is the defining trait here. Staphylococci are halotolerant and can grow in high osmolarity environments, which is why selective media containing salt, like Mannitol Salt Agar with about 7.5% NaCl, is used to isolate them from clinical specimens. The high salt inhibits many other bacteria, enriching staphylococci for easier detection. The other options don’t describe a general feature of most staphylococci: bile resistance isn’t typical of staph, growth at 55°C is beyond their usual range, and novobiocin resistance distinguishes only certain species (not most) of staphylococci.