Novobiocin susceptible Staphylococcus is
**Core Concept**
Novobiocin susceptibility is a key characteristic used to differentiate between coagulase-negative staphylococci, particularly Staphylococcus saprophyticus and other species. This test relies on the ability of novobiocin to inhibit the enzyme adenosine triphosphatase (ATPase) in susceptible bacteria.
**Why the Correct Answer is Right**
Staphylococcus saprophyticus is the only coagulase-negative staphylococcus that is susceptible to novobiocin. This susceptibility is due to the presence of a novobiocin-sensitive ATPase enzyme in this species. The novobiocin sensitivity test is a useful tool in clinical microbiology for identifying S. saprophyticus, which is often implicated in urinary tract infections.
**Why Each Wrong Option is Incorrect**
**Option A:** Other coagulase-negative staphylococci, such as Staphylococcus epidermidis and Staphylococcus haemolyticus, are generally resistant to novobiocin.
**Option B:** Coagulase-positive staphylococci, such as Staphylococcus aureus, can also exhibit novobiocin resistance.
**Option C:** Staphylococcus lugdunensis is another coagulase-negative species, but it is not typically susceptible to novobiocin.
**Clinical Pearl / High-Yield Fact**
When interpreting novobiocin susceptibility results, it is essential to consider the clinical context and other laboratory findings, as the test may not always be definitive in identifying S. saprophyticus.
**Correct Answer:** D. Staphylococcus saprophyticus