Be honest – do the cases in the lefthand table make you break into hives? It’s not an uncommon response! S. aureus is a sneaky bacterium, throwing susceptibility curve-balls like those to the left on a regular basis. Not to mention the non-aureus staphylococci, which we are now routinely identifying by the power of our MALDI-TOFs - Staphylococcus pseudintermedius, anyone? Despite the fact that the primary mechanism for oxacillin resistance (the mecA gene, which encodes PBP2a) is the same across all staphylococci, it manifests as slightly different phenotypes in different species. As a result, the Staphylococcus table in the Clinical and Laboratory Standards Institute (CLSI) M100S document has been a continual construction zone over the past decade, as we try to keep up with new species, new resistance mechanisms and new testing challenges. However, there is no arguing that accurate oxacillin susceptibility testing of the staphylococci is one of the most clinically meaningful tests performed by the laboratory. Study after study has demonstrated that infections caused by oxacillin-susceptible isolates are best treated with a beta-lactam, and vancomycin is a suboptimal choice for those infections. So, while it may not be not the sexiest topic to launch the Bugs and Drugs Blog, I thought it would be a topic to which we can all relate.