Pitfalls in the routine diagnosis of Staphylococcus aureus

Two hundred isolates of Presumed Staphylococcus aureus clinical specimens, collected from two government hospitals in, Saudi Arabia, had their identity verified. We used the tube test as our gold standard. Twenty (10%) of the isolates were -identified. Reliance by the two laboratories on DNase test, fermentation reaction and improper performance of the test, were responsible for the mis-diagnosis.