If a staphylococcus spp. is negative for the slide coagulase test and novobiocin resistance, what should be performed next?

When a Staphylococcus species is negative for the slide coagulase test and novobiocin resistance, it indicates that the organism is likely not Staphylococcus aureus. To further characterize the isolate, additional tests are needed to narrow down the identification process.

Performing a tube coagulase test can provide more definitive results regarding the coagulase activity, which helps differentiate between Staphylococcus aureus and other coagulase-negative staphylococci. Some less pathogenic species could still produce a positive result in the tube test, which is necessary for comprehensive identification.

B-hemolysis on blood agar is also a relevant test. Certain staphylococci may exhibit B-hemolytic activity, which could help in determining the species. Hemolysis patterns can be significant for identifying organism types and their pathogenic potential.

Mannitol salt agar is designed to isolate staphylococci and differentiate those that can ferment mannitol, which is another characteristic feature of Staphylococcus aureus. Even though a negative slide coagulase test indicates a lower likelihood of it being S. aureus, this test can confirm if the organism is capable of growing in high salt concentrations and utilize mannitol.

Since these tests provide critical information regarding