Final answer:
To investigate gram-negative folliculitis, a sample from the infected site is taken and a Gram stain is performed to differentiate bacteria. If gram-negative bacteria are present, cultures on TSA plates and biochemical tests are used for identification. Findings inconsistent with gram-negative bacteria require further testing.
Step-by-step explanation:
To investigate gram-negative folliculitis, it is important to identify the specific bacteria causing the infection. This starts with collecting a sample from the infected site and performing a Gram stain, which differentiates gram-positive from gram-negative bacteria. Under the microscope, gram-negative bacteria do not retain the crystal violet stain and instead, appear pink after a counterstain is applied. In the case of folliculitis, looking for bacteria that can cause infections around hair follicles, such as certain classes of Proteobacteria, would be the focus.
Culture methods can also be used to grow the bacteria and help in identifying them. Typically, a medium like Tryptic Soy Agar (TSA) is used to plate out the bacteria and allow them to grow overnight. Once growth has occurred, the bacteria can be subjected to various biochemical tests to confirm their identity.
Furthermore, if the Gram stain indicates grape-like clusters of spherical cells, this suggests a gram-positive organism, such as Staphylococcus, which is inconsistent with gram-negative folliculitis. In such a case, additional tests and cultures would be needed to confirm the presence of gram-negative bacteria and to rule out other potential causes of the skin condition.