Candida infection: This is the most likely diagnosis because Candida species are common causes of prosthetic joint infections, especially in patients with compromised immune systems or those who have undergone recent surgery. The presence of a spacer after prosthesis removal increases the risk of Candida infection due to the device's presence in the joint.

Aspergillus infection: Aspergillus species can cause infections in immunocompromised patients and those with prosthetic devices. Although less common than Candida, Aspergillus infections can be severe and should be considered in the differential diagnosis.
Cryptococcal infection: Cryptococcus neoformans can cause infections in immunocompromised patients, including those with prosthetic joints. While less common than Candida or Aspergillus, Cryptococcal infections can be severe and should be considered.

Histoplasma capsulatum infection: Although rare, Histoplasma capsulatum can cause severe infections in immunocompromised patients, including those with prosthetic joints. Missing this diagnosis could lead to severe consequences, including sepsis and death.
Blastomyces dermatitidis infection: Similar to Histoplasma, Blastomyces dermatitidis can cause severe infections in immunocompromised patients. This diagnosis should not be missed due to the potential for severe consequences.

Trichosporon infection: Trichosporon species are rare causes of infections in humans but can cause severe disease in immunocompromised patients. While rare, Trichosporon infections should be considered in patients with prosthetic joints and spacer devices.
Scedosporium infection: Scedosporium species are rare causes of infections in humans but can cause severe disease in immunocompromised patients. This diagnosis should be considered in patients with prosthetic joints and spacer devices, especially those with compromised immune systems.