Opportunistic infections

Last updated: Friday, 24, December, 2010
OrganismsAppropriate Tests

Immunodeficient patients are at particular risk of opportunistic infections and are also more susceptible to common pathogens.

An aggressive search for the responsible pathogen may include urine microscopy and culture, blood culture, aspiration of body fluids, endoscopic brushings or biopsies, other tissue or organ biopsies (with lesions on diagnostic imaging); cryptococcal antigen (serum); cytomegalovirus antibodies, Legionella spp antibodies and toxoplasma antibodies.

Consult pathologist for assistance with defining the appropriate testing strategy.

See Immunodeficiency, Infection (increased susceptibility)

Viral infection

Bacterial infection

  • Mycobacterium tuberculosis 

 See Tuberculosis

  • Atypical mycobacteria 

See Mycobacterial infection

  • Listeria monocytogenes

 See Listeriosis

  • Legionella pneumophila 

See Legionella infection

Fungal infection

  • Candida albicans 

See Candidiasis

  • Cryptococcus neoformans 

SeeCryptococcal infection

  • Mucor sp 

See Mucormycosis

  • Aspergillus spp 

See Aspergillosis

  • Pneumocystis jiroveci

See Pneumocystis infection

Protozoal infection

  • Toxoplasma gondii 

See Toxoplasmosis

  • Microsporidia 

Faeces - ova, cysts and parasites; examination for microsporidia must be specifically requested.

Helminthic infection 

Faeces - ova, cysts and parasites.

See also Worm infection
  • Strongyloides stercoralis 

Faeces - microscopy of fresh specimen; Harada culture for larvae (consult pathologist); Strongyloides sp antibodies.