Infection (increased susceptibility)


Appropriate Tests

The causative organisms most frequently associated with the predisposing conditions are listed.

See also Immunodeficiency and Alcoholism


Infections are usually bacterial or fungal.

See also Neutropenia and Febrile neutropenia.

Pseudomonas aeruginosa


Escherichia coli


Klebsiella pneumoniae


Staphylococcus aureus


Streptococcus pyogenes


Candida spp

See Candidiasis.

Aspergillus spp

See Aspergillosis.

Mucor spp

See Mucormycosis.

Cell mediated (T cell) immune dysfunction

Particularly in patients on steroid and immunosuppressive therapy (eg, fludarabine); in those with HIV infection; and following transplantation.

Infections are commonly due to intracellular organisms, immunosuppressive treatment and steroid therapy.

Herpes simplex

See Herpes simplex virus infection.

Herpes zoster

See Varicella zoster infection.


See Cytomegalovirus infection.

Measles virus

See Measles.

Mycobacterium  spp

See Mycobacterial infection.

Nocardia spp

See under Pneumonia - immunocompromised host.

Salmonella spp


Legionella pneumophila

See under Pneumonia - atypical. See also Legionella infection.

Listeria monocytogenes

See Listeriosis.

Cryptococcus neoformans

See Cryptococcal infection.

Candida spp

See Candidiasis.

Pneumocystis jiroveci

See under Pneumonia - immunocompromised host.

Toxoplasma gondii

See Toxoplasmosis.

Cryptosporidium sp

See Cryptosporidial infection.

Strongyloides stercoralis


Humoral immune dysfunction

Deficient antibody production, particularly in patients with Plasma cell myeloma, Chronic lymphocytic leukaemia, Nephrotic syndrome, and primary immunodeficiencies (see Immunodeficiency).

Streptococcus pneumoniae


Haemophilus influenzae


Neisseria meningitidis

See Neisseria meningitidis (meningococcus).

Giardia intestinalis

See Giardiasis.

Complement deficiency and/or dysfunction

See under Immunodeficiency - primary.

Streptococcus pneumoniae

See under Pneumonia.

Neisseria meningitidis

See Neisseria meningitidis (meningococcus).

Neisseria gonorrhoeae


Neutrophil dysfunction

Infections are commonly due to organisms of low virulence.

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