Opportunistic infection

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Opportunistic infection
Classification and external resources
MeSH	D009894

An opportunistic infection is an infection caused by pathogens, particularly opportunistic pathogens—those that take advantage of certain situations—such as bacterial, viral, fungal or protozoan infections that usually do not cause disease in a healthy host, one with a healthy immune system. A compromised immune system, however, presents an "opportunity" for the pathogen to infect.

Causes

Immunodeficiency or immunosuppression can be caused by:

• Malnutrition
• Recurrent infections
• Immunosuppressing agents for organ transplant recipients
• Advanced HIV infection
• Chemotherapy for cancer
• Genetic predisposition
• Skin damage
• Antibiotic treatment
• Medical procedures
• Pregnancy

Types of infections

Further information: Immunodeficiency

These infections include:

• Acinetobacter baumanni
• Aspergillus sp.
• Candida albicans
• Clostridium difficile
• Cryptococcus neoformans
• Cryptosporidium
• Cytomegalovirus
• Geomyces destructans
• Histoplasma capsulatum
• Isospora belli
• Polyomavirus JC polyomavirus, the virus that causes Progressive multifocal leukoencephalopathy.
• Kaposi's Sarcoma caused by Human herpesvirus 8 (HHV8), also called Kaposi's sarcoma-associated herpesvirus (KSHV)
• Legionnaires' Disease (Legionella pneumophila)
• Microsporidium
• Mycobacterium avium complex (MAC) (Nontuberculosis Mycobacterium)
• Pneumocystis jirovecii, previously known as Pneumocystis carinii f. hominis
• Pseudomonas aeruginosa
• Staphylococcus aureus
• Streptococcus pyogenes
• Toxoplasma gondii

Treatment

Treatment depends on the type of opportunistic infection, but usually involves different antibiotics.

Veterinary treatment

Opportunistic infections caused by Feline Leukemia Virus and Feline immunodeficiency virus retroviral infections can be treated with Lymphocyte T-Cell Immune Modulator.