Knowra Opportunistic infection Opportunistic infection An infection caused by a pathogen that exploits weakened immune defenses or conditions that normally prevent disease. It may arise from organisms already present in the body or acquired from the environment.
Immunocompromised state : A condition in which immune defenses are impaired or suppressed, increasing susceptibility to infection. Reduced immune function removes checks that ordinarily contain opportunistic pathogens.
Pneumocystis pneumonia : A pneumonia caused by the fungus Pneumocystis jirovecii, especially in people with impaired cellular immunity. It is a classic AIDS-defining infection and may signal severe immune suppression.
Innate immunity : The body's rapid, broadly acting defenses against infection, including barriers, phagocytes, and complement. Defects in innate defenses can permit invasive fungal and bacterial infections.
Primary pathogen : A pathogen capable of causing disease in a healthy host with intact defenses. Unlike opportunists, primary pathogens need not depend on a preexisting immune defect.
Immunosuppression : The reduction of immune-system activity by disease, medication, or medical treatment. Transplant drugs and cancer therapies can create the conditions for opportunistic infections.
Candidiasis : An infection caused by Candida yeasts, ranging from superficial disease to invasive infection. Candida can overgrow after antibiotics or cause invasive disease in immunocompromised patients.
Adaptive immunity : Antigen-specific immunity mediated by B cells, antibodies, and T cells. Loss of T-cell function particularly raises risk from several intracellular and fungal pathogens.
Community-acquired infection : An infection acquired outside a hospital or other healthcare setting. Acquisition setting does not itself imply opportunism; community infections can affect healthy hosts.
Microbiome : A community of microorganisms living in a particular environment, including the human body. Antibiotics can disrupt protective microbial communities and let opportunistic species expand.
Cytomegalovirus infection : An infection caused by cytomegalovirus, which can persist latently and reactivate later. Reactivation after transplantation can damage the retina, lungs, gut, or other organs.
Show all 22