Pathogenicity Mechanisms and Infectious Diseases

Flashcards covering key terms and definitions related to pathogenicity mechanisms and infectious diseases.

Pathogen

An agent able to evade the various physiological defences of the human host to cause infection.

Infection

When an infectious agent enters the body, increases in number, and causes damage to the host.

Commensalism

A relationship where the host and microbe live together with no effect on each other's life cycle.

Parasitism

An un-equal relationship where one benefits to the detriment of another; common in infections.

Symbiosis

A relationship where species live together for their mutual benefit, such as human hosts and gut flora.

Opportunistic infection

Infection occurring when healthy human defences are weakened, often seen in immunocompromised persons.

Nosocomial infection

Infections transmitted in hospitals, some may be opportunistic affecting seriously ill patients.

Exotoxins

Proteins released during bacterial growth that can damage cell membranes and inhibit protein synthesis.

Endotoxins

Lipopolysaccharides from the outer membrane of dead gram-negative bacteria that can cause inflammation.

Bacteraemia

Presence of bacteria in the blood due to failure of the body’s defence mechanisms.

Mycoplasma pneumoniae

A common cause of community-acquired pneumonia spread through respiratory droplets.

Viral infection

Infections caused by viruses, which rely on host cell machinery for replication.

Influenza virus

A respiratory viral illness causing significant global morbidity and mortality.

SARS-CoV-2 virus

The virus responsible for COVID-19, affecting the lower respiratory tract.

Sepsis

A life-threatening condition resulting from the body's response to infection, leading to organ dysfunction.

Opportunistic organism

An organism that generally does not cause disease in healthy individuals but can do so in immunocompromised hosts.