Microbial Mechanisms of Pathogenicity

These flashcards cover essential concepts regarding microbial mechanisms of pathogenicity, detailing the definitions, functions, and characteristics of various pathogenic processes.

What is pathogenicity?

The ability to cause disease.

What is virulence?

The degree of pathogenicity.

What are the portals of entry for microorganisms?

Mucous membranes, skin, and parenteral route.

What does ID50 measure?

The infectious dose for 50% of a sample population.

What does LD50 measure?

The lethal dose for 50% of a sample population.

What is adherence in terms of pathogens?

The process by which almost all pathogens attach to host tissues.

What are adhesins?

Ligands on the pathogen that bind to receptors on host cells.

How do capsules assist pathogens?

They impair phagocytosis.

What are biofilms and their role in pathogens?

Biofilms help evade phagocytosis and provide antimicrobial resistance.

What role do siderophores play in microbial pathogenicity?

Siderophores bind iron more tightly than host cells, providing necessary nutrients for bacteria.

What is the function of coagulases?

They coagulate fibrinogen forming fibrin.

What are exotoxins?

Poisonous substances produced and secreted by microorganisms.

What is the difference between exotoxins and endotoxins?

Exotoxins are usually proteins secreted by bacteria, while endotoxins are part of the lipopolysaccharides of gram-negative bacteria.

What causes fever in response to endotoxins?

Cytokines released by macrophages induce the hypothalamus to produce prostaglandins.

What type of toxin causes skin and soft tissue infections by making pores in white blood cell membranes?

Membrane-disrupting exotoxins.

What is antigenic variation?

When pathogens alter their surface antigens, making host antibodies ineffective.

What are cytopathic effects (CPE)?

Visible effects of viral infection on a cell, including disruption and inclusion bodies.

Which fungi produce carcinogenic toxins?

Aspergillus produces aflatoxin.