Bacterial infection of the host

Infection Process

The series of steps that pathogens follow to establish an infection, including exposure, adherence, invasion, and multiplication.

Disease Process

The progression of disease following infection, characterized by toxicity or invasiveness and resulting in tissue or systemic damage.

Exposure

The entry points for pathogens, which include the respiratory tract, gastrointestinal tract, urogenital tract, and breaks in the skin surface.

Mucous Membranes

Protective linings of the digestive, respiratory, and reproductive tracts that serve as a primary barrier and site of innate immune defense.

Lysozymes

Enzymes that hydrolyze the bonds in the sugar backbone of peptidoglycan, contributing to the immune defense at mucous membranes.

Mucociliary Clearance

A mechanism that helps expel inhaled microbes from the airways, aiding in respiratory defense.

Cationic Antimicrobial Peptides

Molecules that disrupt bacterial membranes, playing a role in the innate immune response.

Mucosa-associated Lymphoid Tissue (MALT)

Tissue that accumulates lymphocytes and contributes to immune responses at mucous membranes.

Adherence

The process by which bacteria attach to host cells, facilitated by structures like pili, fimbriae, capsules, and lipoproteins.

Type IV Pili

Hair-like projections on bacteria, such as Salmonella typhi, that enable attachment to host epithelial cells.

Biofilms

Aggregates of bacterial cells attached to surfaces and encased in a self-produced matrix, providing protection against the immune system and antibiotics.

Clinical Significance of Biofilms

Their ability to protect bacteria from immune responses and antibiotics, leading to chronic infections and treatment failures.

Tolerance Mechanisms

Strategies employed by bacteria in biofilms to resist antimicrobial agents, including restricted diffusion and reduced metabolic activity.

Invasion

The process by which bacteria enter host cells, triggering inflammatory responses and potentially leading to tissue damage.

Flagellar-mediated Motility

The movement of bacteria facilitated by flagella, which rotate to propel the cell through liquid environments.

Chemotaxis

The movement of bacteria in response to chemical gradients, characterized by biased random walks influenced by flagellar rotation.