question
microorganisms
answer
Small, living organisms not visible to the naked eye
question
Pathogens
answer
Microorganisms that cause disease states
question
Non-pathogens
answer
Microorganisms that do not cause disease
May be beneficial
May be beneficial
question
Bacteria
answer
Free-living, single celled organism
question
Virus
answer
Intracellular organism, incapable of reproducing outside of the cell
question
Prion
answer
Infectious agent composed of proteinaceous material
question
Fungi
answer
Eukaryotic organisms, single or multicellular, often found in soil or on plant matter
question
Protozoa
answer
Single celled organisms, often colonizing moist environments
question
Pathogenesis
answer
Ability of a microbe to produce disease
question
True pathogens
answer
organisms able to cause disease in a healthy immune-competent individual
question
Opportunistic pathogens
answer
organisms that cause disease in immune-compromised individuals
question
Virulence
answer
Relative ability of a microorganism to cause disease or the degree of pathogenicity
question
Saprophytes
answer
Free-living organism that grows on dead or decaying organic material
Generally unable to produce disease
Generally unable to produce disease
question
Parasites
answer
Survive on living host & derive nutrition from the host without any benefit to the host
Cannot survive independently
Cannot survive independently
question
Commensal Parasite
answer
harmless parasite
Derive nutrition from the host without changing the host state
Survive on secretions & waste products of the host
Constitute normal microbial flora
Derive nutrition from the host without changing the host state
Survive on secretions & waste products of the host
Constitute normal microbial flora
question
Pathogen
answer
harmful parasite
Microorganism that derives nutrition from the host while causing a disease state
Require complex organic substances for nutrition
Microorganism that derives nutrition from the host while causing a disease state
Require complex organic substances for nutrition
question
Ectoparasite
answer
live on the surface of a host
question
Endoparasite
answer
live inside a host
question
Obligate parasite
answer
cannot exist without a host
question
Facultative parasite
answer
may exist without a host
question
Physical barriers to infection
answer
Intact, healthy skin
Stratified & cornified epithelium
Normal microbial flora
Low pH
Stratified & cornified epithelium
Normal microbial flora
Low pH
question
physical Ocular defense mechanisms
answer
Intact epithelium
Low conjunctival & corneal temperature
Conjunctival lymphoid elements
Low conjunctival & corneal temperature
Conjunctival lymphoid elements
question
Cleansing mechanisms
answer
Sloughing of outer skin layer
Bodily fluids
Bodily fluids
question
Ocular cleansing mechanisms
answer
Normal lid/tear film function
Wash away debris / microbes
Contain IgA & lysozyme
Wash away debris / microbes
Contain IgA & lysozyme
question
• Enzymes
answer
Lysozyme
question
Antibodies
answer
IgA
question
β-lysins
answer
Low molecular weight cationic proteins
question
Normal microbial flora
answer
Prevent colonization by organisms by blocking sites & nutrients
Production of bacteriocin: Proteinaceous toxins that inhibit growth of similar bacteria
Production of metabolic by-products creating a harmful microenvironment
Production of bacteriocin: Proteinaceous toxins that inhibit growth of similar bacteria
Production of metabolic by-products creating a harmful microenvironment
question
Phagocytosis
answer
Chemotaxis
Attachment
Ingestion
Killing
Elimination
Attachment
Ingestion
Killing
Elimination
question
Inflammation / Immune response
answer
Bodies response to injury or foreign body
Accumulation of a large number of phagocytic cells
Accumulation of a large number of phagocytic cells
question
Microbial resistance factors to host defenses
answer
Ability to resist phagocytosis
Surface structures
Intracellular survival & proliferation
Production of toxins & enzymes
Surface structures
Intracellular survival & proliferation
Production of toxins & enzymes
question
Ability to resist phagocytosis
answer
Masks the cell surface structures
No recognition as a foreign substance occurs
Release of cytotoxic chemicals
Inhibit chemotaxis
No recognition as a foreign substance occurs
Release of cytotoxic chemicals
Inhibit chemotaxis
question
Surface structures
answer
Adhesins - structures that mediate adherence of microbe to the host cell
question
Invasion
answer
Ability to penetrate & grow in tissues
question
Dissemination
answer
Spread of organisms to a distant site
question
Toxins
answer
Poisonous substances produced by organisms to interact with host cells, disrupting normal
metabolism and cause harm
metabolism and cause harm
question
Exotoxins
answer
Produced by gram (+) & (-) bacteria
Secreted by organism into extracellular environment or by cell lysis
Allow direct spread of microorganism
Production of enzymes to aid in microbial spread
Secreted by organism into extracellular environment or by cell lysis
Allow direct spread of microorganism
Production of enzymes to aid in microbial spread
question
• Endotoxins
answer
Gram (-) bacteria only
No enzymatic activity
No specificity in their activity against the host
No enzymatic activity
No specificity in their activity against the host
question
Adhesion
answer
Adhesins
Fimbriae (pili)
• Facilitate adherence of microbe to host cells
Fimbriae (pili)
• Facilitate adherence of microbe to host cells
question
Primary infection
answer
First infection by a microorganism
question
Reinfection
answer
Subsequent infection by same organism