Host Flashcards
Biological relationship between two or more organisms where broth benefit from one another
Symbiosis
Organism benefits but there is no beneficial or harmful effects to the host
Commensalism
The microbe benefit at the expense of the other host
Parasitism
Commonly found in body sites of healthy persons
Flora
Microorganisms that colonize an area for months or years
Resident Flora
Present at a site temporarily, eliminated by host immune defense/competition with resident flora
Transient Flora
Gastrointestinal tract: sites
urethra and vagina
Gastrointestinal Tract: Sterile
Kidneys, bladder and fallopian tubes
Cause disease when their habitat is damaged, disturbed or changed by trauma or; when the hosts immune system is weakened or compromised
Opportunists
Is the ability of a microbe to produce disease in a susceptible individual
Pathogenesis
Is the relative ability of a microorganism to cause disease or the degree of pathogenecity
Virulence
Microorganisms that can kill phagocyte
Staphylococcus and Streptococcus
Microorganisms that can resist phagocytosis
H. influenzae
P. aeruginosa
E. coli
S. typhi
Cell surface structures that mediate attachment
Adhesins
Poisonous substances produced by organisms that interact with host cells, disrupting normal metabolism and causing harm
Toxins
Secreted by the organism into the extracellular environment
Toxin Gene is commonly encoded by phages, plasmids or transposons
Exotoxins
A constituent Lipid A of the outer membrane of gram (-) bacteria
Released upon lysis of the organism
Endotoxins
I. Skin epithelium presents as mechanical barrier
II. Microbial flora compete for nutrients and produce bactericidal substances
III. Microbial flora and Sebaceous gland contribute to low pH
Physical Barriers
