Flashcards in B2.052 The Microbial World Deck (57)
what are Koch's postulates?
1. the organism is regularly found in the lesion of the disease
2. the organism can be isolated in pure culture on artificial media
3. inoculation of this pure culture produces a similar disease in experimental animals
4. organisms can be recovered from the lesions in the animals
what did threat of ID decline in the 1900s?
sanitation and hygiene
chlorination of water
animal and pest control
why can diseases re-emerge?
evolution of microorganisms
intensive misuse of antibiotics (selection for the proliferation of resistant organisms)
decline in public health in some regions
increase in people with decreased immune function
what are the classes of infectious agents?
priors (infectious proteins)
rank microorganisms by size
what is the requirement in bacteria to be classified as the same species?
>97% identity in 16s rRNA
high degree of DNA sequence identity
more arbitrary than eukaryotes
chain of cocci
collection of cocci
funky shaped bacteria
coccobacillus: halfway between coccus and bacillus
what is unique about the spirochete shape?
predestined to penetrate tissues
what is a spore?
formed under stress conditions
can survive in suboptimal circumstances better than the bacteria themselves
allow colonies to survive
what is the function of a capsule?
more chronic infection
thick peptidoglycan cell wall
thin PG layer with a second membrane
lipopolysaccharides acyl chain linkages with second membrane
have lipoproteins expressed on membrane
thing PG layer
flagella in between membranes
cant be stained by gram staining
microorganism in symbiotic relationship with host
degree of pathogenicity
cause of disease
factors of disease spread
sporadic- small isolated cases
endemic- continually prevailing in a region
pandemic- worldwide outbreak
stages of infection disease
specific illness (localized or systemic)
what is prodrome
what is convalescense
after resolution of symptoms to complete recover there can be complications
-permanent tissue damage
how do you measure virulence
microbiome of skin
microbiome of respiratory tract
microbiome of GI
microbiome of GU
anterior urethra- lactobacilli
vagina- lactobacilli, others