Flashcards in 63/65-C. Diff and Meningitis Exemplar Deck (58)
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1
microbial exposure is constant
but clinical infection is rare
2
5 obligatory capabilities of microbes
attachment
spread
replication
evasion
transmission
3
risk of infection
dose*virulence
_____________
host resistence
4
dose
number of organisms
5
virulence
sum of organisms properties that help it cause infection
6
resistance
resistance of the host to infection, depending on anatomy and immune system
7
infection earlier in sequence
reliance on preformed effector molecules using non specific recognition molecules
8
infection later in sequence
synthesis of effector molecules, depends on specific recognition molecules
9
time for barrier
0-4 hours
10
time for innate
4-96 hours
11
time for adaptive
96+ hours
12
stages of infection
adherence
penetration
local infection
lymphatic spread
adaptive immunity
13
clinical reasoning
mechanisms
clinical presentation
context
14
inflammation in colon
increase mucous, peristalsis, bleeding
15
types of barriers
mechanical, physical, chemical, microbiome
16
epithelial cells
tight junctions, don't leak
17
barriers to infection
non-specific
use preformed effector molecules so response is fast
use antimicrobial peptides (defensins)
18
chemical protection of gut
low pH
enzymes
antimicrobial peptides
19
antimicrobial peptides
defensins, cathelicidin, regIII
punch holes in bacterial membrane to kill
20
GI host defense
low pH, acidity
motility
mucous
bacterial colonization
GI mucosal immunity
21
GI mucosal immunity
sIgA and IgG
lymphoid follicles
Peyer's patches
M cells
22
microbiome
all microbes, their genome, and environmental interactions
important for GI function and overall health
23
development of microbiology of GI tract
Sterile at birth
becomes colonized with maternal flora
initial colonization: aerobic (lactobacilli), create reducing environment
subsequent colonization: anaerobic
24
gut becomes colonized with commensal bacteria
mucosal becomes anti inflammatory
if infected it shifts to pro inflammatory
25
gut bacteria
outnumbers human cells 10x
quantity varies along GI tract (more at end)
Humans rely on gut bacteria
26
functions of gut bacteria
metabolic functions-breakdown sugars, produce vitamins
educate immune system
27
mucosa associated microbes
commensal symbionts
bidirectional induction of gene expression (microbe influence human and vice versa)
metabolism
nutrition
immune (anti inflammatory)
28
tight junctions
IL-10: anti inflammatory
IL-17: inflammatory, leaky
29
ID50
# or organisms needed to cause disease in 50%
30
