63/65-C. Diff and Meningitis Exemplar

Question 1

microbial exposure is constant

Answer 1

but clinical infection is rare

Question 2

5 obligatory capabilities of microbes

Answer 2

attachment
spread
replication
evasion
transmission

Question 3

risk of infection

Answer 3

dose*virulence
_____________
host resistence

Question 4

dose

Answer 4

number of organisms

Question 5

virulence

Answer 5

sum of organisms properties that help it cause infection

Question 6

resistance

Answer 6

resistance of the host to infection, depending on anatomy and immune system

Question 7

infection earlier in sequence

Answer 7

reliance on preformed effector molecules using non specific recognition molecules

Question 8

infection later in sequence

Answer 8

synthesis of effector molecules, depends on specific recognition molecules

Question 9

time for barrier

Answer 9

0-4 hours

Question 10

time for innate

Answer 10

4-96 hours

Question 11

time for adaptive

Answer 11

96+ hours

Question 12

stages of infection

Answer 12

adherence
penetration
local infection
lymphatic spread
adaptive immunity

Question 13

clinical reasoning

Answer 13

mechanisms
clinical presentation
context

Question 14

inflammation in colon

Answer 14

increase mucous, peristalsis, bleeding

Question 15

types of barriers

Answer 15

mechanical, physical, chemical, microbiome

Question 16

epithelial cells

Answer 16

tight junctions, don’t leak

Question 17

barriers to infection

Answer 17

non-specific
use preformed effector molecules so response is fast
use antimicrobial peptides (defensins)

Question 18

chemical protection of gut

Answer 18

low pH
enzymes
antimicrobial peptides

Question 19

antimicrobial peptides

Answer 19

defensins, cathelicidin, regIII

punch holes in bacterial membrane to kill

Question 20

GI host defense

Answer 20

low pH, acidity
motility
mucous
bacterial colonization
GI mucosal immunity

Question 21

GI mucosal immunity

Answer 21

sIgA and IgG
lymphoid follicles
Peyer’s patches
M cells

Question 22

microbiome

Answer 22

all microbes, their genome, and environmental interactions

important for GI function and overall health

Question 23

development of microbiology of GI tract

Answer 23

Sterile at birth
becomes colonized with maternal flora
initial colonization: aerobic (lactobacilli), create reducing environment
subsequent colonization: anaerobic

Question 24

gut becomes colonized with commensal bacteria

Answer 24

mucosal becomes anti inflammatory

if infected it shifts to pro inflammatory

Question 25

gut bacteria

Answer 25

outnumbers human cells 10x quantity varies along GI tract (more at end) Humans rely on gut bacteria

Question 26

functions of gut bacteria

Answer 26

metabolic functions-breakdown sugars, produce vitamins | educate immune system

Question 27

mucosa associated microbes

Answer 27

``` commensal symbionts bidirectional induction of gene expression (microbe influence human and vice versa) metabolism nutrition immune (anti inflammatory) ```

Question 28

tight junctions

Answer 28

IL-10: anti inflammatory | IL-17: inflammatory, leaky

Question 29

ID50

Answer 29

or organisms needed to cause disease in 50%

Question 30

ID 50 in gut

Answer 30

lots needed for infection fewer needed if passed through skin barrier antibiotics clear microbiome and decrease ID50 by 30,000x

Question 31

decrease ID 50

Answer 31

break barrier, antibiotics to clear microbiome, exposure to new bacteria

Question 32

C. diff

Answer 32

lives as a spore | produce cytotoxins A and b

Question 33

causes of C diff

Answer 33

old age Hospitalization medications - broad spectrum, proton pump inhibitors, chemotherapeutic drugs

Question 34

4 forms of c diff

Answer 34

short term colonization acute diarrhea recurrent diarrhea fulminant diarrhea

Question 35

symptoms of c diff

Answer 35

``` fever cramping adb pain bloody diarrhea fecal PMN ```

Question 36

Antibiotics and c diff

Answer 36

disrupt microbiome

Question 37

PPI and c diff

Answer 37

lower gastric pH so microbes can grow

Question 38

chemotherapeutic agents

Answer 38

disrupt GI epithelium

Question 39

treatment for c diff

Answer 39

fecal transplant | vancomycin or metronidazole

Question 40

increase risk of GI infection

Answer 40

foods or meds that neutralize or reduce gastric acid secretion pernicious anemia gastrectomy

Question 41

Petechiae

Answer 41

non blanching, tiny red spots | extravasation of blood from capillaries

Question 42

purpura

Answer 42

large, dark irregular shaped lesions | significant bleeding into soft tissue

Question 43

ecchymoses

Answer 43

coalesced purpura

Question 44

left shift

Answer 44

marrow is stressed and releasing immature cells

Question 45

n. meningitidis

Answer 45

gram negative coccus

Question 46

structure of meningococcal cell wall

Answer 46

lipopolysaccharide for exotoxin pilus for attachment capsule with negative charge

Question 47

pili

Answer 47

specific attachment to non ciliated nasopharyngeal cells or damage to ciliated cells

Question 48

Lipopolysaccharide

Answer 48

LPS and CD14 form complex recognized by TLR and causes inflammation with NF-kB Cytokine release for T cell mediated immunity, B cell humoral immunity, or sepsis

Question 49

hallmark of inflammation and infection

Answer 49

leukocytes and left shift

Question 50

serum protein during inflammation

Answer 50

normal albumin>globulin | infection albumin

Question 51

local inflammation in infection

Answer 51

increased permeability

Question 52

systemic protective actions in infection

Answer 52

brain-fever liver-acute phase proteins bone marrow-leukocyte production (increase PMN, left shift)

Question 53

systemic pathologic effects in inflammation

Answer 53

heart-low output, low BP (renal failure), increased o2 demand (hypoxia), acidosis blood vessel-increased permeability, vasodilation, leaky vessels, petechia and purpura

Question 54

capsule on bacteria

Answer 54

fight with anticapsular antibody

Question 55

greatest risk for bacterial meningitis

Answer 55

first 2 years of life

Question 56

pure capsular vaccine

Answer 56

Ineffective before 2 years, shorter immunity, no memory t cells

Question 57

conjugate vaccine

Answer 57

effective at all ages, longer immunity, recruits t cell memory

Question 58

infection from capsulated organisms indicate

Answer 58

decreased antibodies decreased complement no spleen