LG5.3 normal microbiota

Question 1

Define normal microbiota (normal flora). What determines your normal microbiota?

Answer 1

• found on body of healthy people
• begin colonization shortly after birth - normal flora mimics people that live around you and is also dependent on age, diet, hormones, health, hygiene

Question 2

commensalism

Answer 2

one member benefits while the other is unaffected

Question 3

mutualism

Answer 3

both members benefit

Question 4

define opportunistic pathogens (opportunists)

Answer 4

don’t produce disease in their normal environment, but can cause disease when introduced into unprotected sites, or when overgrow their normal environment (these cause MOST human infections)

Question 5

Differentiate colonization and infection

Answer 5

infection includes evidence of a pathological process in host. colonization doesn’t

Question 6

Recognize 22 sterile body sites, fluid

Answer 6

urine, urethra, ureters (proximal end), bladder, fallopian tube, vagina, cervix, blood, CSF, synovial fluid, amniotic fluid, internal eye, pancreas, deep tissues, brain, middle and inner ear, sinuses, larynx, trachea, esophagus, bronchioles, lower airways.

Question 7

List some roles of normal flora

Answer 7

1. end-stages food digestion
2. provide some vitamins (K)
3. contributes to immune system maturation and response
   
   • • competes with pathogens by using up space, nutrients, oxygen. also produce bacteriotocins

Question 8

Define ‘dysbiosis’

Answer 8

when microbes balance shifts in unhealthful direction.

Question 9

Describe one example of dysbiosis: CDAD

Answer 9

exogenous factors like acid neutralizers, antibiotic treatment disrupt microbiota balance and cause disease.

Question 10

Staphylococcus epidermidis

Answer 10

skin

hardy, relatively resistant to desiccation, salt acid

Question 11

Propionibacterium acnes

Answer 11

hair follicles, sebaceous glands

produces propionic acid which contributes to stinky feet

Question 12

Clostridium difficile

Answer 12

colon

2 - 10% healthy adults colonized, 20 - 50% hospitalized adults colonized; forms endospores

Question 13

Lactobacillus

Answer 13

vagina

major protection against vaginosis

Question 14

Escherichia coli

Answer 14

colon

member of the Enterobacteriaceae, synthesizes vit K

Question 15

Streptococcus mutans

Answer 15

mouth

produces acids that demineralize enamel

Question 16

Streptococcus pneumonia

Answer 16

nasopharynx

5-40% population colonized at this site; known for its capsule

Question 17

Staphylococcus aureus

Answer 17

nose

~30% population colonized at this site; hardy, relatively resistant to desiccation, salt, acid; produces many toxins

Question 18

Bacteroides

Answer 18

colon

dominant genus in this site; grown stimulated by bile

Question 19

Candida albicans

Answer 19

vagina

budding yeast; overgrowth with oral antibiotics

Question 20

Helicobacter pylori

Answer 20

stomach

makes its environment hospitable by raising the pH