5.3 - Normal Microbiota

Question 1

Provide the unique role or specific adaptation for Lactobacillus

Answer 1

human niche in the vagina, major protection against vaginosis

Question 2

Provide the unique role or specific adaptation for Candida albicans

Answer 2

human niche in the vagina, budding yeast, overgrowth with oral antibiotics

Question 3

Provide the unique role or specific adaptation for Helicobacter pylori

Answer 3

Human niche in the stomach, makes its environment hospitable by raising the pH

Question 4

Provide the unique role or specific adaptation for Clostridium difficile

Answer 4

Human niche in the colon, 2-10% healthy adults colonized, 20-50% hospitalized adults colonized; forms endospores

Question 5

Provide the unique role or specific adaptation for Escherichia coli

Answer 5

Human niche in the colon, member of the Enterobacteriaceae; synthesizes vitamin K

Question 6

Provide the unique role or specific adaptation for Bacteroides

Answer 6

Human niche in the colon, dominant genus in this site; growth stimulated by bile

Question 7

Provide the unique role or specific adaptation for Propionibacterium acnes

Answer 7

Human niche in the hair follicles, sebaceous glands, produces propionic acid which contributes to stinky feet

Question 8

Provide the unique role or specific adaptation for Staphylococcus epidermidis

Answer 8

Human niche in the skin, hardy, relatively resistant to desiccation, salt and acid

Question 9

Provide the unique role or specific adaptation for streptococcus pneumoniae

Answer 9

human niche in the nasopharynx, 5-40% population colonized at this site; known for its capsule

Question 10

Provide the unique role or specific adaptation for staphylococcus aureus

Answer 10

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

Question 11

Provide the unique role or specific adaptation for Streptococcus mutans

Answer 11

Human niche is in the mouth, produces acid that demineralize enamel

Question 12

What is normal microbiota

Answer 12

microorganisms frequently found on or in the body of healthy people

Question 13

Commensalism

Answer 13

one member benefits while the other is relatively unaffected

Question 14

Mutualism

Answer 14

both members benefit

Question 15

Resident microbiota

Answer 15

is a type of colonization. Relatively fixed, washing, sweating doesn’t significantly alter, if disturbed, reestablishes

Question 16

Transient microbiota

Answer 16

type of colonization, from the environment, food and water, can be either non or pathogenic

Question 17

Pathogen

Answer 17

always associated with disease

Question 18

Opportunist

Answer 18

don’t produce disease in their normal environment, but can cause disease when introduced into unprotected sites, or when overgrow their normal environment

Question 19

Colonization

Answer 19

if the bacteria, fungi… are growing but there is no pathology associated with it

Question 20

Infection

Answer 20

if the bacteria, fungi… are growing but there is pathology associated with it

Question 21

What are normally sterile sites?

Answer 21

Amniotic fluid, blood, CSF, synovial fluid, deep tissues, organs, brain, sinuses, middle and inner ear, and internal eye.

If microbes are present it is usually diagnostically significant.

Question 22

What sites are normally sterile but can have transients?

Answer 22

Larynx, trachea, esophagus, bronchioles, lower airways.

Question 23

What are sites that are not sterile?

Answer 23

Hair follicles, stomach, upper respiratory tract, mouth, nose, pharynx, perineum, vagina, colon, and skin.

Question 24

What are the roles of normal microbiota?

Answer 24

• Participate in end stages of food digestion
• Provide some vitamins
• Help protect against pathogens
• Contribute to maturation of immune system
• Stimulate immune response
• Competition for binding sites, space
• Relatively constant unless exogenous factors like acid neutralization antibiotic treatment, which will disrupt balance.

Question 25

What is Dysbiosis?

Answer 25

Refers to microbial imbalance on or inside the body.

Question 26

What is CDAD?

Answer 26

Clostridium difficile-associated diarrhea

Question 27

How is CDAD a dysbiosis?

Answer 27

Antibiotic treatment kills normal flora and allows C. diff to bind and multiple as many strains are antibiotic resistant, they release toxin and cause diarrhea