20 Into to Host Microbe Interactions

Question 1

3 ways microbes interact with host

Answer 1

commensalism, mutualism, parasitism

Question 2

what is commensalism?

Answer 2

microbes benefit from human but human is unaffected

Question 3

where do you not find normal flora in body?

Answer 3

internal tissues and organs, and fluids in these organs

Question 4

when microbe becomes established and begins grow on external body surface

Answer 4

colonization

Question 5

when microbe penetrates body surface, enters and multiplies in tissue, trigger immune response

Answer 5

infection

Question 6

an infection that results in damage to body

Answer 6

disease

Question 7

types of norm flora?

Answer 7

transient (hours–>days) and resident (long term, stable)

Question 8

_____ flora established in a few hours, ____ flora in 1-2 days

Answer 8

oral/nasopharyngeal, skin; GI

Question 9

site to site diffs

Answer 9

types and amounts of nutr, pH, O2 concentration, presence/absence antimicrobes, kinds of other microbes (competition)

Question 10

person to person diffs

Answer 10

age, sex, diet, hygiene, living conditions, other diseases

Question 11

skin flora?

Answer 11

less species diversity, transient in exposed surfaces, resident in protected areas (pores), mostly commensal

Question 12

mutualistic interaction in skin?

Answer 12

norm. flora metabolize lipids for nutr–>produce acidic waste which lowers pH and prevents pathogens from growing

Question 13

what is skin flora prob?

Answer 13

when take blood culture to test for bacteremia, collected by puncture in skin–>norm. flora in skin can contaminate blood cultures

Question 14

how to tell if microbe growing in blood culture true pathogen or just skin?

Answer 14

2 or 3 blood samples each from diff site

Question 15

species/numbers in mouth/tongue/teeth/saliva?

Answer 15

stre, haemophilus, Neisseria; biofilm communities (plaque, tongue), up to 10^7 per mL saliva

Question 16

species/numbers in nasal area/upper resp?

Answer 16

similar flora to mouth and skin, staph aureus found in 20% ppl

Question 17

lower resp tract species/#s?

Answer 17

no normal flora

Question 18

strepto mutans metabolizes ___ to produce _____

Answer 18

sucrose; dextran, glucose, fructose

Question 19

function of dextran?

Answer 19

sticky matrix

Question 20

functions of gluc and fruc?

Answer 20

further metabolized by other bacteria to give acidic waste products

Question 21

is urine in bladder sterile?

Answer 21

yess

Question 22

_____is transiently colonized by various species

Answer 22

first 1 cm of urethra

Question 23

how to diagnose UTI?

Answer 23

quantitative urine culture (not mid stream urine)

Question 24

many ___ found in large intestine, ____% are anaerobes/facultative anaerobes, ___% fecal mass is norm. flora

Answer 24

coliforms; 99; 25

Question 25

breast fed infants have > #s spp. metabolize :

Answer 25

lactose

Question 26

ex. mutualistic in intestinal tract?

Answer 26

get nutr from host, produce vits. for host

Question 27

artificial sweeteners appear to speed up development of ____

Answer 27

glucose intolerance

Question 28

how do bacteria salvage nrg and nut that would otherwise escape digestion?

Answer 28

bacteria convert CHO into SCFA–>inhibit pathogens, rapidly absorbed source of nrg

Question 29

potentially harmful activities of microbiota?

Answer 29

break down into carcinogens, release metabolic wastes that irritate mucosa

Question 30

what is priming of IS?

Answer 30

early age exposure of IS to microbes to ensure it can respond properly to pathogens

Question 31

removing normal flora w/ long time antibiotic use results in:

Answer 31

superinfection (resistant bacteria overgrowth)

Question 32

how to treat c. difficile colitis?

Answer 32

fecal microbiota transplantation (implant via enema or nasogastric tube)

Question 33

fecal transplantation also also used for:

Answer 33

IBS, enterocolitis, IBD

Question 34

microbe which is not pathogenic under normal conditions but may cause disease if introduced into normally sterile body site or host immunocompromised

Answer 34

opportunistic pathogen

Question 35

most common probio?

Answer 35

lactobacillus and bifidobacteria (gram pos., produce lactic acid)

Question 36

ex. of prebiotic?

Answer 36

fructo-oligosacc

Question 37

how probio work?

Answer 37

comp. exclusion of pathogens, stim mucus production and strengthen intestinal epithelial barrier, interactions w/ human immune sys (stim production of some immunoglob)