gut microbiology

Question 1

how many species in normal flora

Answer 1

> 800

Question 2

difference between resident and transient flora

Answer 2

resident - for life

transient - temporarily carried, reduced, or changed

Question 3

types of symbiosis

Answer 3

commensalism, mutualism

Question 4

what does commensal mean

Answer 4

when TOGETHER the flora don’t cause any harm to the host

Question 5

why is the stomach sterile

Answer 5

too inhospitable for normal flora

Question 6

what microbe can cause gastric ulcers

Answer 6

helicobacter pylori

Question 7

what kind of bacteria exist in the large intestine

Answer 7

obligate and facultative anaerobes - bifidobacteria, enterobacteria etc.

Question 8

examples of diseases associated with microbiome alterations

Answer 8

crohn’s

IBS, ulcerative collitis

Question 9

intestinal properties affected by the microbiome

Answer 9

modulation of digestion and absorption - inc energy harvesting
host metabolism/energy homeostasis - endocrine function, inflammatory signals

Question 10

structural host defences

Answer 10

seamless epithelium, tight junctions - sloughing/turnover

Question 11

mechanical host defences

Answer 11

peristalsis
chewing
fluid movement

Question 12

biochemical host defences

Answer 12

gastric acid
bile
mucous

Question 13

immonological host defences

Answer 13

secretory IgA, intra-epithelial lymphocytes

Question 14

benefits of gut flora

Answer 14

colonisation resistance
metabolites of benefit to host
normal immunity development
aids digestion

Question 15

what do probiotic organisms do

Answer 15

produce lactic and organic acids

Question 16

what do prebiotics do

Answer 16

alter gut ecosystem, promote growth of probiotes

Question 17

uses of probiotics in medicine

Answer 17

control infant diarrhoea
relieve constipation
improve lactose digestion

Question 18

why is microbial antagonism good

Answer 18

maintains flora - competition, complex reactions - limits growth of competitors and pathogens

Question 19

what happens if flora is lost

Answer 19

bacterial or pathogen overgrowth

Question 20

what can cause loss of flora

Answer 20

drugs eg ciprofloxicin

Question 21

def of gastroenteritis

Answer 21

acute syndrome characterised by GI symptoms in any combination

Question 22

def of diarrhoea

Answer 22

frequent passage of loose, fluid, unformed stools

Question 23

clinical consequences of diarrhoea

Answer 23

can lead to severe dehydration
excessive fluid and electrolyte loss
hypovolaemia
hypokalaemia
long term morbidity and reduced growth

Question 24

def of dysentery

Answer 24

inflammatory disorder of the GI tract - usualy LI

Question 25

def of enterocolutis

Answer 25

inflammation involving mucosa of small and large intestine

Question 26

how are diarrhoeal diseases transmitted

Answer 26

shed in faeces - faecal - oral route

Question 27

what is the GI response to superficial microbial invasion

Answer 27

local inflammation

Question 28

what can cause perforation/ulceration of the mucosal epithelium

Answer 28

peritonitis/intra abdominal abscess

Question 29

mechanisms of diarrhoea

Answer 29

``` bacterial toxins - enterotoxins exotoxins cytotoxins adherence damage to epithelium penetration and invasion ```

Question 30

why is the infectious dose important

Answer 30

affects incubation time, severity of disease

Question 31

what is food poisoning

Answer 31

symptoms caused by preformed toxins in the food, often heat-stable

Question 32

what is food associated infection

Answer 32

infection with live organism that grows in the gut and causes symptoms