GUT- Intro to Microbiology of the Gut

Question 1

what is a commensal organism

Answer 1

one that does not cause harm

Question 2

what is normal flora

Answer 2

microbes present normally in a healthy individual

Question 3

what is a pathogen

Answer 3

a disease causing microbe

Question 4

what is an anaerobe

Answer 4

an organism with doesn’t require oxygen

Question 5

what is acute diarrhoea

Answer 5

sudden onset of diarrhoea

Question 6

what is chronic diarrhoea

Answer 6

long term diarrhoea

Question 7

how many normal bacterial flora are found in the stomach and small intestine

Answer 7

only a small amount

Question 8

what kinds of flora are found in the large bowel

Answer 8

anaerobes
bacteroides
coliforms
E.coli
Enterococci

Question 9

what is the function of bifidobacterial

Answer 9

produce lactic aids, prevent the growth of gram negative bacteria, metabolise breast milk sugars

Question 10

what is meant by dysbiosis

Answer 10

change in normal flora which could potentially cause harm

Question 11

what happens to the microbiome when an obese person loses weight

Answer 11

it changes - can be managed by a faecal transplant (aid weight loss)

Question 12

what are the host defences against infection from the normal flora

Answer 12

structural - seamless epithelium, tight junctions, high turnover

mechanical - peristalsis, chewing, fluid movement

biochemical - gastric acid, bile, mucous

immunological - secretory IgA, intra-epithelial lymphocytes

Question 13

what are the benefits of gut flora

Answer 13

blocks pathogenic colonisation
some metabolites are of a benefit to the host - Vit K, B12, etc..
aids in the normal development of immunity
aids in digestion - fermentation of sugar

Question 14

what are the uses of probiotics in medicine

Answer 14

control of diarrhoea in infants
relieve constipation 
improve digestion of lactose
restore normal gut flora
improve the immune system
treat IBD

Question 15

why is microbial antagonism important

Answer 15

maintains flora through complex interactions
competition 
limits growth 
reduces pH
occupies all niches

Question 16

why is a loss of flora detrimental

Answer 16

allows bacterial / pathogen overgrowth

Question 17

how is a loss of flora treated

Answer 17

stopping antibiotics
using other antibiotics
antitoxins
faecal microbiota transplant
colectomy

Question 18

differentiate between food poisoning and foodborne infection

Answer 18

foodborne infection - caused by consuming contaminated food / beverages

food poisoning - caused by consuming toxins cause by microorganisms in food

Question 19

what are some pathological mechanisms for common GI infections

Answer 19

bacterial toxins - can either directly damage cells or affect fluid/ electrolyte transport by increasing or decreasing cAMP
adherence - cause damage to epithelium

penetration and invasion - disruption of tissue architecture and function
inflammation