GI Pathogens

Question 1

colonisation

Answer 1

establishment of microorganisms within host - beneficial indigenous microbiota present in GI tract from birth

Question 2

ecological niches of bacteria in GI tract

Answer 2

oral cavity
pharynx
small bowel
large bowel

Question 3

normal flora/mirobiome of GI tract - oral cavity

Answer 3

viridans strep
anaerobic gram positive/negative bacilli
candida spp.

Question 4

principles of identifying gram negative rods

Answer 4

does the enterobacteriaceae ferment carbohydrate (lactose)

Question 5

gram positive organisms in GI tract - mouth

Answer 5

aerobic;
strep viridans
candida sp

Question 6

molecular tests

Answer 6

determines biochemical and antigenic characterises

e.g. MALDI-TOF mass spectrometry

Question 7

principles of serotyping

Answer 7

immunoreactivity of various antigens

Question 8

normal flora/mirobiome of GI tract - large bowel

Answer 8

enterobacteriaceae
enterococci
miller group strep
anaerobic gram postive/negative bacilli

Question 9

what bug do phagocytes respond to

Answer 9

bacteria

fungi

Question 10

what bug do T lymphocytes respond to

Answer 10

viruses
fungi
protozoa

Question 11

what bug do antibody and B lymphocytes respond to

Answer 11

viruses

Question 12

what bug do eosinophils respond to

Answer 12

fungi
protozoa
worms

Question 13

what bugs do mast cells respond to

Answer 13

worms

Question 14

what bugs do complement cells respond to

Answer 14

bacteria

Question 15

describe MALDI-TOF mass spectrometry

Answer 15

analyses protein composition of bacterial cell wall

discriminates between highly genetically similar organisms with identical rRNA

Question 16

tests for identifying enterobacteriaceae

Answer 16

MacConkey agar - pink if lactose present
CLED agar
chromogenic agar

Question 17

describe enterobacteriaceae

Answer 17

gram negative - endotoxin 
non spore forming 
fermet sugar 
anaerobic 
motile or non-motile 
increasing resistance

Question 18

gram postive organisms of GI tract - small bowel

Answer 18

anaerobic;

coliforms

Question 19

gram postive organisms of GI tract - colon

Answer 19

anaerobic;
colifros
enterococcus faecalis

Question 20

organisms of bile ducts

Answer 20

sterile