GUT- Intro to Microbiology of the Gut Flashcards
what is a commensal organism
one that does not cause harm
what is normal flora
microbes present normally in a healthy individual
what is a pathogen
a disease causing microbe
what is an anaerobe
an organism with doesn’t require oxygen
what is acute diarrhoea
sudden onset of diarrhoea
what is chronic diarrhoea
long term diarrhoea
how many normal bacterial flora are found in the stomach and small intestine
only a small amount
what kinds of flora are found in the large bowel
anaerobes bacteroides coliforms E.coli Enterococci
what is the function of bifidobacterial
produce lactic aids, prevent the growth of gram negative bacteria, metabolise breast milk sugars
what is meant by dysbiosis
change in normal flora which could potentially cause harm
what happens to the microbiome when an obese person loses weight
it changes - can be managed by a faecal transplant (aid weight loss)
what are the host defences against infection from the normal flora
structural - seamless epithelium, tight junctions, high turnover
mechanical - peristalsis, chewing, fluid movement
biochemical - gastric acid, bile, mucous
immunological - secretory IgA, intra-epithelial lymphocytes
what are the benefits of gut flora
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
what are the uses of probiotics in medicine
control of diarrhoea in infants relieve constipation improve digestion of lactose restore normal gut flora improve the immune system treat IBD
why is microbial antagonism important
maintains flora through complex interactions competition limits growth reduces pH occupies all niches
why is a loss of flora detrimental
allows bacterial / pathogen overgrowth
how is a loss of flora treated
stopping antibiotics using other antibiotics antitoxins faecal microbiota transplant colectomy
differentiate between food poisoning and foodborne infection
foodborne infection - caused by consuming contaminated food / beverages
food poisoning - caused by consuming toxins cause by microorganisms in food
what are some pathological mechanisms for common GI infections
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
