E4 Gut microbiology: the human microbiome Flashcards
(53 cards)
what is a microbiome?
the community of microorganisms that inhabit our bodies and coexist with us without causing harm
what are the 3 types of microorganisms in microbiomes?
commensal
symbiont
pathobiont
describe commensal microorganisms
microorganism that derives food / other benefits from another organism without hurting or helping it
describe symbiont microorganisms
microoganism that lives together in harmony with another organism, providing a benefits to one / both organisms
describe pathobiont microorganisms
microorganism that can cause disease in certain conditions (opportunistic pathogens) but not typically if healthy
what is understanding the microbial make up of a person important for?
for when considering how microbes influence human disease
state parts of the body that microbiomes are found in
nose
ear
conjunctiva
mouth
oesophagus
breastmilk
lungs
stomach
urinary tract
large intestine
small intestine
vagina
skin
state 2 of the many functions of microorganisms in the body
- protecting the body by establishing themselves as normal residents
- aiding in digestion and the maturation / development of our immune system (eg. some can digest fibre which humans cannot digest themselves
regarding bacteria, what happens to newborns within 12 hours of delivery?
they are colonised by many species of bacteria as well as fungi and protozoa
are babies in a sterile environment prior to birth?
- yes, the uterus
- unless, in utero infection is passed from mother via placenta
compare the differences in bacteria on babies delivered vaginally vs. caesarean
vaginal delivery
- babies covered in microbes as they pass through the birth canal (including bacteria that help babies digest their first meal)
- eg. Lactobacillus
caesarean
- babies colonised mainly by skin microbes of different species because they do not come through the birth canal
- eg. Staphylococci, Streptococci
describe the microbiomes of babies in the first 6 months of life
- within weeks, microbes start to specialise in different parts of the body that are suited for certain species
- further exposures mean microbes compete
- eating solids causes population changes of microbes
how does a baby starting solids cause changes in microbes?
- different microbes grow best on differs types of food and require different nutrients
- before solid foods, only bacteria that could thrive on milk would be highly prevalent
describe the microbes of breast-fed babies in their first 6 months of life
- acquire a wide spectrum of gut bacteria
- some species help metabolise sugars into acids that protect the baby from certain intestinal infections (helps nurture and strengthen immune system)
- will be exposed to increased bacteria due to mouth coming into contact with bacteria around mum’s nipple
describe the microbes of formula-fed babies in their first 6 months of life
- acquire mainly mix of Lactobacilli, Staphylococci, enteric Streptococci and coliforms
- some formula milk is fortified with probiotics (microbes) and prebiotics
- microbes in the air and atmosphere may end up in formula
- won’t be as many or as much variety as in breastfed babies
what happens to the species of microbes in children between 6 months and 3 years of age?
- continually increase in number
- approx 100 species of microbes in the gut of young infants
- by 3 years old, the microbiome looks a lot more like an adult’s, just on a smaller scale
why does the microbiome of 6 months - 3 years old children continually change?
several factors including:
- nutrition, infection, medications and environment
- microbiome variation is highest during childhood
other than age and environment, what else can influence our microbiome?
parents, family and relatives
- sharing of environments and other lifestyle factors
- influence of the mother is lessened over time and young children’s microbiomes come to resemble both parents
- as children get older and spend less time around their parents, their microbiome resembles their parents’ less
approximately how many species of microbes are present in our guts by the time we become adults?
approximately 1000
state a feature of adult microbiomes
more stable than child microbiomes
what is the adult microbiome affected by?
a range of factors
- biological factors
- environmental / external factors
what biological factors affect adult microbiomes?
age
hormones
genetics
what environmental / external factors affect adult microbiomes?
diet
drug therapy
climate
occupation
how does age affect the adult microbiome?
variation decreases following adulthood and after age 65, the number of microbial species decreases more rapidly
