Bacteria in the human body: when we die and when we are born

In summary, it is believed that around 90% of the cells in a human body are symbiotic bacteria. When we die, these bacteria may also die. However, some of these bacteria may survive without a human host and find a new home in another animal. It is unknown how many bacteria are transmitted to a person during their life, but most of the food we eat and water we drink is far from being sterile and only a few microbiota found in food are potentially hazardous.
  • #1
Gerinski
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It is said that around 90% of the cells in a human body are symbiotic bacteria living thanks to us.
When we die, do most of them also die? Or do they manage to survive without us and find a new 'home human'?

And opposite, when and how do we get all those bacteria after conception? Do we get some already from the mother while embryos in the womb? If so when do they start to 'invade' our body? Or do we get them only after birth and by which mechanisms?
 
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  • #2
I doubt it's as much as 90% of the human body mass, though micro organisms do exist in large quantities in the digestive tract and help in breaking down food into substances that can be easily absorbed.
I guess the original population probably does come from the mother, but after birth more will be added later when consuming food.
Most of the food we eat and water we drink is far from being sterile and only a few microbiota found in food are potentially hazardous.
 
  • #3
The 90% figure refers to the fraction of cells in your body that are bacterial, not the mass.
 
  • #4
Pythagorean said:
The 90% figure refers to the fraction of cells in your body that are bacterial, not the mass.
Indeed, thanks
 
  • #5
It is an interesting question. Presumably if bacteria and other components of the biome could evolve a way to get into a new animal at death than it would be very much to their advantage.

My suspicion is that one way is they might transform into some kind of dormant mode capable of surviving in soil until ingested by another animal... a bit like the way prion diseases propagate.
Alternatively, they might hope to survive in water courses.

If they need to harden themselves for the transition then do they have some kind of quorum sensing mechanism to detect when death occurs? Perhaps even cause death?
Maybe something to consider when reading about the 'death wave':
http://www.scientificamerican.com/article/blue-death-in-worms/

But there are known ways that they are transmitted - I understand a main one is during birth - one of the unknowns about birth by caesarean section is how much of a disadvantage it is not to get so much of the mother's biome.
 
  • #6
Gerinski said:
<snip>And opposite, when and how do we get all those bacteria after conception? Do we get some already from the mother while embryos in the womb? If so when do they start to 'invade' our body? Or do we get them only after birth and by which mechanisms?

Our gut becomes colonized by bacteria by eating- newborns do not have gut bacteria, this is one of the reasons why their diet is so different (early immunity comes from mother's milk). There is a discussion about the differences in gut bacteria between 'natural' and delivery by Ceasarean, but I don't know the current state of knowledge. I don't know how long it takes for bacteria to colonize, but it's reasonably short- weeks. Also, for many animals, an early meal is fecal matter- that is a very efficient way to get bacteria into the gut.
 
  • #7
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Likes 256bits, Andy Resnick and jim mcnamara

Related to Bacteria in the human body: when we die and when we are born

1. What types of bacteria are found in the human body?

There are thousands of different types of bacteria that can be found in the human body. Some of the most common species include Staphylococcus, Streptococcus, Escherichia coli, and Bacteroides.

2. How does bacteria in the body affect our health?

Bacteria in the body can have both positive and negative effects on our health. Some bacteria, known as probiotics, help with digestion and boost our immune system. However, harmful bacteria can cause infections and diseases if they are not kept in check by our immune system.

3. Does the amount of bacteria in our body change throughout our lifetime?

Yes, the amount of bacteria in our body changes as we age. Babies are born with relatively few bacteria in their bodies, but they are quickly colonized by bacteria from their environment. As we grow older, the types and amounts of bacteria in our bodies may change due to factors such as diet, hygiene, and exposure to different environments.

4. What happens to bacteria in the body when we die?

When we die, our body stops producing the enzymes and chemicals that help keep bacteria in check. As a result, bacteria that are normally present in our body can multiply and spread, leading to decomposition. This process is a natural part of the decomposition process and helps to break down our body tissues.

5. Can bacteria in the body be passed from a mother to her child during birth?

Yes, bacteria can be passed from a mother to her child during birth. This is known as the "bacterial inheritance" and can have a significant impact on the child's microbiome (community of microorganisms in the body). The types of bacteria passed on from the mother can affect the child's immune system and overall health.

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