The mom’s microbiological present

During the gestation, the mothers bring all that necessary for thecorrect development of the baby. Did you know that also implies to microorganisms? For the good maturation of our intestines and immune system, we  need a contribution microbiological from mom. Enter and discover the different bacterial species  that gives us our mother in our first days of life.

STERILE PREGNACY?

For a long time it was believed that the uterus and amniotic sac that containing the fetus are a sterile place without any microbiological presence. Moreover, the mere presence of microorganisms was associated with a disease or a risk to the baby. So, it was believed that the fetus was conducted in a completely sterile environment during 40 weeks of gestation and came into first contact with some type of bacteria during birth.

Today, thanks to technological advances and genetic studies, it has been observed that this dogma was not true. Fetuses are in contact with bacteria throughout gestation. Generally it is non-pathogenic bacteria that are transmitted by the mother during pregnancy and after delivery.

Ultrasound of the placenta. In red are the bacterial communities, while in blue are observed them veins. (Image of Wolfgang Moroder)

This maternal microbiological transmission is a widespread phenomenon in many groups of the animal kingdom, such as Porifera, mollusks, arthropods and chordates. The presence of this phenomenon throughout the animal kingdom and the ease with which these organisms to reach the fetus, show that this transmission is a very old process and represents an evolutionary advantage to organisms.

Different organisms that maternal transmission has been observed. A) Pea Aphid (Acyrothosiphon pisum). b) Common chicken (Gallus gallus domesticus). c) Red Salmon (Oncorhynchus nerka) and d) River turtle Podocnemis expansa. (Image: Lisa Funkhouser).

TRANSMISSION ROUTES

There are different ways why does the mother get the baby the first bacterial communities. So the baby’s contact with his future microbiome is given for the first time through bacteria of the placenta. Then and during the delivery, some bacterial strains are transferred through the birth canal, skin and finally, through breast milk.

The differents transmission routes of microbiological communities. (Image: Lisa Funkhouser)

MICROBIOME OF THE PLACENTA

Is relatively recently,  that the presence of bacterial communities in this organ is known. Yet it is noteworthy that it is a small microbiome in terms of abundance. Generally, it is non-pathogenic microorganisms, but their variation could be related to common disorders in pregnancy such as premature births.

Initially it was believed that these bacterial communities would be related to the vaginal microbiota of the mother, but it has been observed that placental bacteria are more similar to those of the mother oral microbiota. According to research, the bacteria come from the mouth of the mother to the fetus through the bloodstream. So good oral health is essential for the proper development of the baby.

In the following diagram represent the main bacterial species identified in the human placenta. 

The major bacterial phyla observed in the placenta. Own image.

TRANSMISSION DURING CHILDBIRTH

As it is well known, during labor, a major transfer of bacteria occurs. Most of these bacteria are related to the vaginal and fecal microbiota of progenitor. During pregnancy, the vaginal microbiome of the mother varies and becomes less diverse, being more predominant the presence of bacteria such as Lactobacillus sp.

Still, it is noteworthy that this transmission will vary depending on the type of delivery, that is, babies born vaginally present similar microbiome to that of the vagina of the mother microbiota (Very rich in Lactobacillus sp., Prevotella sp., Bacteroides and Bifidobacterium sp.), while those born by Caesarean section present a more similar microbiome to the microbiota of breast skin, rich in Clostridium sp., Staphylococcus sp., Propionibacterium sp. and Corynebacterium sp.

The first baby’s microbiome depends on the type of chilbirth. In this diagram we can observe the differents bacterial communities that are involved in each one. (Own image)

SKIN CONTACT

As in other cases, skin with skin contact produces a transmission of microorganisms between two humans. In this case, it can be through the type of delivery (C-section), by contact with the external vulvar area of mother and by contact with the outer skin of his mother.

Some of the bacteria that are acquired at birth and are commonly in the skin of adult humans are Staphylococcus sp. Corynebacterium sp. and Propionibacterium sp.

MILK WITH BACTERIA

Another of the myths about esteril pregnancy was breast milk. Until recently it was thought that breast milk was sterile and bacteria that were in the samples were due to cross-contamination through the skin of the mother and the baby’s mouth. Today, thanks to the discovery of certain anaerobic bacteria, has concluded that the mother also provides certain bacterial communities by human milk.

There are a variety of microorganisms in milk and generally vary depending on the type of feeding and origin of the mother (See the different abundances of microorganisms in different mothers in the figure below). Still, it has been observed that during the early months of breastfeeding, breast milk is rich in Staphylococcus sp., Streptococcus sp. and Lactococcus sp.; while from six months of lactation milk is rich in typical microorganisms of the oral microbiota as Veillonella sp., Leptotrichia sp. and Prevotella sp.

Differences in the abundance of the bacterial species found in the breast milk of 16 analyzed subjects. (Image: Katherin Hunt)

Thus, it is expected that breastfed infants present a different intestinal and fecal microbiota than the artificialfed babys. These bacteria favor the baby against diarrhea, respiratory diseases and reduce the risk of obesity. BE CAREFULL! This does not mean that a child fed with artificial milk is worse than a breastfed, as many of these bacteria also can be purchased by other means.

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All these bacterial transmissions by the mother let the baby start the maturation of their immune system and the development of good intestinal microbiota. Our mothers always give it best to us!

REFERENCES

• Hunt, Katherin. Characterization of the diversity and temporal stability of bacterial Communities in human milk. (Article in English)

• Grens, Kerry. The maternal Microbiome. (Article in English)

• Funkhouser, Lisa. Mom knows best: the universality of maternal microbial transmission. (Article in English)

• Cover image: Joanna Noguera Riobueno.

Home’s micro-squatters

If you ever thought to be alone in your house, you were wrong. In your home there are thousands and thousands of micro-organisms sprout at ease. They are responsible for odors and pollution from yourhome. Would you like to know more about your tenants?

MICRO-SQUATTERS OF OUR HOUSES

It is stimated that about 90% if our time is spended in closed places, such as office, school or home. These places, as well as the rest of our planet, presents a environmental conditions suitable for proliferation of bacteria, fungi and arthropods. These communities are known as the Home’s Microbiome.

Photomicrograph of the bristle of a used toothbrush where proliferate a lot of microbial communities (Image: Science photo library)

The relations that we stablish with these communities of microorganisms can condition directly in our health. Can find beneficial microorganisms, indifferent microorganisms (i.e that do not produce any effect) and pathogenic microorganism (as Staphylococcus auereus resistant to antibiotics) or allergens as them mites. These pathogens, in most of cases, just represent a litle percentage and not pose any risk for them home’s occupants.

BACTERIA

Bacterial communities are very abundant in our homes. We can find them in every corner and have a great diversity. For example, in the dust is estimated that there are som 7000 different bacterial species. In the following graphic, can observe the broad diversity of bacterial species that colonizes certain regions of our home, such as the toilet’s lid, kitchen or our own beds.

Differents bacterial families that we can found arround our home (Image: G.E. Flores)

FUNGI

In normal conditions, a house can present up to 2000 different types from fungi. We can also find them in all home environment such as food, kitchen, walls and even in forgotten places during cleaning as for example the dust accumulated on the door frames. Among them, we can highlight the presence of Aspergillus, Penicillium and Fusarium (common envirnmental fungi). Also proliferate fungi responsible of the wood degradation (as for example Stereum, Tremetes, or Tremellosa) or fungi related with humans, like Candida.

Wall mold that appear in homes (Image: Mycleaningproduct.com) or fruit mold by Penicillium sp. (image: wisegeek).

MITES

These microorganisms represents to the Arthropods of our homes. Normally they live in dust, on rough surfaces such as fabrics, mattresses and pillowsa where they feed on died human and animals skin. We can find Dermatophagoides pteronyssus and Dermatophagoides farinae species, commonly knwon as dust mites. Even so, and to a lesser extent, we can find also some that another exemplay of Demodex folliculorum. This mite live in the hair follicles of our face and feeds on dead skin. Normally follows from the skin while we are sleeping.

Dust mite D. pteronyssinus (image: Göran Malmberg) and follicles mite Demodex folliculorum (Image: BBC)

BIOGEOGRAPHY AND  EMISSION SOURCES

The geographical distribution of these microscopic communities and those factors that determine it, are little known. For that reason, along this decade, studies about hom’s microbiome have increased and proliferated singnicantly.

The large microbial diversity changes over different locations in our home, i.e. we will not find the same microorganisms in bed than in the bowl of the toilet. For example, in our kitchen, depending on the place that we examine, we find greater abundance of specific bacterium or other. In the image bottom, us show as in the stove of our kitchen find more Salmonella sp than Clostridium sp.

Differences in the abundance of bacteria depending on the location (Image: G.E. Flores)

Even so, we can found a certain pater in this distribution, i.e. the microorganisms that inhabit certain areas are more similar than the comminities that we found in other locations. In the following dendogram we can observe that microorganisms found in our pillowcase are very similar to those that found in toilet, but completely different from whichwe can find in our kitchen cutting board.

Dendrogram of similarity between the bacterial communities of various areas of our home. (Image: Robert, D. Dunn).

But, what is the reason for this geographical distribution?

The response is found in the differents emission sources of these organisms. Depending on the source we can find find a few species or others. Obviously the main microorganism source of emission  into the environment are humans. We know that millions of bacteria and other microorganisms live in our body and they spread everywhere, either by respiratory activity, waste digestion or skin contact. Each human leaves a specific microbial fingerprint in those places. 

Major sources of emissions according to the area of the home to examine. See is that the largest source of emission are the own human. (Image: G. E. Flores)

In the graphic you can see that in some places appear microorganisms related to our intestines, specifically those who are ejecting with droppings. Is not wash you hans after going to the service, surely yo go spreading faecal bacteria everywhere. Also, if you pull the string with the toiled lid open, it causes the expansion of faecal bacteria as if it were a spray, reaching our toothbrushes  or the hand soap.

On the other hand, microbial diversity is very influenced by the number and type of home occupants. We cannot found the same microorganisms in a house with two persons than in other one with a family of seven. In addition, is has observed that not found the same microorganisms in homes where there is greater number of women that in which there is greater numer of males. Usually, mens released more microorganisms to environment.

Graphic of the influence of the genre of the occupants in the diversity of microorganisms in our home (Image: Albert barberán).

Another important factor that determines this geographical distribution and microbial diversity is the presence of pets. If in our homes we have animals like cats or dogs, we will found more varied microbial communities. In these case, these microorganisms are related to feces, skin and glans of these animals.

Differences in the abundance of certain bacterial species based on the presence or absence of pets (Image: Albert barberán).

Although the main source of emission are the occupants of these homes, microscopic comminities that colonise all corners are closely related to which we can found on the outside. In the case of fungi, this relationship is more narrow that in the case of bacteria. Even so, it has been observed that species are more varied in houses.

Comparison of the rich bacterial and fungal of our homes and the foreign. (Image: Albert barberán)

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How much reason have the phrase “as my home any place! Each home is indeed aunique and specific universe of microscopic communities. There aren’t two equal in the world!

REFERENCES

• Robert, D. Dunn. Home life: Factors Structuring the bacterial diversity found within and between homes.
• Albert Barberán. The ecology of microscopic life in household dust.
• Gilberto E. Flores. Microbial biogeography of public restroom surfaces.
• Cover Photo: Microbe.net