- The vertical
transmission of microbiome from mother to child was studied using shotgun
- It was found that
infants shared same strains of bacteria with their mothers, confirming
vertical transmission of microbes.
- One infant
had Bifidobacterium bifidum strain which was 99.96% identical with
the strain present in the mother.
birth of a baby via normal delivery leads to the colonization of microbes
during birth and moments soon after delivery which is known as the vertical
transmission of microbes. The evidence of this type of transmission has been
limited but a new study has combined laboratory evidence with novel
computational techniques to identify the vertical transmission of microbes.
Evidence of Transmission
were several bacterial strains that were identical, both in the mother as well
as in infants which were distinct when compared to the microbes found in other
mothers or infants. This was strong evidence in support of vertical
‘Gut microflora transmitted from mother to child will aid in healthy microbiome. Novel technology identifies vertical transmission of microbes.’
from this evidence, the research team from Italy that conducted the study found
that, Bifidobacterium and Bacteroids strains were found in the infant gut as
well as the gut of mothers.
Important for a Healthy Microbiome
professor at the Centre for Integrative Biology, Dr. Nicola Segata who is the
senior author of the study said that early exposure of infants to gut
microbiome was vital for the acquisition and
a healthy microbiome. The research team under Dr. Nicola devised methods
that identified the vertical transmission of microorganisms from mothers to
their infants, showing that mothers were sources of microbes which were vital
for the development of healthy infant gut
that were conducted earlier showed that the species of microbes were the same
in both the mothers as well as infants but as these studies were cultivation
free, the exact strain of the microbes could not be ascertained. Dr. Adrian
Tett who was the co-senior author of the study concluded that unless the
microbes were found to be the same strain or the same genetic variant, it would
be difficult to ascertain if they were obtained through vertical transmission.
Infant Gut or the Womb?
exact stage at which colonization of microbes occurs has been the topic of
debate among scientists, whether it occurs in the infant's gut at the time of
birth or if it occurs in the womb. Dr. Segata said that if it could be found
that exposure to microbiome occurs at the time of delivery then if the
mother harbors an infectious strain which could harm the baby, then preventive
medicine could be prescribed to avoid transmission to the infant.
medical practices advocate the use of tests to detect Streptococcus
group B strains and preventive medication is
administered to avoid the transmission to the new born infant.
Identifying Vertical Transmission
study included 5 mother and baby pairs who were recruited from a hospital when
the infants were three months old. Fecal and breast milk samples were
collected. Additional samples were collected from two of the mother- infant
pairs when the infants were about 10-months-old and from another pair when the infant was about 16-months-old.
24 samples that consisted of 8 breast milk, 8 mother fecal and 8 infant fecal
samples were analyzed using shotgun metagenomics sequencing. An additional tool
called metatranscriptomics was also utilized to identify which microbes were
present in two of the pairs of the fecal samples.
study found that
- The intestines of
the mothers showed greater microbial diversity, which was expected.
- The gut
microbiome analysis of the 16-month-old infants showed that the diversity
of the gut microbiome was by now more like the mother.
- Samples of breast
milk showed limited diversity when they were collected soon after birth.
- Microbes that are
normally found in the skin were found only in small numbers in the gut of
infants showing that skin microbes do not normally colonize in the gut of
Analyzing Microbial Transmission
The metagenomic samples were further
analyzed to understand the strains of bacteria that were present using
computational techniques that were newly developed. The results of this part of the study were:
- One infant
carried Bifidobacterium bifidum
strain which was 99.96% identical to the mother's strain but which was
different from the strains found in the other infants.
- Ruminococcus bromii
and Coprococcus were found in
another infant and which was over 99% identical with the mother's.
aided in identifying that the same strains of bacteria
were found in both the mother and the child, providing strong evidence about
are further studies that are planned by the research team to understand the
significance of mother to infant transmission and comparing this with vaginal
and cesarean delivery, skin contact and breast feeding routes of transmission.
Advantages of the Microbiome in Humans
are numerous microorganisms in the body and it is estimated that the genes
present in these organisms are more than those in the human genome. The metabolic activities that are carried
out by the gut microflora have resulted in them being called a 'forgotten'
- Fermenting unused
harmful bacteria from colonizing
- Preparing the
- Regulating the
vitamins like vitamin K and biotin which can be utilized by the host
microbiome present in humans is very important, especially gut microbiome as
they play an important role in digestion. It is therefore important to study
the vertical transmission that occurs from the mother to child and to identify
methods to ensure a healthy gut microbiome.
current study that focuses on the presence of vertical transmission between
mother and child will aid in understanding the benefits of a normal delivery
and the healthy microbial environment which could be passed on.
- Cesarean versus Vaginal Delivery: Long term infant outcomes and the Hygiene Hypothesis - (https:www.ncbi.nlm.nih.gov/pmc/articles/PMC3110651/)