Breastfeeding women can dramatically lower the risk of antibiotic-resistance in their baby by adding a probiotic supplement to its diet, according to a new study.
Researchers say it provides a deadly combination for proteins that fuel the condition - destroying almost nine-in-10.
Infants nursed with mother's milk - and fed the 'friendly bacteria' Bifido infantis - had on average 87.5 per cent fewer antibiotic resistance genes in their gut microbiome.
This was compared with breastfed infants not given the powder which is mixed with water or soluble food.
It is the first time the gut bacteria of babies has been "significantly remodelled", a meeting of the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) in Geneva was told.
Antibiotic resistance is one the most serious global health threats. By 2050 10 million lives a year will be at risk from antibiotic-resistant infections, say experts.
Mothers are urged to breastfeed - if possible - in order to give their babies the best possible start in life.
The microbe B. infantis is boosted by breast milk - providing the food for it to flourish. It has been disappearing from the intestines of babies across the world - including Britain.
The increase in Caesarean sections and reduction in breastfeeding has been blamed.
The UK has one of the worst breastfeeding rates in the world. Just over a third (34 per cent) of babies are receiving any breast milk at six months - compared with nearly two-thirds (62.5 per cent) in Sweden.
B. infantis is passed from mother to baby during vaginal birth - and its importance to good health is being increasingly recognised.
In the study 38 genes linked to antibiotic-resistance were reduced in the supplemented infants.
These included ones associated with a wide range of drugs prescribed to treat respiratory, intestinal and urinary infections - as well as chlamydia and acne.
Antibiotic resistance has been identified by the World Health Organisation as one of the biggest threats to global health.
It has led to fears we may be returning to a time when the drugs - commonly given to children for a host of ailments - are no longer effective.
Lead author Dr Giorgio Casaburi said the rising prevalence of antibiotic-resistant genes in children is a growing public health concern.
Misuse of drugs in humans and animals is accelerating this threat.
Members of the public frequently use antibiotics when they are not required. It's estimated over half of all those taken are not actually needed.
They are often fed to livestock to boost food production. Resistance can spread when new generations inherit antibiotic resistance genes.
Dr Casaburi is a nbioinformatics scientist at microbiome company Evolve Biosystems Inc in Davis, California, which makes the probiotic B infantis EVCOO1 used in the study.
He said: "These results demonstrate targeted bacterial supplementation is capable of remodelling the ecology of the infant gut microbiome and therefore reduce antibiotic gene reservoirs in children.
"We found supplementation with the infant gut symbiont (an organism living in harmony with another) significantly diminished both the abundance and diversity of antibiotic resistance genes."
His team assessed 60 infants 29 of whom - along with exclusive breastfeeding - received the probiotic supplement mixed into the milk for 21 days.
After two weeks stool samples were collected and compared with babies who had only received breast milk.
This enabled the researchers to evaluate the presence of the antibiotic resistant proteins in both groups.
The probiotic utilised in the research is uniquely adapted to thrive in the infant gut and is often missing from the microbiome of infants born in Europe and the US today.
In the absence of this protective bacterium other bugs colonise the gut microbiome and enable the evolution, persistence and dissemination of antibiotic resistance genes.
Dr Casaburi said: "The supplementation offers a novel approach towards providing an alternative, safe and non-invasive method to decrease the number of genes that resist antibiotics in infants.
"This is the first demonstration of significant remodelling of the infant gut microbiome.
"This modulation could help to reduce the burden and diversity of antibiotic resistance genes in current and future generations."
The name B. infantis makes it clear it is important to healthy babies. It is often one of the first probiotics a mother will pass to her baby. Many doctors recommend pregnant women take the supplement.
After B. infantis colonises us as infants it lives in our bodies our whole life. Their primary job is to improve our digestion and to protect against infection and sickness.
It has also been shown to fight allergies - and even help prevent kidney stones.
B. infantis produces large amounts of acid to make our digestive tracts - and the vagina - inhospitable to foreign bacteria and parasites.