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A new research reveals that mothers of preterm babies have highly individual breast milk microbiomes which can be affected by even short courses of antibiotics, in the long run.
Led by researchers from the University of Toronto and The Hospital for Sick Children, the study is the largest to date of breast milk microbiota in mothers of premature infants. It is the first to show how antibiotic class, timing and duration of exposure have specific effects on the most common microbes in breast milk. A lot of them are capable of influencing growth and immunity to disease in new-borns.
“It came as quite a shock to us that even one day of antibiotics was associated with profound changes in the microbiota of breast milk,” says Deborah O’Connor, a professor and chair of nutritional sciences at U of T and a senior associate scientist at SickKids. “I think the take-home is that while antibiotics are often an essential treatment for mothers of preterm infants, clinicians and patients should be judicious in their use.”
Most of the programs about antibiotic stewardship that take place in neonatal intensive care, lay emphasis on limiting the use in new-borns themselves. Published in the journal Cell Host and Microbe, this study presents growing evidence that these programs must include a focus on mothers as well.
The study takes a look at 490 breast milk samples from 86 mothers of preterm babies, during the first eight weeks post-delivery. As far as the findings are concerned, they found that the body mass index of the mother and the mode of delivery had an impact on the breast milk microbiota.
The effects of antibiotics in many cases even lasted for weeks. And the changes induced by the anti-biotics seemed to affect the key microbes known to play a role in fostering disease, or in gut health and metabolic processes that promote babies’ growth and development.
“Overall, we saw a decrease in metabolic pathways, and increase in more pathogenic pathways in bacteria over time,” says Michelle Asbury, a doctoral student in O’Connor’s lab and lead author on the paper. “Of particular concern was an association between antibiotics and a member of the Proteobacteria phylum called Pseudomonas. When elevated, Proteobacteria in a preterm infant’s gut can precede necrotizing enterocolitis.”
Around seven per cent of the preterm babies happen to develop necrotizing enterocolitis, a frequently fatal condition in which part of the bowel dies. Another thing that affects the overall diversity of breast milk microbiota is the class of antibiotics called cephalosporins.
According to Asbury, it is too early to know what the findings mean for preterm infant health and outcomes. She and her colleagues aim to dive into those questions in the upcoming year, as they compare their findings with stool samples from the preterm infants involved in the study. This should reveal whether changes in the mothers’ milk microbiomes are actually seeding the infants’ guts to promote health or increase disease risk.
Meanwhile, she emphasizes on the importance of antibiotic intake for mothers of preterm infants for some cases of mastitis, blood infections and early rupture of membranes. Around 60% of women in the current study took antibiotics and that highlights both the vast need for these drugs and the potential for some overuse.
Sharon Unger, a co-author on the study and a professor of paediatrics at U of T, as well as a scientist and neonatologist at Sinai Health and SickKids says that the benefits of breast feeding far outweigh the risk that antibiotics can disrupt the breast milk microbiome. She suggests that mothers should without a doubt continue to provide their own milk when possible.
“But I think we can look to narrow the spectrum of antibiotics we use and to shorten the duration when possible,” Unger says. She adds that advances in technology may allow for quicker diagnoses of infection and better antibiotic stewardship in the future.
Unger believes that the rapidly moving field of microbiome research holds great promise for preterm infants. “Clearly the microbiome is important for their metabolism, growth and immunity. But emerging evidence on the gut-brain axis and its potential to further improve neurodevelopment for these babies over the long term warps my mind,” she adds.
(With inputs from ANI)