A new study shows that babies that are breastfed for at least six months have less antibiotic-resistant bacteria in their gut compared with infants breastfed for a shorter time. In addition, antibiotic use by mothers increases the number of antibiotic-resistant bacteria in infants.
Bacteria resistant to antibiotics are everywhere. They are present in the human gut, regardless of whether a person has taken antibiotics. They are transmitted between individuals in the same way as bacteria, viruses and other micro-organisms usually are: through, for example, direct contact and in food.
A recent study completed at the University of Helsinki investigated the amount and quality of bacteria resistant to antibiotics in breast milk and the gut of mother-infant pairs, resulting in three findings.
First, infants who were breastfed for at least six months had a smaller number of resistant bacteria in their gut than babies who were breastfed for a shorter period or not at all. In other words, breastfeeding seemed to protect infants from such bacteria.
Second, antibiotic treatment of mothers during delivery increased the amount of antibiotic-resistant bacteria in the infant gut. This effect was still noticeable six months after delivery and the treatment.
The third finding, meanwhile, was that breast milk also contains bacteria resistant to antibiotics, and that the mother is likely to pass these bacteria on to the child through milk. Nevertheless, breastfeeding reduced the number of resistant bacteria in the infant gut, an indication of the benefits of breastfeeding for infants.