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Scientists have found that sugars in breast milk kill bacteria that are resistant to antibiotics. They say that the sugars can help protect against drug-resistant superbugs. The sugars could be used in place of antibiotics to fight against antimicrobial resistance.

A group of bacteria known as group B Streptococcus (GBS) is a common cause of blood infections, meningitis, and stillbirth in newborns. An expectant mother who tests positive for GBS is usually given intravenous antibiotics during labor to help prevent early-onset infections during the first week of life. According to the U.S. Centers for Disease Control and Prevention, about 2,000 babies in the U.S. get GBS each year, and 4-6% of them die from it. In addition, the bacteria are often transferred from mother to baby during labor and delivery. Although GBS infections can often be treated or prevented with antibiotics, the bacteria are becoming alarmingly more resistant. 

The researchers isolated the sugars, called human milk oligosaccharides (HMOs), from the milk of several mothers before testing it on human cells infected with group B Streptococcus (GBS).

The findings presented at the American Chemical Society fall conference found that breast milk sugars could kill off bacterial infections in human tissues in the laboratory.

The sugars were also tested on pregnant mice. They were found to stop the spread of infection. The findings add to evidence of the importance of breast milk in protecting babies from infection and sickness and suggest that breast milk could be used to develop drugs.

Lead author Rebecca Moore, a graduate student at Vanderbilt University in Nashville, said, “Our lab has previously shown that mixtures of HMOs isolated from the milk of several different donor mothers have antimicrobial and antibiofilm activity against GBS. We wanted to jump from these in vitro studies to see whether HMOs could prevent infections in cells and tissues from a pregnant woman and in pregnant mice. In five different parts of the reproductive tract [in mice], we saw significantly decreased infection with HMO treatment.”

Co-author Professor Steven Townsend said, “HMOs have been around as long as humans have, and bacteria have not figured them out. Presumably, that is because there are so many in milk, and they are constantly changing during a baby’s development. But if we could learn more about how they work, it is possible we could treat different types of infections with mixtures of HMOs, and maybe one day this could be a substitute for antibiotics in adults, as well as babies.”

The researchers believe the sugars in breast milk can help prevent bacteria from ‘sticking’ to tissue surfaces. The sugars also act as a prebiotic by supporting the growth of good bacteria that can fight off harmful bacteria. The U.S. team now plans to identify the most useful sugars in breast milk – there are more than 200 types.

The bottom line is two fold:
1) Breast is best.
2) Hopefully someday soon, HMOs might be able to replace antibiotics for treating infections in infants and adults.