Standard Practice of Giving Premature Babies Antibiotics Needs to be Rethought, Argues New Study

A doctor touches the feet of a premature baby lying in a toweling nest inside an incubator. A new study finds preemies' gut bacteria often includes close relatives of the microbes that can cause hospital-acquired infections. REUTERS/Claudia Daut

When all preemies are born, physicians administer certain antibiotics since their tiny immune systems are even less well equipped than healthy babies to fight off infections. But it turns out this comes with serious risks.

A study published March 7 in Nature Microbiology finds premature infants in hospitals have gut bacteria with extensive antibiotic resistance. This is a result of standard medical treatment in neonatal intensive care units, which is to administer prophylactic antibiotics beginning the first few days of life.

For the study, researchers at Washington University School of Medicine in St. Louis analyzed 401 stool samples from 84 preterm infants over the first three months of life. They conducted DNA sequencing on all of the bacteria from the samples, and identified nearly 800 genes in these bacteria related to antibiotic resistance. The researchers compared the results on babies at three months versus preemies that were just a few days old, and found babies that received antibiotics for longer had less diverse gut bacteria and more that were potentially harmful.

"The scary part of our study was the fact that when we looked at which bacteria are in the kids' guts, they are very close to the bacteria in hospitals that cause infection," says lead author Gautam Dantas, associate professor of pathology and immunology at Washington University School of Medicine. "These kids are being colonized by close relatives of really bad bacteria."

The researchers identified genes that suggest bacterial resistant to 16 different antibiotics. Some of the genetic components of the bacteria are close relatives to a number of pathogens that could potentially be antibiotic-resistant, such as Escherichia coli (E. coli ), Klebsiella and Enterobacter. Some bacteria sequenced from the samples had resistances to multiple antibiotics, including "last resort" treatments like meropenem.

The researchers also compared the microbiomes of preterm infants to full-term babies. They found the preemies had tenfold less bacterial diversity than babies born at complete gestation. Because antibiotics effectively wipe out the human gut, this standard treatment also kills good bacteria—the kind that keeps an infant healthy.

Other research suggests microbiome diversity is critical to human health; the less variation, the higher the likelihood is that these "bad" bugs will overcolonize. The bugs that live inside a person influence health in a number of ways, including risk for certain diseases, nutrition and immune function. This is especially the case for infants, and the researchers say it's of high concern that the microbes they identified are more harmful than helpful.

While it's customary for all premature infants to receive antibiotics, the study suggests hospitals should do so more prudently. "Neonatologists are under pressure from parents," says Dantas. "It's hard for a doctor to say, 'No, I'm not because there might be collateral damage.'" Dantas says the best solution is to work on improving technologies that safeguard babies, like rapid DNA sequencing that will allow health care providers to determine when exposure is potentially dangerous.

Additionally, Dantas recommends that researchers consider a new approach to developing antibiotics that are safe and effective for the littlest patients. Rather than kill the bacteria outright, he suggests a new class of drugs should function by stopping these microbes from emitting the toxins that lead to a serious and life-threatening infection, which means the good bugs would also survive.