Skip Routine Probiotics for Preemies, AAP Says

Diana Swift

May 25, 2021

The American Academy of Pediatrics (AAP) now recommends against the routine administration of probiotics to preterm infants, particularly the most vulnerable (those whose birth weight is <1000 g), for the treatment or prevention of necrotizing enterocolitis (NEC) and late-onset sepsis.

Although probiotics are increasingly given to preterm infants, the AAP notes that the data on their safety and efficacy are inconsistent. In addition, the supplements are not subject to approval by the US Food and Drug Administration (FDA).

Therefore, the academy advises clinicians to use extreme caution in selecting preterm neonates to receive these microorganisms and recommends obtaining informed consent from parents after carefully discussing the risks. It also recommends that centers using probiotics conduct surveillance, inasmuch as probiotics can alter a center's flora, potentially affecting all patients. Such centers should also carefully document outcomes, adverse events, and safety.

The AAP's clinical report, published online May 24 in Pediatrics, highlights wide differences between commercially available formulations and a lack of regulatory standards in this country.

Dr Brenda Poindexter

Absent FDA-approved drug labeling, these nutritional supplements cannot be marketed as treatment or prophylaxis, but that has scarcely stopped their use. "Despite lack of availability of a pharmaceutical-grade product, the number of preterm infants receiving probiotics in the United States and Canada is steadily increasing," write Brenda Poindexter, MD, FAAP, chief of neonatology at Children's Healthcare of Atlanta, in Atlanta, Georgia, and members of the AAP's Committee on Fetus and Newborn.

Analyses of US collaborative databases indicate that approximately 10% of neonates of extremely low gestational age receive a probiotic preparation in the neonatal intensive care unit (NICU). The use of these preparations varies widely across institutions.

"NEC is a devastating morbidity of prematurity, and it's multifactorial. Some babies only given mother's milk still get NEC, and the decision to use these products is a very nuanced one," Poindexter told Medscape Medical News. "I suspect some people will disagree with the report, and we tried to give folks some wiggle room."

Evidence from other countries suggests that probiotics can be protective against NEC, she added, "so not to have a reliable product in this country is very frustrating."

Poindexter and colleagues point to a 2015 study that found that only 1 of 16 commercial products tested contained the exact organisms listed on their labels. One product contained none of the species listed on the label.

In light of increasing use, the AAP emphasizes the need for development of pharmaceutical-grade probiotics that would be rigorously evaluated for safety and efficacy.

The Infant Microbiome

Over the past decade, the gut microbiome has been increasingly recognized as a factor relevant to health and disease in preterm infants, the authors note. Differences in the intestinal microbiota between full-term and preterm infants are substantial. The microbiome of preterm infants tends to include fewer bacterial species and greater proportions of potentially pathogenic strains.

Evidence of benefit from probiotics has been mixed. Some studies and pooled systematic analyses suggest a significant benefit. However, Poindexter and colleagues note that some researchers express concerns about the study methods used, such as pooling results from trials that tested different probiotic strains or that had few infants in the highest risk category.

Whereas the potential for probiotic-related infection appears low, there does seem to be some risk for sepsis associated with colonization by a strain in a given product or from contamination with a pathogen during manufacturing, the report explains.

At least one trial found that a third of infants randomly assigned to receive placebo showed evidence of the probiotic strain.

"However, it may be difficult to distinguish the change in the infant from the change in the resident flora of the NICU," the AAP panel writes.

In addition, there have recently been several recalls of dietary supplement–grade probiotics for contamination, which have raised concerns. Pathogens include Salmonella, Rhizopus, and Penicillium species. Fatal gastrointestinal mucormycosis has also been reported in a preterm infant who received ABC Dophilus powder that was contaminated with the microfungus Rhizopus oryzae.

Other safety considerations, according to the authors, are the unknown longer-term effect of probiotics on preterm infants and the unknown impact of microorganisms on the microbiome over time.

Last year, the European Society for Pediatric Gastroenterology, Hepatology and Nutrition published a position paper with a conditional recommendation for selected probiotics to reduce NEC rates. "These guidelines would be applicable in the US if we had products manufactured in a way that could guarantee that what's on the label is in the bottle," Poindexter said.

Dr Erica Wymore

Asked for her perspective on the AAP clinical report, Erica Wymore, MD, an assistant professor of neonatal and perinatal medicine at the University of Colorado, in Aurora, Colorado, called it "an excellent review of the current literature" that shows the inadequacy of data on the composition, dosage, timing, duration, and use of single-strain vs multiple-strain probiotics to reduce NEC. Her clinical center, the Children's Hospital Colorado, does not administer probiotics to preterm babies.

Although guidelines can improve outcomes, continued Wymore, who was not involved in the AAP report, improvement observed with probiotics results from more stringent care in centers that experience high NEC rates. "It's hard to know if it's due to the probiotics if they already have a high rate of NEC," Wymore said.

She echoed the AAP's position and stresses the need for extreme caution in giving these products to vulnerable infants with immature immune systems. Before that can be safely done, she said, "we need more FDA oversight of product composition, pharmaceutical-grade products, and more studies to determine efficacy."

Added Poindexter, "Hopefully, this report will inform clinicians of the risks of using non–pharmaceutical-grade products and encourage industry to actually develop probiotics for neonates that we can feel comfortable using."

The report received no external funding. Poindexter and Wymore have disclosed no relevant financial relationships.

Pediatrics. Published online May 24, 2021. Full text

Diana Swift is medical journalist based in Toronto.

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