A1 Refereed original research article in a scientific journal

Early-life formula feeding is associated with infant gut microbiota alterations and an increased antibiotic resistance load




AuthorsParnanen, Katariina M. M.; Hultman, Jenni; Markkanen, Melina; Satokari, Reetta; Rautava, Samuli; Lamendella, Regina; Wright, Justin; McLimans, Christopher J.; Kelleher, Shannon L.; Virta, Marko P.

PublisherELSEVIER SCIENCE INC

Publishing placeNEW YORK

Publication year2022

JournalAmerican Journal of Clinical Nutrition

Journal name in sourceAMERICAN JOURNAL OF CLINICAL NUTRITION

Journal acronymAM J CLIN NUTR

Volume115

Issue2

First page 407

Last page421

Number of pages15

ISSN0002-9165

eISSN1938-3207

DOIhttps://doi.org/10.1093/ajcn/nqab353


Abstract
Background Infants are at a high risk of acquiring fatal infections, and their treatment relies on functioning antibiotics. Antibiotic resistance genes (ARGs) are present in high numbers in antibiotic-naive infants' gut microbiomes, and infant mortality caused by resistant infections is high. The role of antibiotics in shaping the infant resistome has been studied, but there is limited knowledge on other factors that affect the antibiotic resistance burden of the infant gut. Objectives Our objectives were to determine the impact of early exposure to formula on the ARG load in neonates and infants born either preterm or full term. Our hypotheses were that diet causes a selective pressure that influences the microbial community of the infant gut, and formula exposure would increase the abundance of taxa that carry ARGs. Methods Cross-sectionally sampled gut metagenomes of 46 neonates were used to build a generalized linear model to determine the impact of diet on ARG loads in neonates. The model was cross-validated using neonate metagenomes gathered from public databases using our custom statistical pipeline for cross-validation. Results Formula-fed neonates had higher relative abundances of opportunistic pathogens such as Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Klebsiella oxytoca, and Clostridioides difficile. The relative abundance of ARGs carried by gut bacteria was 69% higher in the formula-receiving group (fold change, 1.69; 95% CI: 1.12-2.55; P = 0.013; n = 180) compared to exclusively human milk-fed infants. The formula-fed infants also had significantly less typical infant bacteria, such as Bifidobacteria, that have potential health benefits. Conclusions The novel finding that formula exposure is correlated with a higher neonatal ARG burden lays the foundation that clinicians should consider feeding mode in addition to antibiotic use during the first months of life to minimize the proliferation of antibiotic-resistant gut bacteria in infants.



Last updated on 2025-27-01 at 19:45