Early-Life Antibiotics Alter Infant Gut Microbiome

Major shift seen in composition and in antimicrobial resistance gene profile directly after treatment, which normalized over 12 months

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THURSDAY, March 10, 2022 (HealthDay News) -- For neonates with suspected early-onset neonatal sepsis (sEONS), the overall gut microbial community composition and antimicrobial resistance gene profile shift directly following antibiotic treatment, according to a study published online Feb. 16 in Nature Communications.

Marta Reyman, from the Wilhelmina Children's Hospital and University Medical Center Utrecht in the Netherlands, and colleagues randomly assigned 147 infants born at ≥36 weeks of gestational age requiring broad-spectrum antibiotics for sEONS treatment (average duration, 48 hours) in their first week of life to receive penicillin + gentamicin, co-amoxiclav + gentamicin, or amoxicillin + cefotaxime. Eighty infants who were not treated with antibiotics from a healthy birth cohort served as controls. Before and immediately after treatment, and at 1, 4, and 12 months of life, rectal swabs and/or feces were collected. Microbiota were characterized, and a panel of 31 antimicrobial resistance genes was tested.

The researchers found that directly following treatment, there was a major shift in the overall gut microbial community composition and antimicrobial resistance gene profile, which normalized over 12 months. Compared with controls, antibiotic-treated infants had decreased abundance of Bifidobacterium spp. and increased abundance of Klebsiella and Enterococcus spp. The largest effect on both the microbial community composition and antimicrobial resistance gene profile was seen for amoxicillin + cefotaxime, while the least effects were observed with penicillin + gentamicin.

"We were surprised with the magnitude and duration of the effects of broad spectrum antibiotics on the infants' microbiome when compared to effects of those same antibiotics on adults' microbiota," a coauthor said in a statement.

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