Can We Optimize Antibiotic Use in Norwegian Neonates? A Prospective Comparison Between a University Hospital and a District Hospital

Effect of antibiotics in the first week of life on faecal microbiota development

BACKGROUND

Infants are frequently exposed to antibiotics (AB) in the first week of life for suspected bacterial infections. Little is known about the effect of AB on the developing intestinal microbiota. Therefore, we studied intestinal microbiota development with and without AB exposure in the first week of life in term born infants.

METHODS

We analysed the faecal microbiota from birth until 2.5 years of age by 16S rRNA gene amplicon sequencing in a cohort with 56 term born infants, exposed to AB in the first week of life (AB+) (AB for 2-3 days (AB2, n=20), AB for 7 days (AB7, n=36)), compared with 126 healthy controls (AB-). The effects of AB and duration were examined in relation to delivery and feeding mode.

RESULTS

AB+ was associated with significantly increased relative abundance of Enterobacteriaceae at 3 weeks and 1 year and a decrease of Bifidobacteriaceae, from 1 week until 3 months of age only in vaginally delivered, but not in C-section born infants. Similar deviations were noted in AB7, but not in AB2. After AB, breastfed infants had lower relative abundance of potentially pathogenic Enterobacteriaceae compared with formula fed infants and recovered 2 weeks faster towards controls.

CONCLUSIONS

AB exposure in the first week of life alters faecal microbiota development with deviations in the relative abundance of individual taxa until 1 year of age. These alterations can have long-term health consequences, which emphasises the need for future studies aiming at restoring intestinal microbiota after AB administration.

Effects of early-life antibiotics on the developing infant gut microbiome and resistome: a randomized trial

Broad-spectrum antibiotics for suspected early-onset neonatal sepsis (sEONS) may have pronounced effects on gut microbiome development and selection of antimicrobial resistance when administered in the first week of life, during the assembly phase of the neonatal microbiome. Here, 147 infants born at ≥36 weeks of gestational age, requiring broad-spectrum antibiotics for treatment of sEONS in their first week of life were randomized 1:1:1 to receive three commonly prescribed intravenous antibiotic combinations, namely penicillin + gentamicin, co-amoxiclav + gentamicin or amoxicillin + cefotaxime (ZEBRA study, Trial Register NL4882). Average antibiotic treatment duration was 48 hours. A subset of 80 non-antibiotic treated infants from a healthy birth cohort served as controls (MUIS study, Trial Register NL3821). Rectal swabs and/or faeces were collected before and immediately after treatment, and at 1, 4 and 12 months of life. Microbiota were characterized by 16S rRNA-based sequencing and a panel of 31 antimicrobial resistance genes was tested using targeted qPCR. Confirmatory shotgun metagenomic sequencing was executed on a subset of samples. The overall gut microbial community composition and antimicrobial resistance gene profile majorly shift directly following treatment (R²= 9.5%, adjusted p-value = 0.001 and R²= 7.5%, adjusted p-value = 0.001, respectively) and normalize over 12 months (R² = 1.1%, adjusted p-value = 0.03 and R²= 0.6%, adjusted p-value = 0.23, respectively). We find a decreased abundance of Bifidobacterium spp. and increased abundance of Klebsiella and Enterococcus spp. in the antibiotic treated infants compared to controls. Amoxicillin + cefotaxime shows the largest effects on both microbial community composition and antimicrobial resistance gene profile, whereas penicillin + gentamicin exhibits the least effects. These data suggest that the choice of empirical antibiotics is relevant for adverse ecological side-effects.

Here, in a randomized trial of 147 infants receiving distinct antibiotic regimens for early-onset neonatal sepsis, Reyman et al. characterize the gut microbiome and resistance profiles, finding differential effects of antibiotic combinations on microbial community composition and antimicrobial resistance genes.

OUP accepted manuscript

Objectives

To investigate whether infants exposed to antimicrobials in hospital during the first 3 months of life had an increased risk of ambulatory antimicrobial use during the following year compared with infants not exposed to antimicrobials during the first 3 months of life.

Methods

Norwegian cohort study of infants less than 3 months consisting of one group exposed to antimicrobials recruited during hospitalization and one group not exposed to antimicrobials. Ten unexposed infants were matched with one exposed infant according to county of residence, birth year and month, and sex. The Norwegian Prescription Database was applied to register antimicrobial use from the month after discharge and 1 year onward. We defined comorbidity based on antimicrobials prescribed as reimbursable prescriptions due to underlying diseases.

Results

Of 95 infants exposed to antimicrobials during the first 3 months of life, 23% had recurrent use compared with 14% use in 950 unexposed infants [relative risk (RR) = 1.7 (95% CI = 1.1–2.5) and comorbidity-adjusted RR = 1.4 (95% CI = 0.9–2.2)]. The recurrence use rate in exposed term infants (≥37 weeks, n = 70) was 27% compared with 12% in their unexposed matches [RR 2.3 = (95% CI = 1.4–3.7) and comorbidity-adjusted RR = 1.9 (95% CI = 1.2–3.2). Of 25 exposed preterm infants, 3 (12%) had recurrent use. The total antimicrobial prescription rate was 674/1000 in the exposed group and 244/1000 in the unexposed group [incidence rate ratio = 2.8 (95% CI = 1.6–4.9)].

Conclusions

Infants exposed to antimicrobials during the first 3 months of life had an increased risk of recurrent use during the following year. This increased risk also appeared in term infants without infection-related comorbidity.