Antibiotic resistance genes in gut of breast-fed neonates born by caesarean section originate from breast milk and hospital ward air

Abstract

The human gut is a reservoir of antibiotic resistance genes (ARGs). Even in the absence of antibiotics, ARGs are present in large quantities in faeces of adults, children and even newborns. However, where and when ARGs are acquired remains unclear, as does the types of ARGs acquired. Herein, we recruited 82 pairs of women and their caesarean section newborns. Conventional culture methods and quantitative PCR were employed to detect nine species and six ARG types in meconia, faeces from 3-day-old newborns, amniotic fluid, colostrum, and hospital ward air samples. Furthermore, ARG transfer was explored by tracking Staphylococcus epidermidis isolated from faeces of 3-day-old newborns, colostrum and ward air samples using multi-locus sequence typing (MLST). No ARGs or microorganisms were detected in meconia or amniotic fluid. One or more ARGs were detected in 90.2% of faeces from 3-day-old newborns, and the mecA gene exhibited the highest detection rate (45.1%). ARGs were detected in 85.4% of colostra consistent with ARGs in faeces from 3-day-old newborns. Some ARGs were detected in ward air, and might also be a source of ARGs in neonatal faeces. Isolation of S. epidermidis from neonatal faeces was consistent with antibiotic resistance and gene profiles for colostrum samples. Traceability analysis of S. epidermidis showed that ARGs in neonatal faeces mainly originated from colostrum, and partly from ward air. After birth, neonates born by caesarean section obtain a variety of ARGs mainly from colostrum, and partly from ward air.

Metagenomics analysis of the neonatal intestinal resistome

“…This is likely because delivery mode has a strong effect on the phylogenetic composition of the intestinal microbiome. Vertical transmission of ARGs from mothers to neonates occurs through contact, either during delivery with the genital tract or later through contact with the nasopharyngeal, oral, and skin microbiome (26, [35][36][37]. Neonates born vaginally are, therefore, likely colonised by ARGs from the maternal vaginal and intestinal microbiome, whereas infants born by CS predominantly acquire ARGs from the maternal skin microbiome (4).…”

The role of Bifidobacterium genus in modulating the neonate microbiota: implications for antibiotic resistance acquisition in early life

“…The quantified ARGs were chosen according to their importance and high prevalence in infant resistome as described elsewhere. 2 , 3 , 15–18 Each reaction mixture of 10 μL was composed of 5 μL SYBR GreenPCR Master Mix (Roche Technologies, Basel, Switzerland), 0.25 μL of each of the primers at a concentration of 10 μM, 3.5 μL of distilled water and 1 μL of DNA. The amplification conditions were 35 cycles of: initial denaturation at 95°C for 5 min denaturation at 95°C for 30 s, specific annealing temperature for each primer pair 19 for 30 s, and a final extension step of 72°C for 30 s. The qPCR results were calculated as the antibiotic resistance gene copies per sample (log copies/µl).…”

The effect of early colonized gut microbiota on the growth performance of suckling lambs

“…To collect samples of microbiota in air, six sampling points were arranged in the front, middle, and rear sections of the pens, and the samples were collected using the natural sedimentation method following a previous publication (Zhang et al, 2022). Each Petri dish was exposed to air for 30 min, then a sterile swab was used to dip the surface of the Petri dish, transferred into a cryogenic storage tube, and stored at −80°C for testing.…”