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

Zhigang Qiu,Zhixian Gao,Min Jin,Jiping Yang,Zhongwei Yang,Haibei Li,Haixia Shi,Weili Liu,Jing Yin,Kunming Zhang,Dong Yang,Huaran Wang,Jun-Wen Li,Yaqiong Chen,Danyang Shi,Zhiqiang Shen

doi:10.1186/s12866-022-02447-8

Zhigang Qiu, Zhixian Gao + Show 14 more

Open Access

https://doi.org/10.1186/s12866-022-02447-8

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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.

Highlights

The gut is the largest digestive organ of the human body, houses a complex microbial flora and acts as a reservoir of antibiotic resistance genes (ARGs) [1]
ARGs in faeces of neonates No bacteria were detected in meconium samples from caesarean section newborns (16S rRNA analysis by quantitative PCR was negative), and no ARGs were detected in meconium samples
In this study, nine types of most common ARGs were detected in 82 pairs of neonatal faeces and maternal amniotic fluid, colostrum samples, ward air and drinking water samples

Summary

Introduction

The gut is the largest digestive organ of the human body, houses a complex microbial flora and acts as a reservoir of antibiotic resistance genes (ARGs) [1]. The birth canal contains a large number of bacteria that may include ARGs, and during childbirth neonates may acquire bacteria from the vagina [11]. Previous studies do not exclude the effects of bacteria in the birth canal during delivery and the use of antibiotics and probiotics by mothers when they concluded that bacteria in the mother’s gut and breast milk might be a source of ARGs in the gut of newborns [19]. Several studies included too few subjects to achieve statistically significant conclusions [19, 20] These studies could not directly confirm the source of ARGs. where and when ARGs are acquired during childbirth remains unclear, as does the types of ARGs acquired. By finding out “where and when ARGs are acquired during childbirth”, we hope to take relevant measures to eliminate the contact of neonatal drug-resistant bacteria and reduce or prevent the threat of drug-resistant bacteria to newborns

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Conclusion