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  • Use of antibiotics would be expected to alter

    2024-02-22

    Use of hexamethonium would be expected to alter the maternal microbiome, thereby changing the infant's initial exposure is to the microbial environment, which could potentially lead to an abnormal succession of microbial colonization in the infant. Alterations in early microbial transfer and succession could have significant downstream effects, as the maternal microbiome has been shown to promote development of neonatal immunity. For example, Deshmukh et al showed neonatal mice from dams exposed to antibiotics had a decreased number of intestinal microbes, altered structure of the microbiota and colonization, decreased bone marrow neutrophils and granulocyte/macrophage progenitor cells, reduced interleukin-17–producing cells in intestine, and consequent production of granulocyte colony-stimulating factor. Relative granulocytopenia contributed to increased susceptibility of antibiotic-exposed neonatal mice to E coli K1 and Klebsiella pneumoniae sepsis. Transplacental passage of maternal antibiotics also may directly alter the neonatal microbiome, reducing microbial diversity and creating a preponderance of pathogenic bacteria. It is well established that maternal antibiotics cross the placenta to reach the fetus. Mazzola et al demonstrated that infants whose mothers received intrapartum antibiotic prophylaxis against GBS had an abundance of Enterobacteriaceae compared with control infants. As previous studies have shown, dysbiosis of the neonatal microbiome has been associated increasingly with development of disease. We have reported previously that early dysbiosis strongly predicts NEC. Stool samples from patients with NEC had lower bacterial diversity, lacked Propionibacterium, and were dominated by either Firmicutes or Proteobacteria, compared with controls. Based on a meta-analysis of cohort studies in diverse locations, Pammi et al reported a greater relative abundance of Proteobacteria and decreased Firmicutes and Bacteroidetes in patients with NEC. However, NEC and LOS are multifactorial diseases, and risk factors should not be considered in a vacuum. Different microbes or forms of dysbiosis may distinguish the etiologies of NEC11, 27 and LOS, which may account for the opposite effects of prenatal antibiotics on NEC and LOS seen in our study. Strengths of our study were that it includes a relatively large number of participants and our cohort was representative of the neonatal population at high-risk referral centers in 2 large US catchment areas. Because we previously reported temporal, regional, and interinstitutional differences between the neonatal microbiome in this cohort, our findings may not be completely generalizable to other centers for delivery of high-risk infants. The results of our study are compelling enough to warrant further research.
    Introduction Antibiotics are widely used in human medicine as well as in animal and fish farming for illness prevention, disease treatment and growth promotion (USEPA, 2012). They are pseudo-persistent compounds because of their continuous input into the environment and permanent presence (Sarmah et al., 2006, Van Boeckel et al., 2015). The Pearl River Delta (PRD) is a major agricultural region in southern China where large quantities of vegetables and edible crops are produced and exported from. Because of water supply shortages that result from climate change, urbanization, regional drought and pollution, untreated wastewater is commonly used to irrigate agricultural land in arid and semi-arid regions (IPCC. Intergovernmental Panel on Climate Change, 2009, WWAP. World Water Assessment Programme, 2012). The use of wastewater for irrigation in agricultural land carries multiple economic and environmental benefits. However, the broad agricultural application of wastewater faces a new challenge: more than 10 million hectares of arable land in China have been contaminated by heavy metals and organic pollutants, while 3.3 million hectares have been contaminated as a result of wastewater irrigation (DAGDP, 2013). Studies from the past two decades showed that antibiotics are present in increasing concentrations in untreated wastewater (Awad et al., 2014, Watkinson et al., 2009), and most of these agents are biologically active and create potential risks to the environment (Chen et al., 2011, Pan and Chu, 2017a, Papadopoulos et al., 2009, Yan et al., 2013). Antibiotics are frequently detected in the soil in recent years, with concentrations varying from ng/g to the low μg/g (Li et al., 2015, Li et al., 2011b, Pan et al., 2014). Therefore, wastewater irrigation may be strongly associated with the significant increases in residual antibiotic concentrations in agricultural soils in the Pearl River Delta Region (Pan and Chu, 2015, Pan and Chu, 2016, Pan and Chu, 2017b).