Meconial <i>Methanobrevibacter smithii</i> Suggests Intrauterine Methanogen Colonization in Preterm Neonates

Abstract

Background: Methanogens are part of the human microbiota, the intestinal and oral microbiota. They have even been found in colostrum and breast milk, in vagina only in case of vaginosis and in urinary tract during urinary tract infections. They are present in humans from birth. Accordingly, the detection of methanogens in the meconium has not been reported. The objective of this work was to investigate the presence of methanogens in meconium. Methods: We used a polyphasic approach including microscopy and PCR sequencing in 33 meconium samples taken from 33 premature newborns, in accordance with current ethical regulations. Results: In the presence of negative controls, 90.9% samples were real-time PCR-positive for methanogens and 69.7% were PCR-sequencing positive, identified as Methanobrevibacter (M.) smithii. Further, auto-fluorescent analysis detected methanogens in the two meconium samples analyzed, with a morphology suggesting M. smithii. Multispacer Sequence Typing found M. smithii genotypes ST1 and ST2, previously described as intestinal microbiota inhabitants. C-section delivery and non-use of peripartum antibiotics significantly correlated with PCR-detection of methanogens in meconium. Conclusion: These data position M. smithii among the early inhabitants of the human gut, detectable immediately after birth and suggest the contribution of methanogens to the perinatal development of intestinal microbiota and physiology. Trial Registration: NCT02738411. Funding Statement: YS and COG benefit from PhD grants from the Fondation Mediterranee Infection, Marseille, France. This work was supported by the French Government under the «Investissements d’avenir» (Investments for the Future) program managed by the Agence Nationale de la Recherche (ANR, fr: National Agency for Research), (reference: Mediterranee Infection 10-IAHU-03). Declaration of Interests: The authors declare no competing interests in relation to this study. Outside this study, JV reports speaker and consultancy fees in the past 5 years from Meda Pharma (Mylan), Novartis, Sanofi, Thermo Fisher Scientific, outside the submitted work. Ethics Approval Statement: Written informed parental consent was obtained for each preterm. This research project was approved by the Ethics Committee on Clinical Research of Nimes and Montpellier University Hospitals.