Controlled human infection with Neisseria lactamica in late pregnancy to measure horizontal transmission and microbiome changes in mother–neonate pairs: a single-arm interventional pilot study protocol

• Published in: BMJ open Vol. 12; no. 5; p. e056081
• Main Authors: Theodosiou, Anastasia A, Laver, Jay R, Dale, Adam P, Cleary, David W, Jones, Christine E, Read, Robert C
• Format: Journal Article
• Language: English
• Published: England British Medical Journal Publishing Group 18-05-2022; BMJ Publishing Group LTD; BMJ Publishing Group
• Series: Protocol
• Subjects: Adult; Adults; Babies; Bacteria; Child; Child, Preschool; Female; Genomes; Good Manufacturing Practice; Health care; Humans; Hypotheses; Immunization; Immunocompetence; Infant; Infant, Newborn; Infectious Diseases; Manufacturing; microbiology; Microbiota; Microbiota - genetics; Mothers; Neisseria lactamica - genetics; Neisseria meningitidis; Newborn babies; paediatric infectious disease & immunisation; Pediatrics; Pharynx; Pilot Projects; Pregnancy; Probiotics; respiratory infections; RNA, Ribosomal, 16S; Staphylococcus infections; Streptococcus infections; Vaccines; Virulence; Womens health; microbiology; respiratory infections; paediatric infectious disease & immunisation
• ISSN: 2044-6055; 2044-6055
• DOI: 10.1136/bmjopen-2021-056081

IntroductionInfant upper respiratory microbiota are derived partly from the maternal respiratory tract, and certain microbiota are associated with altered risk of infections and respiratory disease. Neisseria lactamica is a common pharyngeal commensal in young children and is associated with reduced carriage and invasive disease by Neisseria meningitidis. Nasal inoculation with N. lactamica safely and reproducibly reduces N. meningitidis colonisation in healthy adults. We propose nasal inoculation of pregnant women with N. lactamica, to establish if neonatal pharyngeal colonisation occurs after birth, and to characterise microbiome evolution in mother–infant pairs over 1 month post partum.Methods and analysis20 healthy pregnant women will receive nasal inoculation with N. lactamica (wild type strain Y92-1009) at 36–38 weeks gestation. Upper respiratory samples, as well as optional breastmilk, umbilical cord blood and infant venous blood samples, will be collected from mother–infant pairs over 1 month post partum. We will assess safety, N. lactamica colonisation (by targeted PCR) and longitudinal microevolution (by whole genome sequencing), and microbiome evolution (by 16S rRNA gene sequencing).Ethics and disseminationThis study has been approved by the London Central Research Ethics Committee (21/PR/0373). Findings will be published in peer-reviewed open-access journals as soon as possible.Trial registration number NCT04784845.