Candidatus Mycoplasma girerdii replicates, diversifies, and co-occurs with Trichomonas vaginalis in the oral cavity of a premature infant

• Published in: Scientific reports Vol. 7; no. 1; pp. 3764 - 11
• Main Authors: Costello, Elizabeth K, Sun, Christine L, Carlisle, Erica M, Morowitz, Michael J, Banfield, Jillian F, Relman, David A
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 19.06.2017; Nature Publishing Group UK; Nature Portfolio
• Subjects: 60 APPLIED LIFE SCIENCES; Candidatus Mycoplasma girerdii; Deoxyribonucleic acid; DNA; DNA sequencing; Female; Ferredoxin; Genomes; Humans; Infant, Newborn; Lung diseases; Male; Metronidazole; Mouth - microbiology; Mouth - pathology; Mycoplasma - genetics; Mycoplasma - growth & development; Mycoplasma Infections - genetics; Mycoplasma Infections - metabolism; Mycoplasma Infections - microbiology; Mycoplasma Infections - pathology; Neonates; Oral cavity; Parasitic diseases; Population genetics; Premature birth; Pyruvate-ferredoxin oxidoreductase; Pyruvic acid; Restriction-modification; rRNA 16S; Saliva; Sexually transmitted diseases; STD; Trichomonas Infections - genetics; Trichomonas Infections - metabolism; Trichomonas Infections - microbiology; Trichomonas Infections - pathology; Trichomonas vaginalis; Trichomonas vaginalis - genetics; Trichomonas vaginalis - growth & development
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-03821-7

Genital mycoplasmas, which can be vertically transmitted, have been implicated in preterm birth, neonatal infections, and chronic lung disease of prematurity. Our prior work uncovered 16S rRNA genes belonging to a novel, as-yet-uncultivated mycoplasma (lineage 'Mnola') in the oral cavity of a premature neonate. Here, we characterize the organism's associated community, growth status, metabolic potential, and population diversity. Sequencing of genomic DNA from the infant's saliva yielded 1.44 Gbp of high-quality, non-human read data, from which we recovered three essentially complete (including 'Mnola') and three partial draft genomes (including Trichomonas vaginalis). The completed 629,409-bp 'Mnola' genome (Candidatus Mycoplasma girerdii str. UC-B3) was distinct at the strain level from its closest relative, vaginally-derived Ca. M. girerdii str. VCU-M1, which is also associated with T. vaginalis. Replication rate measurements indicated growth of str. UC-B3 within the infant. Genes encoding surface-associated proteins and restriction-modification systems were especially diverse within and between strains. In UC-B3, the population genetic underpinnings of phase variable expression were evident in vivo. Unique among mycoplasmas, Ca. M. girerdii encodes pyruvate-ferredoxin oxidoreductase and may be sensitive to metronidazole. This study reveals a metabolically unique mycoplasma colonizing a premature neonate, and establishes the value of genome-resolved metagenomics in tracking phase variation.