Genomic diversity and antimicrobial resistance of Prevotella spp. isolated from chronic lung disease airways

Cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are characterised by increasingly frequent acute pulmonary exacerbations that reduce life quality and length. Human airways are home to a rich polymicrobial environment, including members of the obligately anaerobic genus, Prevotella. Despite their commonness, surprisingly little is known about the prevalence, role, genomic diversity, and antimicrobial resistance (AMR) potential of Prevotella species/strains in healthy and diseased airways. Here, we used comparative genomics to develop a real-time PCR assay to permit rapid Prevotella spp. quantification from cultures and clinical specimens. Assay specificity was validated across a panel of Prevotella and non-Prevotella species, followed by PCR screening of CF and COPD respiratory-derived cultures. Next, 35 PCR-positive isolates were subjected to whole-genome sequencing. Of eight identified species, P. histicola, P. melaninogenica, P. nanceiensis, P. salivae and P. denticola overlapped between participant cohorts. Phylogenomic analysis revealed considerable interhost but limited intrahost diversity, indicating patient-specific lineages rather than patient-to-patient transmission. Correlation of phenotypic AMR profiles with AMR gene presence identified excellent correlation between tetQ presence and decreased doxycycline susceptibility, and ermF presence and decreased azithromycin susceptibility and clindamycin resistance. AMR rates were higher in the CF isolates, reflecting greater antibiotic use in this cohort. All tested Prevotella isolates were tobramycin-resistant, providing a potential selection method to improve Prevotella culture retrieval rates. Our addition of 35 airway-derived Prevotella genomes to public databases will enhance ongoing efforts to unravel the role of this diverse and enigmatic genus in both chronic respiratory diseases and healthy lungs.