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Updated: Aug 30, 2025
Oral Biofilm Sampling for Microbiome Analysis in Healthy Children
Published on: December 31, 2017
Genomic characterization of Staphylococcus aureus isolates causing osteoarticular infections in otherwise healthy
Walter Dehority1, Valerie J Morley2, Daryl B Domman2
1Department of Pediatrics, The University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America.
Insights
Staphylococcus aureus causing pediatric bone and joint infections show genetic diversity. These bacteria more often carry immune evasion genes, but mutations are rare, suggesting other regulatory mechanisms are key.
Area of Science:
- Microbiology
- Infectious Diseases
- Genomics
Background:
- Pediatric osteoarticular infections are frequently caused by Staphylococcus aureus.
- The role of Staphylococcus aureus genomic variability in the pathogenesis of these infections is not well understood.
Purpose of the Study:
- To investigate the genomic variability of Staphylococcus aureus isolates from children with varying degrees of S. aureus infection.
- To correlate genetic features with the clinical presentation and biofilm-forming capacity of S. aureus.
Main Methods:
- Whole genome sequencing of S. aureus isolates from 47 children (skin colonization, skin abscesses, osteoarticular infections).
- Assessment of 254 virulence genes, mutations, and phylogenetic analysis.
- Comparison of biofilm formation capacity among isolates.
Main Results:
- No specific sequence types predominated in osteoarticular infections.
- Isolates from osteoarticular infections more frequently carried immune evasion genes (p = .02).
- Limited mutations were found in virulence genes, and biofilm formation varied significantly, with control isolates showing more robust biofilm formation.
Conclusions:
- Staphylococcus aureus causing pediatric osteoarticular infections are genetically diverse.
- These isolates possess more immune evasion genes but similar overall virulence gene carriage compared to less invasive strains.
- Pathogenesis may be primarily regulated at transcriptional and/or translational levels due to infrequent mutations.
Background:
Pediatric osteoarticular infections are commonly caused by Staphylococcus aureus. The contribution of S. aureus genomic variability to pathogenesis of these infections is poorly described.
Methods:
We prospectively enrolled 47 children over 3 1/2 years from whom S. aureus was isolated on culture-12 uninfected with skin colonization, 16 with skin abscesses, 19 with osteoarticular infections (four with septic arthritis, three with acute osteomyelitis, six with acute osteomyelitis and septic arthritis and six with chronic osteomyelitis). Isolates underwent whole genome sequencing, with assessment for 254 virulence genes and any mutations as well as creation of a phylogenetic tree. Finally, isolates were compared for their ability to form static biofilms and compared to the genetic analysis.
Results:
No sequence types predominated amongst osteoarticular infections. Only genes involved in evasion of host immune defenses were more frequently carried by isolates from osteoarticular infections than from skin colonization (p = .02). Virulence gene mutations were only noted in 14 genes (three regulating biofilm formation) when comparing isolates from subjects with osteoarticular infections and those with skin colonization. Biofilm results demonstrated large heterogeneity in the isolates' capacity to form static biofilms, with healthy control isolates producing more robust biofilm formation.
Conclusions:
S. aureus causing osteoarticular infections are genetically heterogeneous, and more frequently harbor genes involved in immune evasion than less invasive isolates. However, virulence gene carriage overall is similar with infrequent mutations, suggesting that pathogenesis of S. aureus osteoarticular infections may be primarily regulated at transcriptional and/or translational levels.
