2374. Genomic Characteristics of Recurrent Staphylococcus aureus Skin and Soft Tissue Infection among US Army Trainees
Session: Poster Abstract Session: Skin and Skin Structure Infection
Saturday, October 6, 2018
Room: S Poster Hall
Posters
  • 2374_IDWPOSTER.pdf (191.0 kB)
  • Background: Skin and soft tissue infections (SSTI) are common among military recruits, and some experience recurrent SSTI (two infections ≥30 days apart) during training. We used whole genome sequencing (WGS) to assess the relatedness of strains from recurrent S. aureus SSTI cases and their close contacts.

    Methods: From 2010-2014, we prospectively identified SSTI cases among US Army Infantry trainees (Fort Benning, GA), obtaining infection swabs at the time of presentation for all SSTIs and multiple anatomic site colonization swabs at the time of presentation for the first infection. Thereafter, we selected cases of recurrent S. aureus SSTI with phenotypically concordant paired isolates (e.g., MRSA-MRSA). We also selected concordant colonization isolates from recurrent cases as well as concordant infection isolates from SSTI cases in the same training class as the recurrent case. Isolates were characterized by WGS. The number of single nucleotide polymorphism (SNP) differences between isolates was calculated. Phylogenetic trees were constructed to identify patterns of intra- vs. extra-host S. aureus acquisition among cases of recurrent infection.

    Results: We identified 23 cases of recurrent S. aureus SSTI with concordant infection isolates (18 MRSA). The median (range) pairwise SNP difference for intrahost infection isolates was 15 (0-3768); 12 (0-348), MRSA and 310 (3-3768), MSSA. Nine (39%) were colonized with a concordant strain (5 MRSA), yielding 14 colonization isolates (7 MRSA). The median pairwise SNP difference between intrahost colonization and recurrent infection isolates was 57 (2-3582); 5 (2-3582), MRSA and 167 (2-313), MSSA. Infection isolates from 33 proximal cases (27 MRSA) were identified. The median pairwise SNP difference between recurrent infection isolates and that of a proximal case was 24 (1-531); 20 (1-216), MRSA and 307 (286-531), MSSA. Variant analysis showed no difference between the number of putative high impact SNPs between infection (μ=11, σ=20) and colonization (μ=19, σ=42) isolates.

    Conclusion: WGS of S. aureus from recurrent SSTI suggests patterns of intra-host reinfection as well as intra-host acquisition/infection. Targeted decolonization may prevent recurrent S. aureus SSTI.

    Kathleen Verratti, BA1, Robert Player, MS1, Shannon Wood, MD, MPH2, Carey Schlett, MPH3,4, Emad Elassal, MS5, Ellen Forsyth, MS1, Michael Ellis, MD6, David R. Tribble, MD, DrPH3, Eugene Millar, PhD3,4 and Jason Bennett, MD, MSPH7,8, (1)Johns Hopkins Applied Physics Laboratory, Laurel, MD, (2)Infectious Diseases, Walter Reed National Military Medical Center, Bethesda, MD, (3)Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, (4)Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, (5)International Reagent Resource, American Type Tissue Collection, Manassas, VA, (6)University of Toledo College of Medicine and Life Sciences, Toledo, OH, (7)Walter Reed Army Institute of Research, Silver Spring, MD, (8)Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD

    Disclosures:

    K. Verratti, None

    R. Player, None

    S. Wood, None

    C. Schlett, None

    E. Elassal, None

    E. Forsyth, None

    M. Ellis, None

    D. R. Tribble, None

    E. Millar, None

    J. Bennett, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.