298. Invasive Staphylococcus aureus Infection in Utah Children; Continued Dominance of MSSA over MRSA
Session: Poster Abstract Session: HAI: MSSA, MRSA, and other Gram-Positives
Thursday, October 27, 2016
Room: Poster Hall
Posters
  • Crandall IDSA poster 2016 final.pdf (969.3 kB)
  • Background:

    Staphylococcus aureus is an invasive pathogen causing significant disease in children. Methicillin-resistant S. aureus (MRSA) dominates in many US institutions, but our institution continues to see predominantly methicillin-sensitive S. aureus (MSSA) disease. We sought to characterize the clinical and molecular epidemiology of invasive S. aureus in our population.

    Methods:

    All invasive S. aureus isolates from children 0-18 years treated at Primary Children’s Hospital (PCH; Salt Lake City, Utah) were collected from 2009-2012. Medical records were queried for clinical and laboratory data associated with invasive disease. Next generation sequencing (NGS) was performed on all available isolates (361/363). Multi-locus sequence type (MLST) and presence or absence of the Panton-Valentine leukocidin (PVL) was extracted from NGS data.

    Results:

    We identified 363 children with invasive S. aureus infection. Bone and joint infection was most common (39%), followed by central line associated infection (18%), pneumonia (11%) and endocarditis (2.8%). MSSA caused 80% of invasive infections. While 53% of MRSA were positive for PVL, 94% of MSSA were PVL-negative. PVL (-) MSSA disease was responsible for 71% of ICU admissions. MLST identified 6 predominant S. aureus clusters (ST5, ST8, ST15, ST30, ST45 and ST87). The majority of MRSA were ST5 or ST8, while MSSA were distributed into the remaining 4 clusters. PVL (-) MSSA was over-represented in bone and joint infection while PVL (+) MRSA was over-represented in pneumonia (Table).

    MSSA

    MRSA

    PVL (-)

    PVL (+)

    PVL (-)

    PVL (+)

    Overall (n=361)

    269 (75%)

    17 (5%)

    35 (9%)

    40 (11%)

    Bone and joint (n=137)

    109 (80%)

    8 (6%)

    6 (4%)

    14 (10%)

    Pneumonia (n=40)

    19 (48%)

    1 (2%)

    8 (20%)

    12 (30%)

    Central line associated (n=66)

    55 (83%)

    1 (2%)

    7 (10%)

    3 (5%)

    ICU admission (n=129)

    92 (71%)

    6 (5%)

    17 (13%)

    14 (11%)

    Conclusion:

    Invasive S. aureus disease in Utah has a unique epidemiology, with continued dominance of PVL (-) MSSA. Our MSSA are concentrated in a small number of genetically distinct clusters, suggesting a possible role for novel virulence factors leading to invasive infection. Identification of these factors through NGS and genome-wide association studies could increase our understanding of S. aureus disease in children.

    Hillary Crandall, MD, PhD1, Aurélie Kapusta, PhD2,3, Jarrett Killpack, BSc4, Edgar J. Hernandez, PhD2,3, Mandy Dickey, BSc5, Kody Nilsson, MD4, Judy a. Daly, PhD5,6, Krow Ampofo, MD, FIDSA, FPIDS4, Matthew a. Mulvey, PhD7, Kristina G. Hulten, PhD8, Mark Yandell, PhD2,3 and Anne J. Blaschke, MD, PhD, FIDSA, FPIDS4, (1)Department of Pediatrics, Division of Pediatric Critical Care, University of Utah School of Medicine, Salt Lake City, UT, (2)Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, (3)USTAR Center for Genetic Discovery, Salt Lake City, UT, (4)Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Utah School of Medicine, Salt Lake City, UT, (5)Clinical Microbiology, Primary Children's Hospital, Salt Lake City, UT, (6)Department of Pathology, Division of Clinical Pathology, University of Utah School of Medicine, Salt Lake City, UT, (7)Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT, (8)Baylor College of Medicine and Texas Children's Hospital, Houston, TX

    Disclosures:

    H. Crandall, None

    A. Kapusta, None

    J. Killpack, None

    E. J. Hernandez, None

    M. Dickey, None

    K. Nilsson, None

    J. A. Daly, None

    K. Ampofo, None

    M. A. Mulvey, None

    K. G. Hulten, None

    M. Yandell, None

    A. J. Blaschke, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.