311. Temporal-Spatial Distribution of USA300 MRSA Skin and Soft Tissue Infection among Infantry Trainees at Fort Benning
Session: Poster Abstract Session: HAI: MSSA, MRSA, and other Gram-Positives
Thursday, October 27, 2016
Room: Poster Hall
Posters
  • 311_IDWPOSTER.pdf (93.5 kB)
  • Background: 

    Military trainees are at increased risk for methicillin-resistant Staphylococcus aureus(MRSA) skin and soft tissue infection (SSTI). Pulsed-field type USA300 comprises the majority of MRSA SSTI. We evaluated the temporal-spatial distribution of USA300 MRSA SSTI in a military training environment to elucidate transmission dynamics.

    Methods: 

    We conducted a SSTI case-control study among Army trainees at Fort Benning, GA from 2012-2014. Trainees with SSTI who presented for care were recruited/enrolled. Demographic and risk factor information was collected by interview. Clinical specimens were obtained from subjects with purulent SSTI and processed by standard methods. S. aureusisolates underwent pulsed-field gel electrophoresis (PFGE). To describe patterns of disease transmission within training companies, we restricted the analysis to those groups with ≥5 cases of USA300 MRSA SSTI over the 14-week training period.

    Results: 

    A total of 2,007 SSTI cases from 230 companies were enrolled. There were 2,229 SSTI-associated clinical diagnoses, from which 818 (37%) clinical specimens were obtained. Of these, S. aureus was the primary etiology in 690 (84%) specimens. PFGE was performed on 558 (81%) S. aureusisolates. Of these, 271 (49%) were USA300 MRSA. Fourteen training classes had 5 or more SSTI cases caused by USA300 MRSA (total no. cases: 99; median [range] no. of cases per class: 6.5 [5-12]). Most cases occurred between July and September. The median (range) no. of days between the start of training and the first USA300 MRSA SSTI within classes was 45 (10-81) days. The median (range) no. of days between the first and last cases within classes was 57 (9-91) days. Nine (9%) individuals from eight classes had a recurrent USA300 MRSA SSTI. The median (range) time to recurrence was 59 (31-73) days.

    Conclusion:

    The temporal-spatial distribution of USA300 MRSA SSTI among military trainees suggests an ongoing circulation and ability to cause infections over the course of a training period. We did not observe particular clusters of USA300 MRSA SSTI over time and within classes that could have been characterized as an outbreak of disease. Further characterization of USA300 MRSA strain relatedness (i.e. whole genome sequencing) is warranted.

    Eugene Millar, PhD1, Carey Schlett, MPH1, Jason Bennett, MD, MSPH2, Emad Elassal, MS3, Deepika Mor, MS1, Jeffrey Lanier, MD4, Aaron Starbuck, MD4, David Tribble, MD, DrPH, FIDSA1 and Michael Ellis, MD5, (1)Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University, Rockville, MD, (2)Department of Medicine, Uniformed Services University, Bethesda, MD, (3)Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University, Bethesda, MD, (4)Family Medicine, Martin Army Community Hospital, Fort Benning, GA, (5)University of Toledo College of Medicine and Life Sciences, Toledo, OH

    Disclosures:

    E. Millar, None

    C. Schlett, None

    J. Bennett, None

    E. Elassal, None

    D. Mor, None

    J. Lanier, None

    A. Starbuck, None

    D. Tribble, None

    M. Ellis, 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.