Army Lieutenant Colonel Michael Ellis, M.D., was the 2014 recipient of the John F. Maher Award for Research Excellence in the Department of Medicine, Uniformed Services University (USU). The award recognizes research that represents a significant contribution to the understanding, remedy or prevention of disease or an innovative contribution to medical education. Dr. Ellis, an Associate Professor in the department, also received the William Crosby Superiority in Research Award from the Army Chapter of the American College of Physicians, as well as the Army A Specialty Designator from the Army Medical Department (AMEDD). These awards were presented to Dr. Ellis by Dean Arthur Kellermann, Dean of the School of Medicine, and Brigade Commander Col Kevin Glasz during a USU Department of Medicine faculty meeting on December 2nd. These awards recognize Dr. Ellis' achievements as a clinical researcher, underscored by his leadership of IDCRP-055, a field-based, cluster-randomized trial of personal hygiene measures to prevent skin and soft tissue infections (SSTI) among military trainees at Fort Benning, GA. In addition to evaluating the effectiveness of hygiene against SSTI, this study has yielded a wealth of data with respect to the epidemiology, pathogenesis, immunology, and microbiome of SSTI in a population known to be at increased risk for Staphylococcus aureus colonization and disease.
A few highlights of these activities are provided below:
• In general, personal hygiene-based measures, including weekly use of a chlorhexidine (CHG)-based body wash, were ineffective at preventing SSTI in trainees. There was, however, an observed reduction in methicillin-resistant S. aureus (MRSA) SSTI rates among CHG-randomized trainees during the summer months, the peak period for MRSA colonization and SSTI (Ellis ME et al., Clinical Infectious Diseases 2014).
• Among ~10,000 trainees randomized to receive CHG, the overall prevalence of CHG-resistant MRSA isolates was low. Moreover, at the conclusion of the 20-month study period, we found no association between extended use of CHG and the emergence of CHG-resistance among MRSA isolates at Fort Benning (Schlett CD et al., Antimicrobial Agents and Chemotherapy 2014).
• Colonization is thought to be a prerequisite for S. aureus infection. Investigators examined the relatedness of colonization and clinical S. aureus isolates in individuals with SSTI and found, on the phenotypic level, a higher degree of concordance between colonization and clinical isolates with methicillin-susceptible S. aureus (MSSA) than with MRSA. However, when accounting for molecular characteristics (i.e. pulsed field type), there was a higher degree of concordance with MRSA isolates, the vast majority of which were the USA300 strain (Ellis ME et al., Infection Control and Hospital Epidemiology 2014).
• Evaluation of the nasal microbiome of trial participants, comparing those with versus those without SSTI, as well as those who were colonized versus those were not colonized with S. aureus, revealed significant differences in microbial ecology between groups. Findings from this study suggest that nasal colonization with certain bacteria may confer some protection against SSTI (Johnson RC et al., Infection and Immunity, accepted for publication).
• While weekly use of CHG-based body wash did not prevent SSTI, analysis of colonization data revealed that frequent users of the wash were ~50% less likely to be colonized with MRSA in the nose (Millar EV et al., Antimicrobial Agents and Chemotherapy, accepted for publication). Follow-up studies are needed to evaluate whether decolonization interrupts the transmission and acquisition of MRSA in congregate settings, and whether this should be a component of future SSTI prevention strategies.
• It is well-known that promotion of personal hygiene (e.g. handwashing, use of alcohol-based hand sanitizers, etc.) can prevent transmission and acquisition of infectious diseases in congregate settings. Investigators reviewed rates of acute gastroenteritis (AGE) among trainees during the trial period, and found that AGE rates were 20-30% lower among study groups randomized to receive supplemental training and education on personal hygiene practices (D’Onofrio MJ et al., Infection Control and Hospital Epidemiology, accepted).
Knowledge gleaned from these studies of SSTI and AGE is critical for the development of disease treatment and prevention strategies in this particularly vulnerable population of military trainees. Thanks to the efforts of LTC Ellis and the SSTI investigative team, much has already been accomplished, and the foundation for future efforts in this research area has been solidified.