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Published on: February 9, 2011
Bacterial Etiology and Risk Factors Associated with Cellulitis and Purulent Skin Abscesses in Military Trainees
Ryan C Johnson1, Michael W Ellis2, Carey D Schlett3
1Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Abstract:
Military trainees are at high risk for skin and soft-tissue infections (SSTIs). Although Staphylococcus aureus is associated with purulent SSTI, it is unclear to what degree this pathogen causes nonpurulent cellulitis. To inform effective prevention strategies and to provide novel insights into SSTI pathogenesis, we aimed to determine the etiology of SSTI in this population. We conducted a prospective observational study in US Army Infantry trainees with SSTI (cutaneous abscesses and cellulitis) from July 2012 through December 2014. We used standard microbiology, serology, and high-throughput sequencing to determine the etiology of SSTI. Furthermore, we compared purported risk factors as well as anatomic site colonization for S. aureus. Among 201 SSTI cases evaluated for SSTI risk factors, cellulitis was associated with lower extremity blisters (P = 0.01) and abscess was associated with methicillin-resistant S. aureus (MRSA) colonization (P<0.001). Among the 22 tested cellulitis cases that were part of the microbiome analysis, only 1 leading edge aspirate was culturable (Coagulase-negative Staphylococcus). Microbiome evaluation of aspirate specimens demonstrated that Rhodanobacter terrae was the most abundant species (66.8% average abundance), while abscesses were dominated by S. aureus (92.9% average abundance). Although abscesses and cellulitis share the spectrum of clinical SSTI, the bacterial etiologies as determined by current technology appear distinct. Furthermore, the presence of atypical bacteria within cellulitis aspirates may indicate novel mechanisms of cellulitis pathogenesis.
Clinical Trials Registration:
NCT01105767.
Insights
Military trainees experience high rates of skin infections. Abscesses are linked to Staphylococcus aureus, while cellulitis may involve different bacteria, suggesting distinct causes for these common infections.
Area of Science:
- Infectious Diseases
- Microbiology
- Military Health
Background:
- Military trainees are a high-risk population for skin and soft-tissue infections (SSTIs).
- The specific causative agents of purulent versus nonpurulent SSTIs, particularly cellulitis, in this demographic remain incompletely understood.
- Clinical trial registration: NCT01105767.
Purpose of the Study:
- To determine the distinct etiologies of cutaneous abscesses and cellulitis in US Army Infantry trainees.
- To identify risk factors and colonization patterns associated with Staphylococcus aureus in SSTIs.
- To gain insights into the pathogenesis of SSTIs for improved prevention strategies.
Main Methods:
- Prospective observational study of US Army Infantry trainees with SSTIs from July 2012 to December 2014.
- Utilized standard microbiology, serology, and high-throughput sequencing for etiological determination.
- Compared risk factors and S. aureus colonization sites; analyzed microbiome of aspirate specimens.
Main Results:
- Cellulitis cases were associated with lower extremity blisters (P = 0.01), while abscesses were linked to methicillin-resistant S. aureus (MRSA) colonization (P<0.001).
- Microbiome analysis of cellulitis aspirates revealed Rhodanobacter terrae as the most abundant species (66.8%), with limited culturable bacteria.
- Abscess aspirates were predominantly caused by S. aureus (92.9% average abundance).
Conclusions:
- Abscesses and cellulitis in military trainees appear to have distinct bacterial etiologies based on current diagnostic technologies.
- The presence of atypical bacteria like R. terrae in cellulitis suggests novel pathogenic mechanisms.
- Findings highlight the need for differentiated approaches to diagnosing and treating SSTIs in this population.
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