Cutaneous Burn Injury Promotes Shifts in the Bacterial Microbiome in Autologous Donor Skin: Implications for Skin Grafting Outcomes

INTRODUCTION: The cutaneous microbiome maintains skin barrier function, regulates inflammation, and stimulates wound-healing responses. Burn injury promotes an excessive activation of the cutaneous and systemic immune response directed against commensal and invading pathogens. Skin grafting is the primary method of reconstructing full-thickness burns, and wound infection continues to be a significant complication. METHODS: In this study, the cutaneous bacterial microbiome was evaluated and subsequently compared to patient outcomes. Three different full-thickness skin specimens were assessed: control skin from non-burned subjects; burn margin from burn patients; and autologous donor skin from the same cohort of burn patients. RESULTS: We observed that skin bacterial community structure of burn patients was significantly altered compared with control patients. We determined that the unburned autologous donor skin from burn patients exhibits a microbiome similar to that of the burn margin, rather than unburned controls, and that changes in the cutaneous microbiome statistically correlate with several post-burn complications. We established that Corynebacterium positively correlated with burn wound infection, while Staphylococcus and Propionibacterium negatively correlated with burn wound infection. Both Corynebacterium and Enterococcus negatively correlated with the development of sepsis. CONCLUSIONS: This study identifies distinct differences in the cutaneous microbiome between burn subjects and unburned controls, and ascertains that select bacterial taxa significantly correlate with several comorbid complications of burn injury. These preliminary data suggest that grafting donor skin exhibiting bacterial dysbiosis may augment infection and/or graft failure and sets the foundation for more in-depth and mechanistic analyses in presumably "healthy" donor skin from patients requiring skin grafting procedures

Cutaneous Burn Injury Modulates Urinary Antimicrobial Peptide Responses and the Urinary Microbiome

OBJECTIVES: Characterization of urinary bacterial microbiome and antimicrobial peptides after burn injury to identify potential mechanisms leading to urinary tract infections and associated morbidities in burn patients. DESIGN: Retrospective cohort study using human urine from control and burn subjects. SETTING: University research laboratory. PATIENTS: Burn patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Urine samples from catheterized burn patients were collected hourly for up to 40 hours. Control urine was collected from "healthy" volunteers. The urinary bacterial microbiome and antimicrobial peptide levels and activity were compared with patient outcomes. We observed a significant increase in urinary microbial diversity in burn patients versus controls, which positively correlated with a larger percent burn and with the development of urinary tract infection and sepsis postadmission, regardless of age or gender. Urinary psoriasin and β-defensin antimicrobial peptide levels were significantly reduced in burn patients at 1 and 40 hours postadmission. We observed a shift in antimicrobial peptide hydrophobicity and activity between control and burn patients when urinary fractions were tested against Escherichia coli and Enterococcus faecalis urinary tract infection isolates. Furthermore, the antimicrobial peptide activity in burn patients was more effective against E. coli than E. faecalis. Urinary tract infection-positive burn patients with altered urinary antimicrobial peptide activity developed either an E. faecalis or Pseudomonas aeruginosa urinary tract infection, suggesting a role for urinary antimicrobial peptides in susceptibility to select uropathogens. CONCLUSIONS: Our data reveal potential links for urinary tract infection development and several morbidities in burn patients through alterations in the urinary microbiome and antimicrobial peptides. Overall, this study supports the concept that early assessment of urinary antimicrobial peptide responses and the bacterial microbiome may be used to predict susceptibility to urinary tract infections and sepsis in burn patients

The Association between Survival and the Pathologic Features of Periampullary Tumors Varies over Time

Introduction. Several histopathologic features of periampullary tumors have been shown to be correlated with prognosis. We evaluated their association with mortality at multiple time points. Methods. A retrospective chart review identified 207 patients with periampullary adenocarcinomas who underwent pancreaticoduodenectomy between January 1, 2001 and December 31, 2009. Clinicopathologic features were assessed, and the data were analyzed using univariate and multivariate methods. Results. In univariate analysis, perineural invasion had a strong association with 1-year mortality (OR 3.03, CI 1.42–6.47), and one lymph node (LN) increase in the LN ratio (LNR) equated with a 5-fold increase in mortality. In contrast, LN status (OR 6.42, CI 3.32–12.41) and perineural invasion (OR 5.44, CI 2.81–10.52) had the strongest associations with mortality at 3 years. Using Cox proportional hazards, perineural invasion (HR 2.61, CI 1.77–3.85) and LN status (HR 2.69, CI 1.84–3.95) had robust associations with overall mortality. Recursive partitioning analysis identified LNR as the most important risk factor for mortality at 1 and 3 years. Conclusions. Overall mortality was closely related to the LNR within the first year, while longer follow-up periods demonstrated a stronger association with perineural invasion and overall LN status. Therefore, the current staging for periampullary tumors may need to be updated to include the LNR