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Page 4 of 16 Tejiram et al. Plast Aesthet Res. 2025;12:9 https://dx.doi.org/10.20517/2347-9264.2024.109

METHODS
Study protocol, inclusion and exclusion criteria
The protocol was approved by Medstar Health Research Institute’s Institutional Review Board (Protocol
#2017-186). This single-site, randomized pilot study was conducted at MedStar Washington Hospital
Center (MWHC) from 2018-2020. During this period, 31 patients were enrolled. Patients were randomized
into two groups and blinded to their intervention status. Randomization was achieved using a computerized
random number generator. Patients and assessors remained blinded throughout the study. Cefazolin is a
common preoperative antibiotic used due to its coverage of common skin flora organisms, wide availability,
and ease of administration within the perioperative setting. This antibiotic was chosen for the study due to
its availability at our institution. Preoperative antibiotic administration was chosen over perioperative
antibiotic use, where antibiotics could be administered following operative intervention for better
experimental control. One group (ABX) received a single dose of weight-based cefazolin upon induction of
anesthesia. Patients weighing less than 120 kg received 2 g of cefazolin intravenously. Patients over 120 kg
received 3 g of cefazolin. Patients were re-dosed every 4 h if they remained in the operating room. The non-
antibiotics group (no-ABX) received the standard of care at this institution, which does not include
perioperative antibiotics.

For all eligible patients included, informed consent was obtained before study participation. Subjects
included in the study were 18 years or older at the time of consent and presented to our institution within
48 h after sustaining a thermal injury. Patients with a TBSA of ≤ 10% who were anticipated to require a
single grafting procedure were considered eligible. Patients with TBSA burn sizes above this often have
earlier and more complications compared to lower-sized TBSA injuries that may include earlier infections
of various sources and earlier antibiotic administration. A smaller TBSA burn injury allowed for better
experimental control over the administration of a single antibiotic dose, with closely monitored follow-up
and minimization of complications related to the injury. Patients were excluded from the study if they
received antibiotics within 30 days prior to admission, already had burn wound cellulitis or an infection
diagnosed preoperatively, or an infection discovered during burn excision. Incarcerated individuals and/or
a positive pregnancy test in females were also excluded from the study.

All excision and grafting procedures were performed early, within approximately 72 to 96 h after the burn
injury. This minimized the risk of microbial colonization over time, which could have affected clinical
outcomes or microbiome analysis. Following burn wound excision, an attending surgeon assessed the
wound bed and decided on either porcine xenograft or autograft. Any burn that was anticipated to require
[25]
autografting but was treated with an interval xenograft was still included in the study . Split-thickness skin
grafts were obtained using a dermatome (Humeca, Woodstock, GA) at a depth of 0.008-0.012 and then
meshed at expansion ratios of 1:1, 2:1, or 3:1, depending on the size and location of the wound (Brennan
Medical, St. Paul, MN). Petroleum jelly-impregnated non-adherent dressings were then applied. All
autografts were dressed with a negative pressure wound therapy device (KCI, San Antonio, TX) set to
125 mm Hg, continuous pressure with medium intensity or a compressive dressing comprised of layers of
gauze bandage roll and ultimately covered by a uniform layer of elastic wrap. Porcine xenograft was secured
and dressed in a similar manner when placed. All dressings were removed on postoperative day 3. At the
end of the study in 2020, porcine xenograft became unavailable across the nation, and therefore, one patient
in each group received a skin substitute instead of a porcine xenograft (Polymedics, Woodstock, GA).
Donor sites were dressed with an antimicrobial foam exudate transfer dressing (Molnlycke, Peachtree
Corners, GA). This primary dressing was then dressed with gauze bandage roll dressing and elastic wraps to
create a compressive dressing over the donor sites.