Antimicrobial activity in vitro
The antimicrobial activity of desiccating agent A was evaluated against a dense inoculum (1012 CFU/mL) that contained a broad spectrum of pathogens, including gram-negative bacteria (E coli, P aeruginosa, T forsythia, P gingivalis), gram-positive bacteria (S aureus, E hirae), and fungi (C albicans). The 50 µL spot of desiccating agent A added to the center of the pool-inoculated plates had significantly reduced growth, with an inhibition ring of 54 mm ± 5 mm diameter at 24 hours (Figure 1).
Case series
Ten patients with diabetic leg ulcers (n = 2), leg ulcers associated with venous insufficiency (n = 5), vasculitic leg ulcers (n = 1), revascularized ischemic leg ulcers (n = 1), or posttraumatic leg ulcers (n = 1) were enrolled in this prospective observational trial. The ischemic leg ulcer on the revascularized leg was not healing at the time of enrollment despite successful revascularization. The demographics of the patients and their wound characteristics are shown in Table 1. The median age of the 10 patients (5 females, 5 males) was 72.5 years (range, 50–90 years). The pedidial artery pulses ranged from completely normal (n = 5) to present and strongly reduced (n = 2) (Table 1). The duration of the ulcers ranged from 6 weeks to 52 weeks, with a median of 10 weeks and interquartile range (IQR) of 6 weeks and 24 weeks (Table 1). The median wound bed area was 64 cm2 (IQR: 20.5 cm2, 110 cm2). The chronic wounds of all patients contained slough over most of the wound bed. The most common prior wound treatments included iodopovidone-soaked gauzes (4/10 patients), silver-containing dressings (4/10 patients), and gentamicin plus betamethasone cream (Table 1). All patients were followed for at least 6 months after treatment with desiccating agent A.
Immediate effects of desiccating agent A
There were 2 different types of reactions after desiccating agent A application to a wound bed. In 4 cases (eg, Figure 2; case 2), the material present on the wound bed instantly coagulated, and the dried layer was easily, and mostly, removed from the wound bed with saline rinse followed by wiping with a dry gauze. In these cases, desiccating agent A treatment removed the wound material often described as slough and had exposed vital tissue. In the authors’ experience, this effect was common in chronic lesions with low-grade inflammation and minimal infection.
The application of desiccating agent A in 6 cases resulted in coagulation and contraction of the material on the wound bed, but the material did not detach with simple rinsing (Figure 3, Figure 4, Figure 5, and Figure 6; cases 3, 4, 7, and 9, respectively). Spot bleeding had appeared throughout the desiccated material in some cases; bleeding was easily stopped with gentle pressure. The authors’ impression was that this effect was common in wound beds with robust infections and high-grade inflammation. The surrounding skin in all cases was simply left degreased by desiccating agent A treatment and did not show signs of redness, nodules, or vesicles.
Late effects of desiccating agent A
The 1-week visit of 4 patients with wounds left clean by desiccating agent A revealed the presence of mild secretions that were easily removed with saline rinse. These patients did not need or receive an extra application of desiccating agent A. These wounds rapidly evolved to complete granulation on the wound bed. At 6 weeks after desiccating agent A treatment, the status of these 4 wounds was judged to be in the healing phase.
In the 6 wounds in which the desiccated material remained attached to the wound bed, at the 1-week visit, the desiccated material had completely or partially resolved. This effect may be due to reactivation of macrophages. The 6 wounds were judged to be progressing in the healing process at the 6-week endpoint.
In all patients, the desiccated material in the treated wound bed was progressively replaced by granulation tissue. As expected, the wound bed area at 100% full granulation was the same (n = 5) or modestly reduced (n = 5) in comparison to the basal wound bed area (Table 1). Median time to reach granulation was 20.5 days (range, 7–78 days) (Table 1). Interestingly, the median time for males to reach full granulation was shorter (median, 14 days; range, 7–26 days) than that of females (median, 45 days; range, 9–78 days). None of these patients needed an additional application of desiccating agent A; thus, no additional applications were applied.
Side effects and adverse events
Patient-reported transient pain was the only adverse events, and no nodules, welts, blisters, or vesicles were reported. After desiccating agent A application, the patients without concomitant sensory neuropathy (n = 8) experienced a burning sensation with a median pain score of 2.5 (IQR: 2, 5) (Table 2). The pain persisted for a median of 5 minutes (range, 1–180 minutes) (Table 2). To uncover if a large wound bed area was possibly associated with greater pain intensity, the authors compared the pain reported by the 4 patients who had wound-bed areas greater than or equal to 100 cm2 (range, 100–140 cm2). The observations that 2 cases (Cases 7, 9) had reported pain intensity of 7 for 180 minutes whereas 2 cases (Cases 1, 4) reported pain intensity of 2 for 5 and 15 minutes suggested that wound size was not the major determining factor. No association was detected between the wound bed size of the 8 cases and pain.