Generating and Reversing Chronic Wounds in Diabetic Mice by Manipulating Wound Redox Parameters

Figure 3

Chronic wounds contain complex antimicrobial-resistant wound microbiota. (a) Bacterial contents of in the swab sample were quantified by measuring the optical densities of stained bacterial films at OD 570 nm (≥0.125 is considered to be biofilm positive—dashed red line). (b) Specific bacterial strain identification shows a dynamic presence of different species with biofilm-forming-capacity. (c) Bacterial prevalence of individual species shows the changing dynamics of the wound microbiota. Quantifying the relative percentage of individual bacterial species demonstrated that Enterococcus sp. and S. epidermidis made up the large majority of the microbial mass with traces of Pseudomonas and E. cloacae at 4 days after IAE treatment. At day 20, the majority of the biomass was composed of biofilm-producing Enterococcus sp. (~40%) and non-biofilm-producing E. cloacae (50%). By day 30, biofilm-producing S. epidermidis disappeared. At day 40, the wounds progressively advanced toward a monospecies infection dominated by E. cloacae and to lesser extent by biofilm-producing Pseudomonas. By day 56, the wounds are exclusively colonized by biofilm-producing E. cloacae. (d) Bacterial burden was evaluated by colony forming unit counts in db/db wounds treated with IAE. (e) The community minimum inhibitory concentration (CMIC) on wound the wound swab samples was examined using the antibiotic amoxicillin. With time, the resistance increased. (f) Skin swabs were collected from C57BL/6 and db/db mice to evaluate their normal skin microbiota. Very similar bacteria were found in the skin of both mouse strains. All data are mean ± SD. for each of the studies unless indicated differently.

(a)

(b)

(c)

(d)

(e)

(f)