3D-printed wound dressings containing a fosmidomycin-derivative prevent Acinetobacter baumannii biofilm formation

Abstract

Acinetobacter baumannii causes a wide range of infections, including wound infections. Multidrug-resistant A. baumannii is a major healthcare concern and the development of novel treatments against these infections is needed. Fosmidomycin is a repurposed antimalarial drug targeting the non-mevalonate pathway, and several derivatives show activity toward A. baumannii. We evaluated the antimicrobial activity of CC366, a fosmidomycin prodrug, against a collection of A. baumannii strains, using various in vitro and in vivo models; emphasis was placed on the evaluation of its anti-biofilm activity. We also developed a 3D-printed wound dressing containing CC366, using melt electrowriting technology. Minimal inhibitory concentrations of CC366 ranged from 1 to 64 μg/mL, and CC366 showed good biofilm inhibitory and moderate biofilm eradicating activity in vitro. CC366 successfully eluted from a 3D-printed dressing, the dressings prevented the formation of A. baumannnii wound biofilms in vitro and reduced A. baumannii infection in an in vivo mouse model.

Keywords: Microbiofilms; Microbiology.

Graphical abstract

Figure 1

Structure of FR900098 and CC366

Figure 2

Anti-biofilm activity of CC366 (16 μg/mL) and CAZ (32 μg/mL) against 10 A. baumannii strains (A) Biofilm inhibition. (B) Biofilm eradication. Bars indicate the mean, dots are individual data points, and error bars represent standard deviation (∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001).

Figure 3

Average survival (n = 139–259 per treatment group) of C. elegans nematodes after infection with A. baumannii (A) A. baumannii strain LMG10520.(B) A. baumannii strain NCTC13423. Infected nematodes were treated with CAZ (solid red line), ATM (dotted red line), or CC366 (solid green line). No significant difference in mortality (p > 0.05) was observed between uninfected controls (solid black line) and infected nematodes treated with CC366. This was also the case for nematodes infected with A. baumannii LMG10520 and treated with CAZ.

Figure 4

Activity of CC366 (32 μg/mL) against A. baumannii strains LMG10520 and NCTC13423 in the artificial dermis model Bars indicate the mean, dots are individual data points, and error bars represent standard deviation (n = 9).

Figure 5

Characterization of PCL-CC366 dressings (A and B) (A) SEM images and (B) picture of a PCL wound dressing of PCL-CC366 5% dressing. (C) Stress-strain tensile test plot. (D) Ultimate Tensile Strength (n = 3). (E and F) (E) Elastic modulus (n = 3) (F) and Fiber diameter (n = 20) of PCL, PCL-CC366 5%, and PCL-CC366 10% 3DP-MEW dressings. Data shown are average, error bars indicate standard deviation.

Figure 6

Average release of CC366 from PCL-CC366 5%, and PCL-CC366 10% 3DP-MEW dressings, expressed as percentage of the initial amount used for pellet preparation Error bars indicate standard deviation, n = 3.

Figure 7

Scanning electron microscopy of the non-loaded PCL dressing and PCL-CC366 5% dressing exposed to 1 mL of 10⁷ CFU of A. baumannii RUH875

Figure 8

CFU counts of dressings and artificial dermis after infection with with A. baumannii RUH875 (A) CFU count of PCL-CC366 5% dressings taken of the dermis infected with A. baumannii RUH875. (B) CFU count of dermis infected with A. baumannii RUH875 after covering with PCL-CC366 5% wound dressings. (C) CFU count of PCL-CC366 10% dressings taken of the dermis infected with A. baumannii RUH875. (D) CFU count of dermis infected with A. baumannii RUH875 after covering with PCL-CC366 10% wound dressings. Lines indicate the mean, dots are individual data points, and error bars represent standard deviation (∗∗∗∗ p < 0.001).

Figure 9

Number of CFU of A. baumannii RUH875 recovered from dressings and tissue biopsies (in vivo tape stripping mouse model) (A) Non-loaded PCL and PCL-CC366 10% dressings. (B) Tissue biopsies. Lines indicate the mean, dots are individual data points, and error bars represent standard deviation (∗∗∗∗ p < 0.0001).