Therapeutic Potential of an Azithromycin-Colistin Combination against XDR K. pneumoniae in a 3D Collagen-Based In Vitro Wound Model of a Biofilm Infection

Abstract

A therapeutic combination of azithromycin (AZM) and colistin methanesulfonate (CMS) was shown to be effective against both non-PDR and PDR Klebsiella pneumoniae biofilms in vitro. These anti-biofilm effects, however, may not correlate with effects observed in standard plate assays, nor will they representative of in vivo therapeutic action. After all, biofilm-associated infection processes are also impacted by the presence of wound bed components, such as host cells or wound fluids, which can all affect the antibiotic effectiveness. Therefore, an in vitro wound model of biofilm infection which partially mimics the complex microenvironment of infected wounds was developed to investigate the therapeutic potential of an AZM-CMS combination against XDR K. pneumoniae isolates. The model consists of a 3D collagen sponge-like scaffold seeded with HEK293 cells submerged in a fluid milieu mimicking the wound bed exudate. Media that were tested were all based on different strengths of Dulbecco’s modified Eagles/high glucose medium supplemented with fetal bovine serum, and/or Bacto Proteose peptone. Use of this model confirmed AZM to be a highly effective antibiofilm component, when applied alone or in combination with CMS, whereas CMS alone had little antibacterial effectiveness or even stimulated biofilm development. The wound model proposed here proves therefore, to be an effective aid in the study of drug combinations under realistic conditions.

Case report: Azithromycin-meropenem combination therapy as a low-cost approach to combat PDR gram-negative infections of war wounds in Ukraine

“…Until transportation to Kyiv City Clinical Hospital No 6 and within the first 8 days, only MDR gram-negative isolates were detected. It is important to emphasize that all these four isolates were sensitive to tigecycline, and they hypothetically may be still sensitive to colistin, as colistin-resistance is still not so often encountered in Ukrainian hospital isolates, as demonstrated before (16) or as demonstrated by other authors (17). However, despite this rational combined antimicrobial therapy with colistin and tigecycline, the condition of the patient decreased: he had hypothermia, anemia, underwent two blood transfusions, his bilirubin level was increased and PCT varied from 3.247 to 1.698 ng/mL (Figure 3).…”

“…The newly suggested therapy was focused on anti-biofilm therapy and included azithromycin which was effective against gram-negative XDR/PDR Ukrainian Hospital Isolates as shown before ( 16 , 18 ). The combination therapy with azithromycin and meropenem was suggested based on own previous experimental and clinical data which confirmed that both antibiotics demonstrated a strong synergistic effect in vivo against diverse gram-negative hospital isolates.…”

Effects of transplantation of preconditioned mesenchymal stem cells seeded on a biomimetic 3D scaffold

“…In the present work, we used the porous 3D collagen scaffolds, developed using freezedrying technique described in our previous study [8]. The technique allowed obtaining the scaffolds that had an average pore diameter of 117±57 µm.…”

“…Collagen scaffold preparation. The porous collagen scaffolds were produced from a solution of bovine atelocollagen in acetic acid using a freeze-drying technique described previously [8]. Briefly, the solution of type I atelo collagen, isolated from a bovine tendon, of 20 mg/mL in 0.5 M acetic acid was prepared.…”

Relationship between biofilm formation and antibiotic resistance of Klebsiella pneumoniae and updates on antibiofilm therapeutic strategies

“…The combination of 8 µg/mL SPR741, 16 µg/mL clarithromycin, and 16 µg/mL erythromycin was found to be the most potent against pre-formed biofilms (48 hours). Moshynets et al investigated the therapeutic potential of AZM-CMS combination against XDR K. pneumoniae isolates using 3D Collagen-Based in vitro wound model of biofilm infection, and the results confirmed AZM to be an effective antibiofilm drug used either alone or in combination with CMS (Moshynets et al, 2023).…”