Eradicating Biofilms of Carbapenem‐Resistant Enterobacteriaceae by Simultaneously Dispersing the Biomass and Killing Planktonic Bacteria with PEGylated Branched Polyethyleneimine

Abstract

Carbapenem‐resistant Enterobacteriaceae (CRE) are emerging pathogens that cause variety of severe infections. CRE evade antibiotic treatments because these bacteria produce enzymes that degrade a wide range of antibiotics including carbapenems and β‐lactams. The formation of biofilms aggravates CRE infections, especially in a wound environment. These difficulties lead to persistent infection and non‐healing wounds. This creates the need for new compounds to overcome CRE antimicrobial resistance and disrupt biofilms. Recent studies in our lab show that 600 Da branched polyethyleneimine (BPEI) and its derivative PEG350‐BPEI can overcome antimicrobial resistance and eradicate biofilms in methicillin‐resistant S. aureus, methicillin‐resistant S. epidermidis, P. aeruginosa, and E. coli. In this study, the ability of 600 Da BPEI and PEG350‐BPEI to eradicate carbapenem‐resistant Enterobacteriaceae bacteria and their biofilms is demonstrated. We show that both BPEI and PEG350‐BPEI have anti‐biofilm efficacy against CRE strains expressing Klebsiella pneumoniae carbapenemases (KPCs) and metallo‐β‐lactamases (MBLs), such as New Delhi MBL (NDM‐1). Furthermore, our results illustrate that BPEI affects planktonic CRE bacteria by increasing bacterial length and width from the inability to proceed with normal cell division processes. These data demonstrate the multi‐functional properties of 600 Da BPEI and PEG350‐BPEI to reduce biofilm formation and mitigate virulence in carbapenem‐resistant Enterobacteriaceae.

Neutralizing Staphylococcus aureus PAMPs that Trigger Cytokine Release from THP-1 Monocytes

“…An added benefit to killing bacteria is reducing biofilm formation, which impedes the healing process and enhances bacterial resistance against antibiotics and immune defenses. 33 Lastly, we assessed the impact of polymyxin B, an FDAapproved cationic antibiotic known to possess certain antiinflammatory properties. Polymyxin B, a cationic polypeptide, contains five primary amine groups that, at physiological pH, are protonated and bear a positive charge.…”

“…Moreover, BPEI and PEG-BPEI potentiators possess an additional advantage in their ability to disrupt biofilms formed by Staphylococci, P. aeruginosa, and carbapenem-resistant Enterobacteriaceae bacteria expressing KPC and NDM-1. − …”

“…Likewise, intact bacterial cells inhibit tissue regeneration as they release toxins within wounds that can damage tissue cells and hinder their proliferation and migration capacities. , Therefore, killing these cells is also important. An added benefit to killing bacteria is reducing biofilm formation, which impedes the healing process and enhances bacterial resistance against antibiotics and immune defenses …”

“…We have previously identified low molecular weight 600 Da branched polyethylenimine (600 Da BPEI) (Figure top) as a broad-spectrum antibiotic potentiator that can overcome antibiotic resistance and eradicate biofilms of multidrug-resistant strains of Gram-positive and Gram-negative bacteria including methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and carbapenem-resistant Enterobacteriaceae. − ,− ,− However, the toxicity concerns arising from the presence of primary amines 600 Da BPEI are significant and need to be addressed. The in vivo toxicity concerns are resolved by covalently conjugating a low-molecular-weight polyethylene glycol (350 MW PEG) moiety to 600 Da BPEI, resulting in PEG-BPEI (Figure bottom). ,− Additionally, we have shown that the PEGylated derivative possesses the potentiator characteristics of BPEI against the MDR strains and their biofilms. ,− Regardless of the BPEI ability to facilitate the uptake of drugs and lower drug influx barriers as an antibiotic potentiator against bacterial biofilms and planktonic cells, therapeutic benefits of 600 Da BPEI and PEG-BPEI can be expanded.…”

“… − ,− ,− However, the toxicity concerns arising from the presence of primary amines 600 Da BPEI are significant and need to be addressed. The in vivo toxicity concerns are resolved by covalently conjugating a low-molecular-weight polyethylene glycol (350 MW PEG) moiety to 600 Da BPEI, resulting in PEG-BPEI (Figure bottom). ,− Additionally, we have shown that the PEGylated derivative possesses the potentiator characteristics of BPEI against the MDR strains and their biofilms. ,− Regardless of the BPEI ability to facilitate the uptake of drugs and lower drug influx barriers as an antibiotic potentiator against bacterial biofilms and planktonic cells, therapeutic benefits of 600 Da BPEI and PEG-BPEI can be expanded. In this work, we continue to investigate 600 Da BPEI and its PEGylated derivative as anti-PAMP molecules to help mitigate the overproduction of inflammatory response.…”