Biologically Compatible Lignin Solution Used to Overcome Bacterial Resistance to Antibiotics

Solvates Lignin in a Biocompatible Solution Enabling Greater Susceptibility to Beta-Lactam Antibiotics

This aqueous lignin has potential as a low-cost antibacterial as well as an adjuvant to overcome bacterial resistance to β-lactam antibiotics. Lignin is a biopolymer found in plant cell walls and is a byproduct produced in large quantities by paper and pulping industries and renewable fuel biorefineries. Although lignin has many potential industrial uses, application to living systems has been very limited because the solvents required to solubilize lignin are incompatible with living cells. Researchers at the University of Florida have identified aqueous buffers, known as Good’s buffers, originally designed for buffering cell cultures, as capable of solvating lignin, which results in a sterile, concentrated lignin nanoparticle solution. This has allowed more in-depth investigation of lignin’s antibacterial activity and resulted in the unexpected finding that lignin restores the sensitivity of antibiotic-resistant Staphylococcus aureus to beta-lactam antibiotics. Bacterial antibiotic drug resistance has been a growing public health crisis for decades and will continue to worsen unless it is addressed. Many strains of S. aureus, such as methicillin-resistant S. aureus (MRSA), are insensitive to treatment with commonly prescribed β-lactam antibiotics. Researchers have demonstrated that strains of S. aureus, including MRSA, possessing resistance to penicillin, ampicillin, and oxacillin (a methicillin derivative) were rendered susceptible to these antibiotics in the presence of lignin, potentially providing a new avenue for treatment of β-lactam-resistant S. aureus infections.

Application

Aqueous lignin as a low-cost antibacterial as well as an adjuvant to overcome bacterial resistance to β-lactam antibiotics

Advantages

• Solubilized lignin represents a low-cost, readily available and easily prepared reagent for biological, medical, and food packaging applications
• Combined with beta-lactam class antibiotics, overcoming bacterial resistance to treat infections
• Induces or restores antibiotic sensitivity in resilient bacteria such as S. aureus, including MRSA, offering a possible method of co-treating infections from β-lactam-resistant bacteria

Technology

Zwitterionic buffers known as Good’s buffers can be used to solvate lignin at biological pH values. The lignin solution has antibacterial properties in its own right, but unexpectedly and very importantly, it restores β-lactam susceptibility to resistant strains of S. aureus such as MRSA and reduces the concentration of antibiotic required to kill otherwise susceptible strains.