Star-Shaped Polymers Kill Antibiotic Resistant Bacteria

A new study suggests that structurally nanoengineered antimicrobial peptide polymers (SNAPPs) could provide a low-cost and effective antimicrobial agent against multidrug resistant (MDR) bacteria.

Developed by researchers at the University of Melbourne (UNIMELB; Parkville, Australia), the star-shaped SNAPP is extremely effective at killing Gram-negative bacteria while being non-toxic to the body’s own cells, thanks to its unique antimicrobial activity. SNAPPs induce cell death by a multimodal mechanism that combines outer membrane destabilization, unregulated ion movement across the cytoplasmic membrane, and induction of the apoptotic-like death pathway.

The SNAPPs exhibited sub-μM activity against all Gram-negative bacteria tested, including the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter, Pseudomonas aeruginosa and Enterobacter) pathogens and other colistin-resistant and MDR (CMDR) pathogens, while demonstrating low toxicity. In addition, the researchers did not observe any resistance acquisition by A. baumannii (including the CMDR strain) to SNAPPs. The study was published on September 12, 2016, in Nature Microbiology.

“It is estimated that the rise of superbugs will cause up to ten million deaths a year by 2050. In addition, there have only been one or two new antibiotics developed in the last 30 years,” concluded senior author Professor Greg Qiao, PhD, of the department of chemical and biomolecular engineering, and colleagues. “Overall, SNAPPs show great promise as low-cost and effective antimicrobial agents, and may represent a weapon in combating the growing threat of MDR Gram-negative bacteria.”

Antimicrobial polymers are engineered to mimic peptides used by the immune systems of living things to kill bacteria. Typically, they are produced by attaching or inserting an active antimicrobial agent onto a polymer backbone via an alkyl or acetyl linker. The use of antimicrobial polymers may enhance the efficiency and selectivity of common antimicrobial agents, while decreasing associated environmental hazards since they are generally nonvolatile and chemically stable.

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