UAMS-led research team develops new way to fight antibiotic-resistant infections

A research team led by University of Arkansas for Medical Sciences (UAMS) microbiologist Mark Smeltzer and University of Arkansas chemist Jingyi Chen has developed an alternative therapeutic approach to fighting antibiotic-resistant infections.

The new method uses a targeted nanodrug consisting of gold nano “cages” loaded with antibiotic that when irradiated with lasers, converts the irradiation to heat which generates a “photothermal effect” capable of killing bacteria and at the same time releases the antibiotic, thus resulting in a synergistic therapeutic effect. Nanoparticles are extremely tiny materials, containing just a few atoms.

This work was recently published in ACS Infectious Diseases, a publication of the American Chemical Society (ACS).

“We believe that this approach could facilitate the effective treatment of infections caused by antibiotic-resistant bacteria including those associated with bacterial biofilms, which are involved in a wide variety of bacterial infections,” said Chen, assistant professor in the Department of Chemistry and Biochemistry in the J. William Fulbright College of Arts and Sciences.

Microbial resistance to antibiotics has become a growing public health concern in hospitals and the community at large. The Infectious Diseases Society of America has designated six bacterial species as “ESKAPE pathogens” –  Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species– owing to decreasing availability of antibiotics that are active against these species.

The team used Staphylococcus aureus to demonstrate the potency of their nanodrug. The combination of achieving a photothermal effect and controlled release of antibiotics directly at the site of infection was achieved by laser irradiation at levels within the current safety standard for use in humans.

The therapeutic effects were validated using planktonic bacterial cultures, which are bacterial cells that are free-floating rather than contained with a biofilm, of both methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MRSA) strains. However, the method was subsequently shown to be effective even in the context of an intrinsically resistant biofilm.

Additionally, Smeltzer said, “The even better news is that the technology we developed would be readily adaptable to other bacterial pathogens that cause such infections, including the other ESKAPE pathogens.”