Antimicrobial resistance is one of the world’s most worrying public health challenges. Multidrug-resistant (MDR) Gram-negative bacteria are increasingly rendering even last-line antibiotics ineffective, significantly increasing mortality rates. Polymyxins are a type of antibiotic and one of the few treatment options available for serious infections caused by resistant bacteria. Escherichia coli. However, its widespread use is limited by severe side effects such as renal and neurotoxicity.
Capitalizing on this gap, researchers have now developed an innovative strategy where bacteria are more susceptible to these antibiotics, allowing doctors to use lower doses safely without sacrificing efficacy. This innovative approach shifts the focus from antibiotic-centered therapies to bacterial control-centered therapies, making bacteria more susceptible to antibiotics by promoting membrane gateways that facilitate antibiotic uptake.
The research team is led by Professor Kim Kwang-sung from the Department of Chemistry and Functional Materials Research Institute at Busan University, South Korea. The study was made available online on April 22, 2026, and was published in volume 87 of the journal. Latest information on drug resistance July 1, 2026.
”While the development of new antibiotics has not kept pace with bacterial evolution, maximizing the effectiveness of existing resources will be a key strategy to fill therapeutic gaps in clinical practice.says Professor Kim.
Rather than design another antibiotic that directly kills bacteria, the researchers identified a naturally occurring peptide called TimP, which is encoded by the bacteria’s small noncoding RNA (sRNA) RyfA and promotes the remodeling of the bacteria’s own outer membrane. This remodeling creates an opening that allows polymyxins to more effectively penetrate the bacterial envelope.
The research team screened 91 bacterial sRNAs to identify molecules that can increase susceptibility to polymyxins and identified RyfA, whose peptide TimP plays a role in dramatically increasing antibiotic susceptibility. structure prediction and in vitro In our validation, we showed that TimP binds to an outer membrane protein called porin LamB, causing extensive changes in the bacterial envelope. These changes include increased membrane permeability, increased production of reactive oxygen species, and increased release of extracellular vesicles.
The researchers then engineered extracellular vesicles (EVs) carrying both TimP and polymyxin B (PMB) to create a targeted delivery platform called PMB@TimP EV. The vesicles functioned as a “Trojan horse drug delivery system,” delivering the antibiotic directly to the bacteria while facilitating the drug’s penetration into the bacterial membrane.
Further analysis showed that PMB@TimP EVs had enhanced bacterial killing compared to free PMB, remained stable over a wider pH range, and had minimal toxicity to mammalian cells. In a mouse model of sepsis caused by MDR Escherichia colithe engineered vesicles improved survival at doses where free PMB conferred no protection against infection. Additional safety studies showed no abnormal accumulation of treatment in major organs, while inflammatory markers and liver enzymes remained within normal physiological ranges.
The researchers also found that LamB, a bacterial outer membrane protein required for TimP activity, is conserved. Typhimurium. According to the research team, this suggests that the platform could be adapted to combat a wider range of multidrug-resistant Gram-negative bacteria. Escherichia coli.
”PMB@TimP EV It can serve as a powerful adjunctive therapy for patients suffering from sepsis, pneumonia, and urinary tract infections caused by MDR Gram-negative bacteria and can significantly improve recovery rates. ” Professor Kim says.
Although the findings are promising, the researchers stress that the study has so far been demonstrated in a murine model. Further research will be needed before the platform can be tested in human clinical trials, including investigating long-term safety, manufacturing, and efficacy against a broader range of resistant infections.
”Within 5-10 years, this platform could be integrated into the standard for combating MDR pathogens. This will ultimately reduce antibiotic overprescription and contribute to a more sustainable healthcare system.” said Professor Kim.
If future clinical studies confirm these findings, this platform has the potential to extend the lifespan of existing antibiotics, reduce the need for high-dose polymyxin therapy, and provide clinicians with new strategies to treat life-threatening infections caused by multidrug-resistant Gram-negative bacteria.
sauce:
Busan University
Reference magazines:
Cho, H. Others. (2026). The sRNA-encoded peptide TimP rewires the E. coli envelope via LamB and sensitizes the bacteria to polymyxins. Latest information on drug resistance. DOI: 10.1016/j.drup.2026.101406. https://www.sciencedirect.com/science/article/abs/pii/S1368764626000579?via%3Dihub
