Rosenau, F. | Search bioRxiv

bioRxiv2025

Bad bugs, new drugs: The antimicrobial peptide C14R is active against the ESKAPE pathogens

The global rise of antimicrobial resistance among the ESKAPE pathogens represents a major challenge to public health. Here, we report the broad-spectrum antibacterial activity of the synthetic antimicrobial and pore-forming peptide C14R against all six ESKAPE species. Using a radial diffusion assay and resazurin-based viability testing, C14R exhibited potent bactericidal effect with minimum inhibitory concentrations (MICs), defined as the lowest concentration of an antimicrobial agent that completely inhibits visible growth of planktonic microorganisms, ranging from 3.4 g/mL (Enterococcus faecium, vancomycin-resistant) to 45.2 g/mL (Klebsiella quasipneumoniae, ESBL). C14R also inhibited biofilm formation by Gram-positive pathogens, with minimum biofilm inhibitory concentrations (MBICs), referring to the minimal concentration required to prevent the development of biofilms, of 15.0 g/mL (Staphylococcus aureus, MRSA) and 22.0 g/mL (E. faecium, VRE), whereas Gram-negatives biofilms showed higher tolerance. Together, these findings demonstrate that C14R retains high activity against multidrug-resistant ESKAPE strains, highlighting its potential as a lead compound for the development of next-generation antimicrobial drugs to expand the portfolio of available antibiotics and brace health systems against emerging severe infections. Author summaryAntibiotic-resistant infections are a growing threat worldwide. A small group of hospital-associated bacteria is especially problematic because they often evade multiple drugs and cause hard-to-treat infections. In this study, we tested the designed antimicrobial peptide C14R as a novel and effective way to fight these bacteria. Peptides are short protein fragments with the ability to puncture and disrupt microbial membranes. We evaluated C14R against six hospital related priority species (so called ESKAPE pathogens) and measured its ability to stop growth and to limit biofilm formation. C14R killed every species we tested and reduced biofilm of two bacteria. Our findings identify C14R as a promising lead for new treatments, particularly for difficult infections and those involving biofilms.

microbiology↗

bioRxiv2025

gFET-based aptasensors technology allows sensitive and specific quantification of the ESKAPE pathogens

The rapid rise of antimicrobial resistance among the ESKAPE pathogens, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp., requires diagnostic technologies capable of fast, simplified and sensitive microbial detection. Conventional culture-based diagnostics remain too time-consuming to guide early therapeutic interventions. Here, we present a graphene field-effect transistor (gFET) aptasensor platform enabling rapid, label-free and highly sensitive quantification of all six ESKAPE pathogens. Each gFET device was functionalized with a specific DNA aptamer selected from literature sources and immobilized via a mixed pyrene-based linker strategy on reduced graphene oxide (rGO). Exposure of the functionalized sensors to logarithmically diluted bacterial suspensions (10-105 CFU mL-) produced characteristic and concentration-dependent shifts in source-drain current ({Delta}IDS). For all pathogen-specific aptamers, {Delta}IDS correlated linearly with bacterial load (R2 = 0.90-1.00), while non-target bacteria generated only low-level, unspecific fluctuations. Limits of detection ranged from 10 to 1000 bacterial cells depending on the aptamer. Together, these results demonstrate that aptamer-functionalized rGO-FETs provide a robust, scalable and highly specific electronic biosensing architecture capable of distinguishing clinically relevant multidrug-resistant pathogens with excellent analytical performance. Author summaryAntimicrobial-resistant bacteria pose a growing threat to global health, especially the so-called ESKAPE pathogens, which frequently cause hospital-acquired infections and are increasingly difficult to treat. Current diagnostic methods can take several days, delaying the start of effective therapy. In our work, we developed a fast and highly sensitive biosensor that uses electrically conductive GO and short DNA molecules, called aptamers, to recognize specific bacteria. When a pathogen binds to its matching aptamer on the sensor surface, the electrical signal of the graphene changes in a measurable way. We tested ESKAPE species and showed that all of the investigated aptamers detect only their intended bacterial targets, even at very low concentrations. Importantly, the sensors respond within minutes and do not require any labelling or complex sample preparation. Our technology demonstrates how graphene-based aptasensors can support rapid and accurate detection of dangerous bacterial pathogens and could ultimately help clinicians make faster decisions in treating infections.

microbiology↗