Metabolite-Mediated Bacterial Antibiotic Resistance Revealed by Surface-Enhanced Raman Spectroscopy

Abstract

A prompt on-site, real-time method to detect bacterial antibiotic resistance is crucial for controlling the spread of resistance. Herein, we report the use of surface-enhanced Raman spectroscopy (SERS) for the monitoring of bioactive metabolites produced by ampicillin-resistant Pseudomonas aeruginosa strains and identification of mechanisms underlying antibiotic resistance. The results indicate that the blue-green pigment pyocyanin (PYO) dominates the metabolite signals and is significantly enhanced upon exposure to subminimal inhibitory concentrations of ampicillin. PYO accumulates during exponential growth and subsequently either diffuses into the culture medium or is consumed in response to nutrient deprivation. The SERS spectra further reveal that the production of some intermediate substances such as polysaccharides and amino acids is minimally impacted and that nutrient consumption remains consistent. Moreover, the intensity changes and peak shifts observed in the SERS spectra of non-PYO-producing ampicillin-susceptible Escherichia coli demonstrate that exogenously added PYO enhances E. coli tolerance to ampicillin to some extent. These results indicate that PYO mediates antibiotic resistance not only in the parent species but also in cocultured bacterial strains. The metabolic SERS signal provides new insight regarding antibiotic resistance with promising applications for both environmental monitoring and rapid clinical detection.

Rapid identification of bloodstream infection pathogens and drug resistance using Raman spectroscopy enhanced by convolutional neural networks

“… Wang X. et al (2023) demonstrated the detection of E. coli using an aptamer-modified Au@macroporous magnetic silica photonic microsphere (MMSPM) 3D SERS-activated substrate. Concurrent efforts focused on monitoring bioactive metabolites secreted by ampicillin-resistant P. aeruginosa strains, revealing resistance mediated by the pigment pyoverdine (PYO) ( Wang and Vikesland, 2023 ). To mitigate the impact of silver nanoparticle size and aggregation on Raman spectroscopy signals, we employ a series of strategies, including precise control over synthesis conditions for uniform particle size, utilization of stabilizing agents to prevent aggregation, ultrasonication for temporary dispersion, and centrifugation to remove aggregates.…”

Deciphering biomolecular complexities: the indispensable role of surface-enhanced Raman spectroscopy in modern bioanalytical research

“…Vikesland and colleagues employed SERS for discerning bioactive metabolites in ampicillin-resistant Pseudomonas aeruginosa strains, further illuminating antibiotic resistance mechanisms. 91 Their findings underscored the dominant role of the pigment pyocyanin (PYO), especially under subminimal inhibitory concentrations of ampicillin, offering insights into antibiotic resistance not just within the parent strain but also in cocultured bacterial strains (illustrated in Fig. 10D).…”

“…Transitioning to bioactive small molecular entities, which encompass hormones, 88 neurotransmitters, 89 vitamins, 56,90 and antibiotics, 91 their pivotal roles within biological systems are undeniable. They're intricately involved in myriad processes from cellular proliferation to neural transmission.…”

“…Such insights not only enrich our understanding of foundational life processes but also augur well for pharmaceutical innovation, disease diagnostics, and therapeutic advancements. 87,91 3.4. Probing cellular dynamics and organelle functionality via SERS SERS extends beyond mere analysis of discrete biomolecules, holding promise for real-time surveillance of cells and their constituent organelles.…”

“…Such insights not only enrich our understanding of foundational life processes but also augur well for pharmaceutical innovation, disease diagnostics, and therapeutic advancements. 87,91…”