LSPR-Based Biosensing Enables the Detection of Antimicrobial Resistance Genes

The development of rapid, simple, and accurate bioassays for the detection of nucleic acids has received increasing demand in recent years. Here, localized surface plasmon resonance (LSPR) spectroscopy for the detection of an antimicrobial resistance gene, sulfhydryl variable beta-lactamase (blaSHV), which confers resistance against a broad spectrum of beta-lactam antibiotics is used. By performing limit of detection experiments, a 23 nucleotide (nt) long deoxyribonucleic acid (DNA) sequence down to 25 nm was detected, whereby the signal intensity is inversely correlated with sequence length (23, 43, 63, and 100 nt). In addition to endpoint measurements of hybridization events, the setup also allowed to monitor the hybridization events in real-time, and consequently enabled to extract kinetic parameters of the studied binding reaction. Performing LSPR measurements using single nucleotide polymorphism (SNP) variants of blaSHV revealed that these sequences can be distinguished from the fully complementary sequence. The possibility to distinguish such sequences is of utmost importance in clinical environments, as it allows to identify mutations essential for enzyme function and thus, is crucial for the correct treatment with antibiotics. Taken together, this system provides a robust, label-free, and cost-efficient analytical tool for the detection of nucleic acids and will enable the surveillance of antimicrobial resistance determinants.

Automated summary

The need for rapid, simple, and accurate bioassays for nucleic acid detection has increased in recent years. This study utilized localized surface plasmon resonance (LSPR) spectroscopy to detect the antimicrobial resistance gene, sulfhydryl variable beta-lactamase (blaSHV), which confers resistance against a broad spectrum of beta-lactam antibiotics. The system was able to detect a 23 nucleotide DNA sequence at a limit of 25 nm, with signal intensity inversely correlated to sequence length. It was also capable of real-time monitoring and distinguishing single nucleotide polymorphism (SNP) variants of blaSHV.