Rapid and colorimetric assay for the detection of S. pneumoniae based on hydrogen peroxide release and analysis using
Cagla Celik Yoldas1, Nimet Temur2, Nilay Ildiz3
1Department of Analytical Chemistry, Faculty of Pharmacy, Harran University, 63050, Sanliurfa, Türkiye. caglacelik@harran.edu.tr.
Abstract:
Although Streptococcus pneumoniae (S. pneumoniae) is routinely identified using various clinical methods, most existing techniques are complicated, time-consuming, and require expensive equipment. Consequently, there is a critical need for rapid, sensitive, and economical detection methods. Herein, we report a rationally designed colorimetric assay incorporating biocompatible anthocyanins for the rapid detection of S. pneumoniae via the naked eye and image processing software. Unlike conventional anthocyanin-based assays that rely on pH-dependent color changes, our approach uses anthocyanins as oxidative degradation probes rather than pH indicators. The detection mechanism relies on the oxidative degradation of anthocyanins by hydrogen peroxide (H2O2), a key virulence factor secreted by S. pneumoniae, which induces a distinct color shift to gray. We systematically evaluated the performance of this assay in various matrices, including growth medium, saline solution, and artificial cerebrospinal fluid (aCSF). Bacterial suspensions of 1.0 and 1.5 McFarland were colorimetrically detected within 90 and 30 minutes, respectively, through naked-eye observation and Delta-E analysis. This study demonstrates a highly stable, cost-effective, and easy-to-prepare diagnostic tool that offers significant advantages over traditional methods for point-of-care testing.
Insights
A new colorimetric assay uses anthocyanins to rapidly detect Streptococcus pneumoniae (S. pneumoniae) by observing a color change. This cost-effective method offers a sensitive alternative for quick point-of-care diagnostics.
Area of Science:
- Biochemistry
- Microbiology
- Analytical Chemistry
Background:
- Current Streptococcus pneumoniae (S. pneumoniae) detection methods are often complex, slow, and expensive.
- There is a significant need for rapid, sensitive, and affordable diagnostic tools for S. pneumoniae.
Purpose of the Study:
- To develop a novel, rapid, and economical colorimetric assay for S. pneumoniae detection.
- To utilize anthocyanins as oxidative degradation probes for detecting a key S. pneumoniae virulence factor.
Main Methods:
- A colorimetric assay was designed using biocompatible anthocyanins as probes.
- The assay detects hydrogen peroxide (H2O2), a virulence factor secreted by S. pneumoniae, via anthocyanin oxidative degradation.
- Detection was validated using naked-eye observation and Delta-E analysis in various matrices (growth medium, saline, aCSF).
Main Results:
- The assay detected S. pneumoniae via a distinct gray color shift caused by H2O2-induced anthocyanin degradation.
- Bacterial suspensions (1.0 and 1.5 McFarland) were detected in 90 and 30 minutes, respectively.
- The assay demonstrated high stability and effectiveness across different testing environments.
Conclusions:
- A cost-effective, rapid, and sensitive colorimetric assay for S. pneumoniae detection was successfully developed.
- This assay offers significant advantages over traditional methods for point-of-care testing.
- The use of anthocyanins as oxidative probes provides a novel approach for bacterial diagnostics.
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