Iridium oxide-based biosensors: A novel method for ESBL detection and quantification
Introduction: The emergence of Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae poses a significant therapeutic challenge. Current antimicrobial susceptibility testing methods have limitations in detecting and characterising ESBL pathogens. With broad-spectrum beta-lactam use cre...
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Elsevier
2025-03-01
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| Series: | International Journal of Infectious Diseases |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1201971224007197 |
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| author | Miss Jennifer Lawrence Professor Mark Sutton Professor Danny O'Hare Professor Alison Holmes Dr Timothy Miles Rawson |
| author_facet | Miss Jennifer Lawrence Professor Mark Sutton Professor Danny O'Hare Professor Alison Holmes Dr Timothy Miles Rawson |
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| description | Introduction: The emergence of Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae poses a significant therapeutic challenge. Current antimicrobial susceptibility testing methods have limitations in detecting and characterising ESBL pathogens. With broad-spectrum beta-lactam use creating selective pressure, our goal is to develop an in vitro method for detecting and quantifying ESBL production, correlating with minimum inhibitory concentrations, to enhance precision of antimicrobial therapy selection and improve clinical outcomes. Methods: Gold electrodes were coated with iridium oxide to create a pH sensitive sensor. Beta-lactam antibiotics undergo hydrolysis by beta-lactamase, causing a pH decrease at the sensor surface, detected as an increase in open circuit potential.After successful fabrication, sensors were tested using E. coli ATCC 25922 (susceptible negative) and E. coli ATCC 35218 (BL-producing). Bacteria was cultured, diluted to 0.5 McFarland standard (1.5 × 108 CFU/mL) and added to MH broth (1:10 dilution). Sensors in the bacterial solution were allowed to stabilise before introducing 5mL of amoxicillin (512mg/L). After 2 minutes, open circuit potentials were recorded, and data analysed by plotting potential changes over time. Triplet repeats were carried out.A clinical validation study was conducted at Charing Cross Hospital (London, December 2023), involving 26 E. coli patient samples. Following the above method, each sample, previously plated, was adjusted to a 0.5 McFarland standard and added to MH broth. Sensors were added to the sample and allowed to stabilise before adding 5mL amoxicillin (512mg/L). The absolute change in potential was recorded after 2 minutes but samples were allowed to continue to run for 10 minutes, providing a comprehensive assessment of the biosensor response to clinically relevant samples in a healthcare setting. Results: The potential change for each sample was recorded and categorised as non-ESBL or ESBL based on predetermined thresholds. Results were compared to the routine susceptibility testing findings of the microbiology laboratory. A box plot was created, demonstrating distinct differences between the susceptible and ESBL-producing E. coli samples, with average absolute changes of 7.11mV and 16.84mV, respectively. Discussion: Following comparison with laboratory findings, the biosensors showed 89.47% sensitivity and 100% specificity (17 true positives, 7 true negatives, 2 false negatives), with an overall accuracy of 92.3%. The two false negatives exhibited lower absolute changes in potential during treatment, suggesting they may have been producing beta-lactamase enzyme at low levels. Conclusion: The findings indicate that an iridium oxide-based biosensor can effectively detect a change in ESBL concentration under standard in vitro conditions. This approach holds promise as a low-cost and innovative ESBL detection and quantification tool, particularly suitable for low- or middle-income countries (LMICs). Future research will extend to broader clinical applications and assess the impact of additional beta-lactamases like ampC and carbapenemases, aiming ultimately at comprehensive beta-lactamase quantification. |
| format | Article |
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| spelling | doaj-art-b5ec3ddd168a42e5808029b4059f84352025-08-20T02:17:08ZengElsevierInternational Journal of Infectious Diseases1201-97122025-03-0115210764410.1016/j.ijid.2024.107644Iridium oxide-based biosensors: A novel method for ESBL detection and quantificationMiss Jennifer Lawrence0Professor Mark Sutton1Professor Danny O'Hare2Professor Alison Holmes3Dr Timothy Miles Rawson4The NIHR Health Protection Research Unit In Healthcare Associated Infections and Antimicrobial Resistance, Imperial College LondonUK Health Security AgencyDepartment of Bioengineering, Imperial College LondonThe NIHR Health Protection Research Unit In Healthcare Associated Infections and Antimicrobial Resistance, Imperial College LondonThe NIHR Health Protection Research Unit In Healthcare Associated Infections and Antimicrobial Resistance, Imperial College LondonIntroduction: The emergence of Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae poses a significant therapeutic challenge. Current antimicrobial susceptibility testing methods have limitations in detecting and characterising ESBL pathogens. With broad-spectrum beta-lactam use creating selective pressure, our goal is to develop an in vitro method for detecting and quantifying ESBL production, correlating with minimum inhibitory concentrations, to enhance precision of antimicrobial therapy selection and improve clinical outcomes. Methods: Gold electrodes were coated with iridium oxide to create a pH sensitive sensor. Beta-lactam antibiotics undergo hydrolysis by beta-lactamase, causing a pH decrease at the sensor surface, detected as an increase in open circuit potential.After successful fabrication, sensors were tested using E. coli ATCC 25922 (susceptible negative) and E. coli ATCC 35218 (BL-producing). Bacteria was cultured, diluted to 0.5 McFarland standard (1.5 × 108 CFU/mL) and added to MH broth (1:10 dilution). Sensors in the bacterial solution were allowed to stabilise before introducing 5mL of amoxicillin (512mg/L). After 2 minutes, open circuit potentials were recorded, and data analysed by plotting potential changes over time. Triplet repeats were carried out.A clinical validation study was conducted at Charing Cross Hospital (London, December 2023), involving 26 E. coli patient samples. Following the above method, each sample, previously plated, was adjusted to a 0.5 McFarland standard and added to MH broth. Sensors were added to the sample and allowed to stabilise before adding 5mL amoxicillin (512mg/L). The absolute change in potential was recorded after 2 minutes but samples were allowed to continue to run for 10 minutes, providing a comprehensive assessment of the biosensor response to clinically relevant samples in a healthcare setting. Results: The potential change for each sample was recorded and categorised as non-ESBL or ESBL based on predetermined thresholds. Results were compared to the routine susceptibility testing findings of the microbiology laboratory. A box plot was created, demonstrating distinct differences between the susceptible and ESBL-producing E. coli samples, with average absolute changes of 7.11mV and 16.84mV, respectively. Discussion: Following comparison with laboratory findings, the biosensors showed 89.47% sensitivity and 100% specificity (17 true positives, 7 true negatives, 2 false negatives), with an overall accuracy of 92.3%. The two false negatives exhibited lower absolute changes in potential during treatment, suggesting they may have been producing beta-lactamase enzyme at low levels. Conclusion: The findings indicate that an iridium oxide-based biosensor can effectively detect a change in ESBL concentration under standard in vitro conditions. This approach holds promise as a low-cost and innovative ESBL detection and quantification tool, particularly suitable for low- or middle-income countries (LMICs). Future research will extend to broader clinical applications and assess the impact of additional beta-lactamases like ampC and carbapenemases, aiming ultimately at comprehensive beta-lactamase quantification.http://www.sciencedirect.com/science/article/pii/S1201971224007197 |
| spellingShingle | Miss Jennifer Lawrence Professor Mark Sutton Professor Danny O'Hare Professor Alison Holmes Dr Timothy Miles Rawson Iridium oxide-based biosensors: A novel method for ESBL detection and quantification International Journal of Infectious Diseases |
| title | Iridium oxide-based biosensors: A novel method for ESBL detection and quantification |
| title_full | Iridium oxide-based biosensors: A novel method for ESBL detection and quantification |
| title_fullStr | Iridium oxide-based biosensors: A novel method for ESBL detection and quantification |
| title_full_unstemmed | Iridium oxide-based biosensors: A novel method for ESBL detection and quantification |
| title_short | Iridium oxide-based biosensors: A novel method for ESBL detection and quantification |
| title_sort | iridium oxide based biosensors a novel method for esbl detection and quantification |
| url | http://www.sciencedirect.com/science/article/pii/S1201971224007197 |
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