# ESBL-triggered exponential amplification for culture-free phenotypic detection of MDR pathogens

> **NIH NIH R21** · UNIV OF MARYLAND, COLLEGE PARK · 2020 · $229,265

## Abstract

PROJECT SUMMARY/ABSTRACT
Infections driven by extended-spectrum β-lactamase (ESBL)-producing bacteria are resistant to most or all
penicillins and cephalosporins. However, there is significant risk in defaulting to carbapenems to treat any
infection potentially resulting from broad- or extended-spectrum β-lactamase-producers. The use of
carbapenems (a drug of last resort) may contribute to even more dangerous antimicrobial resistance and thus
it is imperative to immediately and specifically confirm ESBL-based resistance in order to ensure that the
selected therapeutic simultaneously minimizes risk to the patient and to the public. Current methods rely on
culture of the pathogenic organisms, which requires more than 24 hours for identification. Our team aims to
create a rapid (1 hr) and culture-free tool to phenotypically screen for ESBL-producing pathogens. We propose
to synthesize a molecular trigger in which a cephalosporin is covalently attached to a single-stranded DNA
oligonucleotide near the 3’ end. Without ESBL enzyme activity, the oligo cannot be extended by DNA
polymerase; upon ESBL activity, the cephalosporin is released, enabling the DNA to be extended along DNA
templates present in the assay, implying that DNA amplification can be triggered specifically by ESBL activity.
Hence, we are proposing to combine the phenotypic detection of ESBL activity with the detection power of
DNA amplification. The proposed approach results in an immediate discrimination of ESBL-driven resistance,
thus enabling rapid treatment without sacrificing antibiotic stewardship.

## Key facts

- **NIH application ID:** 9958281
- **Project number:** 1R21AI151929-01
- **Recipient organization:** UNIV OF MARYLAND, COLLEGE PARK
- **Principal Investigator:** Ian M White
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $229,265
- **Award type:** 1
- **Project period:** 2020-08-20 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9958281

## Citation

> US National Institutes of Health, RePORTER application 9958281, ESBL-triggered exponential amplification for culture-free phenotypic detection of MDR pathogens (1R21AI151929-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9958281. Licensed CC0.

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