# Rapid, efficient determination of bacteriophage susceptibility

> **NIH NIH R21** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2021 · $195,625

## Abstract

Cystic Fibrosis (CF) patients commonly are challenged by bacterial infections, including with non-
tuberculosis Mycobacteria (NTM) such as Mycobacterium abscessus and Mycobacterium avium.
These can present substantial clinical challenges because of their resistance to antibiotics and
poor responsiveness to antibiotic therapy. Lung transplantation can substantially improve the
severe pulmonary difficulties of CF, but immunosuppressive drugs supporting transplantation
facilitate dissemination of NTM infection and high mortality rates. We recently reported the
successful use of a bacteriophage cocktail to treat a 15-year old CF patient in London who had a
bilateral lung transplant and suffered from a life-threatening M. abscessus infection. This study
strongly suggests that if an effective cocktail of phages can be formulated for a specific patient
infection, that a therapeutic intervention with phages can be very effective. However, the
approach is not generally applicable to all NTM infections or even all M. abscessus infections,
due to high strain variation in phage susceptibility profiles. That is, phages that are effective for
one patient are not effective for other patients. The primary goal of this proposal is to develop a
simple, quick, timely, and moderate-throughput assay for screening clinical isolates of NTB
strains – as well as M. tuberculosis strains – for phage susceptibility. This assay also has the
potential to monitor the emergence of phage resistance during the course of therapy. The assay
is based on the simple concept of constructing a suite of candidate phages carrying a fluorescent
reporter gene, such that fluorescence is emitted when the phages successfully infect a particular
strain. Phage susceptibility can then be monitored in a microtiter plate format within a few hours,
with simple discrimination between strains that are suspectable and those that are not. The
challenge to constructing a suite of such phages has been addressed by developing a modified
engineering strategy that simplifies the construction and broadens the types of phages that can
be engineered. The reporter phage suite will be evaluated on a set of clinical isolates to
determine their profiles of expression, sensitivity, and the feasibility of multiplexing phages with
different `colored' reporters. Once validated, this reporter assay should facilitate the testing of
large numbers of clinical NTM isolates to determine those for which phage intervention is a viable
option. The ability to simply and quickly monitor the emergence of resistance during TB treatment
will advance the prospects of TB clinical trials.

## Key facts

- **NIH application ID:** 10114210
- **Project number:** 5R21AI151264-02
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Graham F. Hatfull
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $195,625
- **Award type:** 5
- **Project period:** 2020-03-01 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10114210

## Citation

> US National Institutes of Health, RePORTER application 10114210, Rapid, efficient determination of bacteriophage susceptibility (5R21AI151264-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10114210. Licensed CC0.

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