Significance

Bacterial cytological profiling (BCP) is a well-established method to determine the mechanism of action (MOA) for antibiotics by examining the morphological changes that occur when bacteria are treated with a compound of interest. This study demonstrates the application of convolutional neural networks (CNN) to overcome technical challenges with a traditional approach to BCP, creating a robust platform to rapidly determine MOA for Mycobacterium tuberculosis. We demonstrate the capability of this platform by using it to confirm the MOA of several compounds that target M. tuberculosis. Our findings underscore the potential of CNN-based BCP to enhance the accuracy and efficiency of MOA determination, particularly for challenging pathogens like M. tuberculosis.

Abstract

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a significant global health threat, affecting an estimated 10.6 million people in 2022. The emergence of multidrug resistant and extensively drug resistant strains necessitates the development of novel and effective drugs. Accelerating the determination of mechanisms of action (MOAs) for these drugs is crucial for advancing TB treatment. This study introduces MycoBCP, a unique adaptation of bacterial cytological profiling (BCP) tailored to M. tuberculosis, utilizing the application of convolutional neural networks (CNNs) within BCP to overcome challenges posed by traditional image analysis techniques. Using MycoBCP, we analyzed the morphological effects of various antimicrobial compounds on M. tuberculosis, capturing broad patterns rather than relying on precise cell segmentation. This approach circumvented issues such as cell clumping and uneven staining, which are prevalent in M. tuberculosis. In a blind test, MycoBCP accurately identified the MOA for 96% of the compounds, with a single misclassification of rifabutin, which was incorrectly categorized as affecting translation rather than transcription. The similar morphologies resulting from transcription and translation inhibition indicate a need for further refinement to distinguish them more effectively. Application of MycoBCP to a series of antitubercular agents successfully identified known MOAs and revealed unique effects, demonstrating its utility in early drug discovery and development. Our findings underscore the potential of CNN-based BCP to enhance the accuracy and efficiency of MOA determination, particularly for challenging pathogens like M. tuberculosis. MycoBCP represents a significant advancement in TB drug development, offering a robust and adaptable method for high-throughput screening of antimicrobial compounds.

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Data, Materials, and Software Availability

Code and example files (27) can be found at github.com/MycoBCP/MycoBCP. Some study data are available. Training data for the CNN described in this manuscript exceeds 40,000 high resolution fluorescence microscopy images. Instead, we provide a checkpoint of the trained network that can be used on similar images.

Acknowledgments

Research was supported by the Bill and Melinda Gates Foundation (INV-040479 Joseph Sugie) for the purpose of supporting M. tuberculosis drug development.

Author contributions

D.Q., T.P., J.P., and J.S. designed research; D.Q., M.S., S.A., L.A., A.B., A.D., and J.S. performed research; J.S. contributed new reagents/analytic tools; D.Q., M.S., J.P., and J.S. analyzed data; and J.P. and J.S. wrote the paper.

Competing interests

D.Q., M.S., and J.S. are employed by Linnaeus Bioscience, Inc. J.P. has an equity interest in Linnaeus Bioscience Incorporated and receive consulting income from the company. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies.

Supporting Information

Appendix 01 (PDF)

References

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Information & Authors

Information

Published in

The cover image for PNAS Vol.122; No.6
Proceedings of the National Academy of Sciences
Vol. 122 | No. 6
February 11, 2025
PubMed: 39913203

Classifications

Data, Materials, and Software Availability

Code and example files (27) can be found at github.com/MycoBCP/MycoBCP. Some study data are available. Training data for the CNN described in this manuscript exceeds 40,000 high resolution fluorescence microscopy images. Instead, we provide a checkpoint of the trained network that can be used on similar images.

Submission history

Received: October 22, 2024
Accepted: January 8, 2025
Published online: February 6, 2025
Published in issue: February 11, 2025

Change history

March 17, 2025: The text of this article has been updated; please see accompanying Correction for details. Previous version (February 6, 2025)

Keywords

  1. microbiology
  2. drug discovery
  3. Mycobacterium tuberculosis
  4. antimicrobials
  5. convolutional neural networks

Acknowledgments

Research was supported by the Bill and Melinda Gates Foundation (INV-040479 Joseph Sugie) for the purpose of supporting M. tuberculosis drug development.
Author contributions
D.Q., T.P., J.P., and J.S. designed research; D.Q., M.S., S.A., L.A., A.B., A.D., and J.S. performed research; J.S. contributed new reagents/analytic tools; D.Q., M.S., J.P., and J.S. analyzed data; and J.P. and J.S. wrote the paper.
Competing interests
D.Q., M.S., and J.S. are employed by Linnaeus Bioscience, Inc. J.P. has an equity interest in Linnaeus Bioscience Incorporated and receive consulting income from the company. The terms of this arrangement have been reviewed and approved by the University of California, San Diego in accordance with its conflict-of-interest policies.

Notes

This article is a PNAS Direct Submission.

Authors

Affiliations

Diana Quach
Linnaeus Bioscience, Inc., San Diego, CA 92109
Linnaeus Bioscience, Inc., San Diego, CA 92109
Sara Ahmed
Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109
Lauren Ames
Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109
Amala Bhagwat
Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109
Aditi Deshpande
Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109
Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA 98109
Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98109
Joe Pogliano
Department of Molecular Biology, University of California, San Diego, CA 92093
Linnaeus Bioscience, Inc., San Diego, CA 92109

Notes

1
To whom correspondence may be addressed. Email: [email protected].

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Deep learning–driven bacterial cytological profiling to determine antimicrobial mechanisms in Mycobacterium tuberculosis
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