Drew Bridges
Assistant Professor
- Pittsburgh PA
Bridges's lab uncovers signals bacteria use to coordinate their behaviors, aiming to turn those signals into new ways to treat infections.
Biography
In the long term, the research program will expand to other microorganisms and their unique lifestyles to learn what principles are general and which are species-specific. These discoveries will be relevant to infection and could inform the development of approaches to manipulate bacterial behavior, potentially leading to new strategies for controlling disease.
Areas of Expertise
Media Appearances
CMU Study Uncovers How Dangerous Bacteria Build and Break Down Biofilms
Mellon College of Science News online
2026-06-29
“Our platform can be used to inform researchers of the genes that underlie the biofilm regulation of diverse species and could be used to identify new biofilm-disrupting drugs,” Bridges said. “Simultaneously, this paper really lays out the fundamental genetics underlying the specific pathogen S. pneumoniae.”
Researchers Identify New Target To Fight Antibiotic Resistance
Mellon College of Science News online
2025-12-18
Drew Bridges, an assistant professor in Carnegie Mellon University’s Mellon College of Science, said the research could be an important tool in fighting a growing threat.
“Traditional antibiotics work in a simple way — they kill bacteria,” Bridges said. “It's the same problem as with chemotherapy — the survivors cause problems. When you apply a bunch of antibiotics, a subpopulation of cells survives, they repopulate the population, and they're all resistant.”
We’re Outta Here | Novel imaging technique tracks individual bacterial cells as they leave their biofilm community
Mellon College of Science News online
2025-04-29
“Being able to transition in and out of the biofilms is critical for bacteria to be able to spread between niches. It could be between some environmental locations or, more relevantly, it could be between hosts or infection sites,” said Drew Bridges, assistant professor in the Department of Biological Sciences.
Biologists determine bacteria sense damage to relatives
Phys.org online
2024-03-26
"If you saw an injured person, you'd probably try to protect yourself or you'd be on edge, and that's what we see with the bacteria," Bridges said. "They have the ability to sense internal components of their kin, and if they sense it, they respond by preparing themselves for an encounter with a threat."
Media
Education
Princeton University:
Postdoctoral Fellowship
2022
Dartmouth College
Ph.D.
Biological Sciences
2016
Appalachian State University
B.S.
Chemistry
2011
Links
Articles
A branching cell-fate decision in biofilm dispersal enables long-term surface persistence
bioRxivKasivisweswaran, S., Prentice, J.A., Bridges, A.A.
2026
Biofilms are the most ancient multicellular communities on Earth, representing a primitive developmental system that protects microbes from threats. Biofilm dispersal, whereby bacteria exit biofilms, is critical for the spread of pathogens to new infection sites. Here, using Vibrio cholerae, we show that dispersal events are accompanied by a branching cell-fate decision. While ~90% of cells disperse, a viable subpopulation remains within a residual matrix. This post-dispersal biofilm community (PDBC) is established by the matrix protein RbmA and adopts a specialized anabolic program that enhances tolerance to antibiotics and bacteriophages. Our findings reveal that PDBCs act as a resilient "seed-bank" capable of rapidly re-populating the niche without requiring de novo matrix biosynthesis, providing a mechanistic basis for the recurrence and spread of chronic infections.
Label-free microscopy enables high-throughput identification of genes controlling biofilm development
mBioMR, P., Prentice, J.A., Eutsey, R.A., Mikheyeva, I., Hiller, N.L., Bridges, A.A.
2026
The biofilm mode of growth plays a critical role in microbial ecology and in the persistence of human pathogens. Yet, much remains unknown regarding the molecular determinants of biofilms in human pathogens. In this study, we present label-free analysis of biofilms (LFAB), an imaging approach that combines time-lapse, low-magnification brightfield microscopy with regional optical density measurements to quantify biofilm biomass. Unlike other approaches to biofilm biomass quantification, LFAB enables real-time, non-perturbative, and high-throughput monitoring of biofilms. We validated LFAB in diverse microbes and found that our measurements strongly correlate with traditional biofilm assays. We then used LFAB to identify and characterize critical factors mediating biofilm formation in Streptococcus pneumoniae, a major human pathogen whose biofilm lifecycle is known to be intimately related to colonization and infection.
A small periplasmic protein governs broad physiological adaptations in Vibrio cholerae via regulation of the DbfRS two-component system
Nature CommunicationsNguyen, E., Agbavor, C., Steenhaut, A., Pratyush M. R., Hiller, N. L., Cahoon, L. A., Mikheyeva, I. V., Ng, W.L., Bridges, A. A.
2025
Two-component signaling pathways allow bacteria to sense and respond to environmental changes, yet the sensory mechanisms of many remain poorly understood. In the pathogen Vibrio cholerae, the DbfRS two-component system controls the biofilm lifecycle, a critical process for environmental persistence and host colonization. Here, we identified DbfQ, a small periplasmic protein encoded adjacent to dbfRS, as a direct modulator of pathway activity. DbfQ directly binds the sensory domain of the histidine kinase DbfS, shifting it toward phosphatase activity and promoting biofilm dispersal. In contrast, outer membrane perturbations, caused by mutations in lipopolysaccharide biosynthesis genes or membrane-damaging antimicrobials, activate phosphorylation of the response regulator DbfR.
An Exciting Future for Microbial Molecular Biology and Physiology.
mBioBridges, A. A, Guthrie, L., Lehman, M., Kellogg, E., Miranda, S., Pountain, A., Shriver, A., Varble, A., Kaplan, H., Shank, E., Storz, G.
2025
Continuous advances in technologies ranging from deep sequencing and genetic manipulation to mass spectrometry, single cell imaging, and structural biology have led to previously unimaginable advances in our understanding of microbial physiology and the molecular mechanisms underlying microbial responses in a multitude of environments. Simultaneously, these advances are revealing how much more there is to learn. At the 2024 virtual retreat of the Molecular Biology and Physiology (MBP) Community of the Council on Microbial Sciences (COMS) of the American Society for Microbiology (ASM), eight early-career investigators, along with retreat attendees, discussed some of these astounding advances, as well as the challenges and opportunities the developments raise. Motivated by these discussions, we review the state-of-the-art in molecular microbiology and provide an outlook on this field. Our hope is that the topics discussed here can serve as an inspiration for the development of future technologies, resources, and guidelines and for the training of the next generation of microbiologists.
Biofilm dispersal patterns revealed using far-red fluorogenic probes
PLoS BiologyPrentice, J.A., Kasivisweswaran, S., van de Weerd, R., Bridges, A. A.
2024
Bacteria frequently colonize niches by forming multicellular communities called biofilms. To explore new territories, cells exit biofilms through an active process called dispersal. Biofilm dispersal is essential for bacteria to spread between infection sites, yet how the process is executed at the single-cell level remains mysterious due to the limitations of traditional fluorescent proteins, which lose functionality in large, oxygen-deprived biofilms. To overcome this challenge, we developed a cell-labeling strategy utilizing fluorogen-activating proteins (FAPs) and cognate far-red dyes, which remain functional throughout biofilm development, enabling long-term imaging. Using this approach, we characterize dispersal at unprecedented resolution for the global pathogen Vibrio cholerae. We reveal that dispersal initiates at the biofilm periphery and approximately 25% of cells never disperse. We define novel micro-scale patterns that occur during dispersal, including biofilm compression during cell departure and regional heterogeneity in cell motions. These patterns are attenuated in mutants that reduce overall dispersal or that increase dispersal at the cost of homogenizing local mechanical properties.
Pneumococcal Extracellular Vesicles Mediate Horizontal Gene Transfer via the Transformation Machinery
mSphereLass, S. W., Camphire, S., Smith, B. E., Eutsey, R. A., Prentice, J. A., Yerneni, S. S., Arun, A., Bridges, A. A., Rosch, J.W., Conway, J. F., Campbell, P., Hiller, N. L.
2024
Bacterial cells secrete extracellular vesicles (EVs), the function of which is a matter of intense investigation. Here, we show that the EVs secreted by the human pathogen Streptococcus pneumoniae (pneumococcus) are associated with bacterial DNA on their surface and can deliver this DNA to the transformation machinery of competent cells. These findings suggest that EVs contribute to gene transfer in Gram-positive bacteria and, in doing so, may promote the spread of drug resistance genes in the population.
mSphere of Influence: The complex world of bacterial biogeography
mSphereBridges, A. A.
2023
Drew Bridges works in the field of bacterial signal transduction and studies the formation and disassembly of bacterial biofilms. In this mSphere of Influence article, he reflects on how the paper “Biogeography of a human oral microbiome at the micron scale” by Mark Welch et al. (J. L. Mark Welch, B. J. Rossetti, C. W. Rieken, F. E. Dewhirst, et al., Proc Natl Acad Sci U S A 113:E791–E800, 2016, https://doi.org/10.1073/pnas.1522149113) inspired him to change his research trajectory.
Cell-lysis sensing drives biofilm formation in Vibrio cholerae
Nature CommunicationsPrentice, J.A., van de Weerd, R., Bridges, A. A.
2018
Matrix-encapsulated communities of bacteria, called biofilms, are ubiquitous in the environment and are notoriously difficult to eliminate in clinical and industrial settings. Biofilm formation likely evolved as a mechanism to protect resident cells from environmental challenges, yet how bacteria undergo threat assessment to inform biofilm development remains unclear. Here we find that population-level cell lysis events induce the formation of biofilms by surviving Vibrio cholerae cells. Survivors detect threats by sensing a cellular component released through cell lysis, which we identify as norspermidine. Lysis sensing occurs via the MbaA receptor with genus-level specificity, and responsive biofilm cells are shielded from phage infection and attacks from other bacteria. Thus, our work uncovers a connection between bacterial lysis and biofilm formation that may be broadly conserved among microorganisms.