Study: Crosstalk Inside Cells Helps Pathogens Evade Drugs

By Erin Frick

ALBANY, N.Y. (Jan. 28, 2026) — Biologists have uncovered a new mode of communication inside cells that helps bacterial pathogens learn how to evade drugs. Their findings, published in the journal Nature Communications, describe how these mechanisms drive antimicrobial resistance in Listeria monocytogenes, the foodborne bacteria that causes listeriosis. 

The work is a collaboration between researchers at the University at Albany and the New York State Department of Health and could inform the development of new drugs and, potentially, future approaches for personalized medicine.

“Antibiotic resistance is on the rise globally,” said UAlbany’s Cheryl Andam, associate professor in the Department of Biological Sciences and scientific director of the Life Sciences Research. “Patients are acquiring infections that we used to be able to treat, but as bacterial strains are becoming increasingly virulent and resistant to multiple types of drugs, providers are running out of options. In the race to understand how this is happening, our latest findings unlock a critical piece of the puzzle: bacteria contain intricate communication networks and the players within them are able to talk and collaborate in ways that were previously unknown.”

Andam likened the discovery to realizing that distinct populations of people thought not to share a language are in fact communicating and learning from each other. 

“Inside cells, there are what we call ‘mobile genetic elements’ — short fragments of DNA that carry information and come in many different forms, all with different functions and structures,” Andam said. “We group these elements into categories (e.g. plasmids, phages and transposons) based on their traits. 

“Before this study, we knew that mobile genetic elements of a particular type could exchange information with each other — both within a given cell and between cells. What we didn’t know is that different types of mobile genetic elements can also talk to each other by swapping pieces of DNA, passing along information that helps the pathogen build resistance to drugs and boost transmissibility. This understanding greatly expands our view of intercellular communication and also how pathogens evolve to become more deadly.”

Mapping Information Pathways Inside Cells 

While many foodborne pathogens only affect the digestive system, listeriosis can spread into normally sterile parts of the body including blood and the brain, giving rise to life threatening conditions such as sepsis, meningitis and encephalitis. The invasive form of listeriosis is a major public health threat, with a mortality rate of 20-30%.

In this study, the researchers examined how mobile genetic elements transfer DNA sequences, including antimicrobial resistance genes, in L. monocytogenes by analyzing bacterial genome sequences and mapping genetic connections between different types of mobile genetic elements.

The analysis included DNA sequences extracted from 936 L. monocytogenes samples taken from patients with listeriosis in New York State between 2000 and 2021. 

Using specialized computer programs, the researchers identified different types of mobile genetic elements in the bacterial genomes. Their analysis included 2,332 mobile genetic elements total, focusing on three main types: plasmids, phages and transposons.

To understand how these mobile genetic elements share DNA with each other, the researchers created a network diagram where each mobile genetic element was represented as a dot and connections between mobile genetic elements that shared similar DNA sequences were shown as lines. By identifying DNA sequences of a minimum length and matching them among mobile genetic elements, they were able to trace information exchange across the different mobile genetic element types. 

This finding fundamentally changes our understanding of how clinically relevant bacterial traits, including antimicrobial resistance, spread.

“DNA transfer among different types of mobile genetic elements dramatically broadens the distribution and mobility of antimicrobial resistance genes and virulence genes,” Andam said. “When these different types of elements exchange genetic material, they can create new combinations of resistance genes — for example, a mobile genetic element carrying three resistance genes can acquire three more from another element, resulting in a carrier with six resistance genes. Bacterial cells that acquire such elements can learn to resist multiple types of antibiotics, making infections increasingly difficult to treat.”

“The sequencing we perform in our laboratory contributes to national and local surveillance of foodborne pathogens,” said senior coauthor on the study Kimberlee Musser, Chief of Bacterial Disease at the New York State Department of Health's Wadsworth Center. “In addition to surveillance, we are excited to contribute this pathogen sequencing data to answer research questions like those explored in this study in order to enhance our overall understanding of foodborne disease.” 

The study also carries important implications for combatting major clinical challenges like increased virulence and multi-drug resistance.

“Understanding how bacteria become resistant to drugs that were once able to kill them is a critical question in biomedical research,” Andam said. “Someday, we hope our work could inform the development of new, more powerful drugs. It could also be put to use as a predictive strategy. As we learn more about the nuanced mechanisms at play inside different strains of a particular pathogen, it becomes possible to better predict which medication will be most effective at treating a given strain. This could help a provider identify the best treatment more efficiently, improving outcomes for the patient when time is of the essence.”