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Bacteria are everywhere. They are all around you, inside of you and are you. For every bacterium there are at least ten phages, or bacteria-specific viruses, that can infect them. 

When phages infect and reproduce inside bacteria, the consequences can be dire. Phages that infect bacteria can contribute to their drug-resistance and ability to cause disease. A new study led by University of Maine researchers aims to find out why. 

A deeper understanding of phages’ ability to influence bacteria could allow for more targeted medical treatment of often drug-resistant diseases. Despite these viruses being the most abundant biological entity on earth, many people do not know what they are, and fewer are studying them. 

Research led by Sally Molloy, 91���� associate professor of genomics, is seeking to change that. Thanks to a recently awarded National Institutes of Health (NIH) R15 grant, Molloy’s  research team will continue to investigate phages’ abilities to promote drug resistance in bacteria. It will also help her expand the hands-on experiences she offers to get undergraduate students involved in potentially life-saving science. 

According to World Health Organization’s , “In 2023, approximately one in six laboratory-confirmed bacterial infections worldwide were caused by bacteria resistant to antibiotics.”

Phages specifically target bacteria. They have two abilities. The first is acting as a parasite within bacteria. They infect the bacteria, reproduce and when their progeny are released, kill the bacteria cells. The second ability phages have is more interesting. 

“They live latently, quietly, maybe borderline symbiotically with the bacterium by integrating their viral genome into the bacterial genome,” said Molloy. 

When the phage integrates its genome into the host bacteria, the cell does not die. Instead, it enhances the bacterial cell’s survival skills, by providing resistance to infection by other phages and sometimes by providing resistance to antibiotics.

Molloy’s research looks at the genes phages bring into bacteria. Specifically, she’s studying how they contribute to increased drug resistance. The bacteria Molloy and her team study are part of a group of Gram positive bacteria that include important pathogens, including Mycobacterium tuberculosis, which kills more people worldwide than any other infectious agent, and M.  abscessus, one of the most drug-resistant pathogens.

These diseases can be closer to home than some may think. M. abscessus-chelonae is a non-tuberculosis mycobacteria that causes pulmonary and soft-tissue infections and can be multi-drug or totally drug resistant. It causes pulmonary and soft-tissue infections in the elderly, immunocompromised and in patients with chronic lung diseases such as cystic fibrosis. 

Scientists have found some success treating the drug resistant disease with phage therapy, which uses injected phages to target and kill bacteria causing disease. Molloy’s research into how phages influence drug-resistance in bacteria may provide opportunities for other researchers to improve treatment of mycobacterial disease using both drug and phage treatments. 

Molloy first came to 91���� as a graduate student and has remained through her Ph.D. and postdoctoral research. Within the Department of Molecular and Biomedical Sciences and the Honors College, Molloy integrates teaching with her research to engage undergraduate and graduate students in active learning. With a recently awarded NIH R15 grant, Molloy is training undergraduates as part of her research into phages.

For the students in Molloy’s lab, partaking in this research can be especially important. 

“If you’re doing research that’s going to make a difference with this real world problem, how you learn and what you learn completely changes,” said Molloy. “You’re applying your knowledge to a real problem that you care about and maybe the whole community cares about.” 

This work has the potential to save lives, not just through treating disease, but by training the next generation of doctors, scientists and researchers in the field of microbiology. 

“We’re training them for the work force and to be ready to be contributors for whatever problems they’re going to be working on,” said Molloy. 

With the support of the NIH R15 grant, Molloy will be able to continue to bring more undergraduate students like Vejune Griciute and Edib Redzematovic into her lab, where they continue to work on understanding phages and their contribution to bacteria drug resistance. 

“It’s more motivating to learn things when you feel like you’re making important contributions to something that really matters, not only to you but to a community,” she said.

The importance of phages cannot be underestimated. 

“They impact our lives every single day,” said Molloy. “We’re exposed to them everywhere.” With Molloy and her team of students, research is paving the way towards using the innate ability of phages as a treatment rather than a disease.

By Emma Beauregard, research media intern

Contact: Erin Miller, erin.miller@maine.edu