A new study from the biotech firm BioMed Valley Discoveries has shown that injecting hard to treat tumors with a specific strain of bacteria resulted in decreased tumor sizes and, in some cases, a complete elimination of the tumor mass.

The idea of using bacteria as a means to fight cancer is not new.  Doctors have noticed for over a century that certain cancer patients who contract massive bacterial infections show a decrease in tumor mass.  Treatment by injecting bacteria into the body though did not work consistently or efficiently enough to be used in clinical practice.

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Now, lead author Dr. Saurabh Saha and his team have been able to tailor Clostridium novyi, a Gram-positive anaerobic bacteria, to eliminate tumors from the inside.  Most tumors have a tightly packed anaerobic core, meaning there is no oxygen present.  While this results in death (and thus the black color) of some of the tumor tissue, other cells still live. The compact nature of the tumor prevents chemotherapeutic drugs from reaching the still-dividing interior cells, resulting in inefficient treatment.

Dr. Saha and his team had previously shown positive results of tumor shrinkage and disappearance in mice and dogs by injecting C. novyi spores directly into the tumor mass.  The anaerobic nature of the tumor provides a perfect growing environment for the bacteria.  As the bacteria grow, they release short-range toxins against the tissue, killing the cancer cells.  Also, the immune system recognizes an infection, and begins increasing inflammation and immune cell invasion in the area, further resulting in decreased tumor mass.  Because C. novyi is unable to survive in oxygenated conditions, the bacteria die as soon as the colonies grow outside the interior tumor environment.

In the past, bacterial injections led to infection and sepsis, since the bacteria were not anaerobic and the molecular techniques to edit a bacteria’s genome were unavailable.  Dr. Saha and his team were able to remove the long acting toxins within C. novyi, preventing them from seeping into the test subjects.  This technique allowed them medical approval to inject a 53-year-old woman’s right shoulder tumor with 10,000 C. novyi spores.  An initial abscess formed as the immune system responded to the injection, but periodic MRI imaging in the following month showed a drastic decrease in tumor size with no undue side effects, including bacterial poisoning.

This approach could be used in the future to treat the hard-to-reach interior of a tumor.  With targeted nanoparticle approaches that will specifically attack the outside of a designated tumor, the combined therapies could completely eliminate very specific cancer nodules without any extreme side effects.  Says Nicholas Roberts, a co-author of the paper and a postdoctoral fellow at the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, “There is a lot of hope in moving forward with this [therapy].” For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page