Your gut has millions of bacteria in it, but not all bacteria make you sick. The millions of bacteria in your gut are called a microbiota and they help keep you healthy. Just like a fingerprint everyone’s gut microbiota is unique with trillions of bacteria in your gut and over 1,000 different species.The factors that make your gut microbiota different are your age, diet, environment, genetics and medication. The differences in one’s gut microbiota might have a greater significance than originally thought.
Scientists believe that the differences in the gut microbiota are the reason certain cancer patients don’t respond to the new cancer treatments. The new cancer treatment that scientist studied, in relation to the gut microbiota, is immunotherapy, particularly checkpoint inhibition. Immunotherapy aims to rapidly shrink or disappear advanced tumors. While doing this study, Scientists found that certain bacteria, “good” bacteria in the gut, are linked to a patient responding well to the treatment and “bad” bacteria is linked to the unresponsiveness of the immunotherapy.
So what makes a bacteria good or bad ? In this study, the “good” bacteria helps immune cells recognize tumor cells. The “bad“ bacteria interfere with the immune cells functions.
One of the studies to find the “good” and “bad’ bacteria were done on melanoma patients. Scientist had a sample size of 42 patients and took a stool sample prior to giving them the immunotherapy treatment. They found ten types of bacteria in common between the people but each person had a different ratio of those bacterias. Out of those ten they found that eight of the different types of bacteria were more abundantly in people that responded to the treatment (classified as “good” bacteria) and two types of bacteria were more abundant in the people that didn’t respond to the treatment (“bad” bacteria).
In another study done, cancer patients that took an antibiotic after having done the immunotherapy don’t live as long as the cancer patients that didn’t take the antibiotics. As shown bacteria can also be good and even help fight illnesses in our bodies. But the antibiotics that are being overprescribed are causing issues in our bodies because antibiotics kill harmful bacteria but they also kill the good bacteria.