Scientists wanted to know how certain mouth bacteria (from the Enterobacteriaceae family) are able to survive and live in the sterile hospital environment and end up infecting patients. To figure out how these bacteria continued to live, they took hundreds of mouth bacteria samples and placed them in separate, food-free test tubes. Each day, they tested to see how many of the bacteria survived. Since the mouth normally provides a daily food source, this experiment tested to see how long these bacteria could live without food. As expected, most of the mouth bacteria died within a few days. Three species did well in the starvation experiment: Klebsiella pneumonia, Klebsiella oxytoca and klebsiella alcalifaciens. Normally, these bacteria only accounted for .1% of the total bacteria in the mouth, which is pretty low. In this experiment though, they lasted for 100 days.
In looking at these long lasting mouth bacteria’s genetics, they found that they had undergone a genetic mutation, which allowed them to survive without food. The other mouth bacteria did not undergo any genetic mutations, so they could not adapt to the starvation environment.
This puts new light on how these bacteria can survive and infect patients in hospitals, even when many steps have been taken to make them very sterile and safe. Just a few bacteria, laying basically dormant for up to 100 days, can still find its way into hospital settings and cause infection. This research may also inform how hospitals disinfect operating rooms and change their safety protocols to keep patients safe and infection free.