In March 2016, we sampled tap water from 5 homes and 6 small businesses in Flint, with ALL testing culture-negative for Legionella. We used a standard culture-method often used by hospitals to determine if there is a risk of Legionnaire’s Disease outbreak. This is good news. We will be following up with another sampling this summer when the weather is warmer and there is more of a tendency of Legionella bacteria to grow.
We are also examining the water samples we have collected more closely using DNA-based methods. The DNA methods may help us detect lower levels of Legionella that we couldn’t see with culture and also identify different kinds of Legionella, but the trade-off is that we will not be able to tell the difference between live and dead bacteria. That is why the culture method is considered the standard for determining risk of getting Legionnaires’ Disease from tap water.
Using the best available science, the sampling we performed in March 2016 showed that if any living Legionella were present, their levels were low the day of testing. There is always some risk of Legionnaire’s Disease from tap water, but our current results from March suggest the risk was not concerning at any of our sample sites in Flint. We will remain vigilant in our tracking and testing of this potential problem in Flint homes.