The water used to prepare intravenous solutions in a hospital contained endotoxins. Infection control personnel performed plate counts to find the source of the bacteria. Their results:
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All of the following conclusions about the bacteria can be drawn except which one?
a. They were present as a biofilm in the pipes.
b. They are gram-negative.
c. They come from fecal contamination.
d. They come from the city water supply.
e. none of the above