For two un-related quantities, the Heisenberg uncertainty equations holds: the prduct of the two uncertainty quantities is greater than [tex]\hbar/2[/tex]
Example of unrelated quantities are position and momentum, energy and time.
Thus
[tex]\Delta x*\Delta p \ \textgreater \ \hbar/2[/tex]
Knowing the speed of the bacteria the uncertainty in its position is
[tex]\Delta x \ \textgreater \ \hbar/(2 \Delta p) =\hbar/(2mv)[/tex]