  In a recent paper (Phys. Rev. B {\bf 78}, 075316 (2008)), Sajeev and Moiseyev
demonstrated that the bound-to-resonant transitions and lifetimes of
autoionizing states in spherical quantum dots can be controlled by varying the
confinment strength. In the present paper, we report that such control can in
some cases be compromised by the presence of Coulomb impurities. It is
demonstrated that a screened Coulomb impurity placed in the vicinity of the dot
center can lead to bound-to-resonant transitions and to avoided crossings-like
behavior when the screening of the impurity charge is varied. It is argued that
these properties also can have impact on electron transport through quantum dot
arrays.
