  We study quantum corrections to holographic mutual information for two
disjoint spheres at a large separation by using the operator product expansion
of the twist field. In the large separation limit, the holographic mutual
information is vanishing at the semiclassical order, but receive quantum
corrections from the fluctuations. We show that the leading contributions from
the quantum fluctuations take universal forms as suggested from the boundary
CFT. We find the universal behavior for the scalar, the vector, the tensor and
the fermionic fields by treating these fields as free fields propagating in the
fixed background and by using the 1/n prescription. In particular, for the
fields with gauge symmetries, including the massless vector boson and massless
graviton, we find that the gauge parts in the propagators play indispensable
role in reading the leading order corrections to the bulk mutual information.
