Interchange derivative and summation?

Question

I would like to know, if we have: $$I=\frac{d^2}{dx^2}\sum_{k=0}^{\infty}\binom{x}{k}\frac{1}{a+k}, ~~x, a>0$$

then interchange order of derivative and summation, $$I=\sum_{k=0}^{\infty}\frac{d^2}{dx^2} \binom{x}{k}\frac{1}{a+k}$$ is valid?