A new curious congruence involving multiple harmonic sums

Let PnPn denote the set of positive integers which are prime to n  . Let BnBn be the n  -th Bernoulli number. For any prime p>5p>5 and integer r≥2r≥2, we prove that∑l1+l2+⋯+l5=prl1,⋯,l5∈Pp1l1l2l3l4l5≡−5!6pr−1Bp−5(modpr). This gives an extension of a family of curious congruences found by the author, Cai and Zhao.