Competition between macroalgae and corals for occupying the available space in sea bed is an important ecological process underlying coral-reef dynamics. We investigate coral- macroalgal phase shift in presence of macroalgal allelopathy and microbial infection on corals by means of an eco-epidemiological model under the assumption that the transmission of infection occurs through both contagious and non-contagious pathways. We found that the system is capable of exhibiting the existence of two stable configurations by saddle-node bifurcations.