White plague disease has significantly affected Caribbean corals over the last two decades. This disease syndrome is characterized by rapid tissue loss leaving behind dead, white coral skeleton. While three types of white plague have been recognized based on how quickly the disease progresses, the pathogens that trigger this disease have not been identified with certainty. Following the Summer 2014 hyperthermal event along the Florida Reef Tract (FRT), we monitored an outbreak of white plage II (WPII) from the early onset of the disease affecting the Pillar coral Dendrogyra cylindrus. In order to identify potential disease-causing agents, changes of the microbial communities were tracked during five-month progression of the outbreak in in this coral species on a reef site in the FRT using 454 high-throughput sequencing of the 16S rRNA gene. Multivariate analyses comparing the microbial communities of the same coral colonies before and after showing signs of disease, compared with coral colonies that remained healthy throughout the entire outbreak, showed both an influence of sampling time and a clear effect of disease condition. Strong correlations were found between the appearance of white plague disease and highly abundant bacterial species from the genus Sphingobium, Sphingomonas and Pseudoalteromonas. Follow up studies using isolates cultured from active white plague colonies in trial infections will allow confirming the actual pathogen or group of pathogens causing the disease from among these identified bacterial candidates