Using a Surrogate Model System to Screen for Pathogen(s) Associated with SCTLD

This work focused on the use of an insect larvae model to help replace some of the coral samples needed to screen for pathogenic microorganisms involved with SCTLD. Results showed there is a strong correlation between larval mortality and mucus samples from SCTLD lesions, suggesting that G. mellonella is a suitable surrogate system for pathogenic bacteria associated with SCTLD. Results from the antibiotic trials indicate that it is more likely that pathogenic Gram-negative bacteria are associated with SCLTD lesions. There also seems to be a correlation between previous treatment of corals with amoxicillin and increased resistance to the antibiotic as various Vibrio spp. belonging to the Harveyi Clade have been isolated from SCTLD lesions and have high resistance to amoxicillin. Though the 30 pathogenic bacteria isolated from this project might not be the primary pathogen, they could be lethal opportunistic or coinfections. More research needs to be done to rule out Gram-positive bacteria as causative agents, and more investigation is needed to determine the connection between the isolates and the amoxicillin treatment conferring resistance.