Hybrid Antibiotics for Persistent Infections

The goal of this project is to develop a new class of urea-depsipeptide (UDEP) antibiotics to treat prosthetic joint infections (PJI). UDEPs kill bacteria through activation of the ClpP protease, causing cells to self-digest. This unique activating mechanism allows UDEPs to kill biofilms and non-growing persister cells, which are prevalent in PJI and explain why current antibiotics are largely ineffective. Current therapies involve weeks to months of antibiotic treatment, debridement surgeries, and medical device replacement. UDEPs have the potential to minimize surgical interventions due to PJI and improve patient care. PJI are primarily caused by the Gram-positive pathogens Staphylococcus aureus and epidermidis and the UDEPs are potently active against these pathogens, including multi-drug resistant strains. A recent advance in our UDEP medical chemistry program yielded a new compound which has improved safety, solubility, and bone penetration compared to first generation UDEPs. A preliminary study found that the compound was effective in a K-wire femur medullary canal implant model of PJI, which is known to be difficult to treat. In this project, we will evaluate if the compound is an acceptable pre-clinical candidate for PJI by testing it in a series of in vitro and in vivo studies focused on this indication. Specifically, the aims are to 1) scale up the compound; 2) determine the microbiological and biofilm killing effect against the main pathogens isolated from PJI; and 3) determine the efficacy of the compound in mouse and rabbit models of PJI. mRNA profiles of Staphylococcus aureus subsp. aureus ATCC 33591 strains (wild-type, ARI-4206 resistant, and Rifampin resistant strains) after exposure to 1/2 minimal inhibitory concentration of ARI-5192 (0.5 mg/L), ARI-4206 (0.125 mg/L), Rifampin (0.004 mg/L) or DMSO for 30 minutes.