An innovative metabolic engineering strategy for the discovery of novel macrolide antibiotics

DESCRIPTION provided by applicant The rapid emergence of multi drug resistant pathogenic microorganisms represents a major threat to public health placing an ever increasing demand for the discovery of new antibacterial agents Macrolide antibiotics such as the membered macrolide erythromycin and second generation analogs clarithromycin and azithromycin are among the first line therapies clinically employed to treat respiratory tract infections However as a consequence of the clinical overuse of these agents macrolide resistance mechanisms have rapidly emerged In contrast membered macrolides have demonstrated the capability of overcoming resistance mechanisms that affect and membered macrolides Indeed a few select membered macrolides have been successfully employed in the clinical treatment of bacterial infections outside of the United States Despite their demonstrated potential however membered macrolides still remain underexplored in the development of new human antibacterial agents The tylosin biosynthetic pathway produces a series of membered macrolides of which the veterinary therapeutic tylosin is best known In this SBIR proposal Alluvium Biosciences proposes to genetically engineer the tylosin biosynthetic pathway to enable the production of novel membered macrolide compounds for application in new antibiotic drug discovery In this effort a genetically engineered Streptomyces fradiae strain will be generated via genomic integration of the heterologous cytochrome P monooxygenase mycG This cytochrome P is native to the mycinamicin biosynthetic pathway that is responsible for the production of the mycinamicin family of membered macrolides in Micromonospora griseorubida It has previously been established that during the biosynthesis of the mycinamicins MycG activity installs a regio and stereospecific hydroxyl and or epoxide functionality onto the mycinamicin core scaffold resulting in both mono and di oxidized bioactive compounds It is established that this oxidative functionality is critical for mycinamicin bioactivity Based on preliminary work Alluvium expects that the engineered S fradiae strain will be capable of producing hybrid tylosin based analogs featuring an oxidation pattern similar to that observed in the mycinamicin family of macrolides As it is known that the regio and stereospecific oxidative functionalities can influence the bioactivity of macrolide compounds Alluvium hypothesizes that the novel membered macrolides will display potency against macrolide resistant bacterial pathogens Accordingly in vitro evaluation of antibacterial activities against a series of bacterial strains including those that display macrolide resistance will be performed within this initial Phase I study If the hypothesis is supported compounds demonstrating promising activity will proceed to Phase II Randamp D wherein Alluvium will pursue medicinal chemistry efforts in order to optimize pharmacological properties and establish a lead macrolide antibiotic candidate PUBLIC HEALTH RELEVANCE Macrolides antibiotics are among the first line of defense for the treatment of infectious diseases in both human and animals The rapid emergence and spread of multi drug resistant bacteria represents one of the major threats to public health placing an ever increasing demand for novel antibiotics including macrolides This SBIR Phase I research proposes to develop an innovative technology for the discovery of novel macrolide antibiotics to overcome bacterial resistance in the treatment of infectious disease