SBIR/STTR Award attributes
PROJECT SUMMARYAminoglycosides are one of the cheapest and well-known antibiotics in clinical use for over 70 years, but one of the major limitations in their use is their ototoxicity. We are developing fast and low-cost methods to develop aminoglycosides with anti-ribosomal activities and reduced toxicity. In this project, we will identify novel aminoglycoside antibacterials, that show reduced ototoxicity. Complexes between ribosomal components will be exploited as targets for small molecule drug libraries that- inactivate the ribosome, stopping bacterial protein synthesis and causing bacterial death while reducing toxicity. This work addresses an important health issue, antibiotic ototoxicity, and presents creative steps towards a novel solution to this problem.Cases of multidrug-resistant (MDR, resistance to 2-3 classes), extensive drug resistance (XDR, resistance to most classes except colistin or tigecycline) and even pan drug resistance (PDR, resistance to all classes) nosocomial bacterial infections have skyrocketed in recent years, and the emergence of pan drug- resistant isolates are making these infections increasingly difficult to treat. Hospital-acquired infections like these account for up to 4% of all hospital stays in the United States and are incredibly diverse in causative pathogen, antibiotic resistance profile, and severity. A significant cause of nosocomial infection is the Enterobacteriaceae family, which includes Gram-negative bacilli that can be commensal or pathogenic. Enterobacteriaceae have a widespread clinical and economic impact due to the diversity of infections they cause; this family causes many infections such as pneumonia, bloodstream infections (BSIs), urinary tract infections (UTIs), and intra-abdominal infections (IAIs). The World Health Organization (WHO) lists carbapenem-resistant Enterobacteriaceae (CRE) as having a critical need for novel antibiotics on their Priority Pathogens list. Because the mortality of these multi drug-resistant infections is between 30 and 50% and there is such difficulty in finding viable treatments, the need for novel therapeutics for these pathogens must be addressed.Unless innovative strategies are developed to produce robust and effective new classes of antibiotics, health care costs will continue to climb and we will completely lose our ability to combat even the most common infection. Influenza and coronavirus (SARS and COVID-19) create an even more urgent need for targeting resistant bacteria related to lung infections, such as carbapenem-resistant Enterobacteriaceae (CRE), a common example of CRE being Klebsiella Pneumoniae (KP). A recent article by J. Gerberding, former CDC director states, “The patients at greatest risk from superbugs like CRE, CR-A. buamanii and CR-P. aeruginosa and other bacterial pathogens that can cause lung diseases, are the ones who are already more vulnerable to illness from viral lung infections like influenza, severe acute respiratory syndrome (SARS), and COVID-19. The 2009 H1N1 influenza pandemic, for example, claimed nearly 300,000 lives around the world. Many of those deaths — between 29% and 55% — were actually caused by secondary bacterial pneumonia, according to the CDC.” A recent study (Zhou, Lancet 2020, 395, 1054-1062) from Wuhan reports that almost 50% of COVID-19 related deaths showed evidence of secondary bacterial infections (pneumonia, sepsis, bloodstream infections). Clearly, more work needs to be done to better understand the role of secondary bacterial infections in COVID-19 related morbidities, and develop non-toxic interventions in parallel.One of the challenges of research in infectious diseases is to find ways to use the increasing knowledge of the mechanisms underlying disease biology, transformation and progression to develop novel therapeutic strategies for MDR, XDR, and PDR bacterial infections. Targeting heavily conserved RNA structures, present in the 4 billion years old bacterial ribosome, and involved in proliferation and survival of bacteria, is a promising approach. RNA, the essential nucleic acid component of the ribosome, is a validated target for drug design, both as therapeutic and as a target. The work proposed here, a multidisciplinary effort using rapid methods of synthesis, bacterial inhibition and zebrafish screening assays in Phase I studies, will be further developed in Phase II using in vivo efficacy and ototoxicity studies using guinea pig models. The success of the proposed work would be a significant addition to currently available approaches in antibacterial therapy. We propose using novel aminoglycoside modifications, patented NUBAD assays, and preliminary results from a zebrafish screening assay and mouse organ culture to identify conjugates that show reduced ototoxicities, opening possibilities for developing aminoglycosides that can target resistant pathogens with much improved therapeutic indices.PROJECT NARRATIVE The proposed project presents a strategy for developing novel aminoglycoside therapeutics with reduced ototoxicities with evasion of resistance. Antimicrobial resistance occurs when microorganisms (often infectious bacteria, viruses, and certain parasites) are no longer sensitive to drugs that were previously used to treat them; this is of global concern because it hampers our ability to control infectious disease and increases the costs of health care. In order to combat this world-wide problem, innovative strategies for antibiotic drug design must be implemented. The proposed research describes a strategy for improving the therapeutic index of aminoglycosides by designing novel structures that lower their ototoxicity and evade common resistance pathways.
