Peptide-Conjugated Phosphorodiamidate Morpholino Oligomers Retain Activity against Multidrug-Resistant Pseudomonas aeruginosa and .

Most antimicrobials currently in the clinical pipeline are modifications of existing classes of antibiotics and are considered short-term solutions due to the emergence of resistance. represents a major challenge for new antimicrobial drug discovery due to its versatile lifestyle, ability to develop resistance to most antibiotic classes, and capacity to form robust biofilms on surfaces and in certain hosts such as those living with cystic fibrosis (CF). A precision antibiotic approach to treating could be achieved with an antisense method, specifically by using peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs). Here, we demonstrate that PPMOs targeting (acyl carrier protein), (UDP-(3--acyl)--acetylglucosamine deacetylase), and (30S ribosomal protein S10) inhibited the growth of several multidrug-resistant clinical isolates at levels equivalent to those that were effective against sensitive strains. Lead PPMOs reduced established pseudomonal biofilms alone or in combination with tobramycin or piperacillin-tazobactam. Lead PPMO dosing alone or combined with tobramycin in an acute pneumonia model reduced lung bacterial burden in treated mice at 24 h and reduced morbidity up to 5 days postinfection. PPMOs reduced bacterial burden of extensively drug-resistant in the same model and resulted in superior survival compared to conventional antibiotics. These data suggest that lead PPMOs alone or in combination with clinically relevant antibiotics represent a promising therapeutic approach for combating infections. Numerous Gram-negative bacteria are becoming increasingly resistant to multiple, if not all, classes of existing antibiotics. Multidrug-resistant bacteria are a major cause of health care-associated infections in a variety of clinical settings, endangering patients who are immunocompromised or those who suffer from chronic infections, such as people with cystic fibrosis (CF). Herein, we utilize antisense molecules that target mRNA of genes essential to bacterial growth, preventing the formation of the target proteins, including , , and We demonstrate here that antisense molecules targeted to essential genes, alone or in combination with clinically relevant antibiotics, were effective in reducing biofilms and protected mice in a lethal model of acute pneumonia.