Targeting anaerobic respiration in Pseudomonas aeruginosa with chlorate improves healing of chronic wounds

• Published in: Advances in wound care (New Rochelle, N.Y.)
• Main Authors: Kim, Jane Hannah, Spero, Melanie, Lebig, Elyson Gavin D, Lonergan, Zachery R, Trindade, Inês B, Newman, Dianne K, Martins-Green, Manuela
• Format: Journal Article
• Language: English
• Published: United States 01.02.2024
• ISSN: 2162-1918; 2162-1934
• DOI: 10.1089/wound.2023.0036

Pseudomonas aeruginosa is an opportunistic pathogen that can establish chronic infections and form biofilm in wounds. Because the wound environment is largely devoid of oxygen, P. aeruginosa may rely on anaerobic metabolism, such as nitrate respiration, to survive in wounds. While nitrate reductase (Nar) typically reduces nitrate to nitrite, it can also reduce chlorate to chlorite which is a toxic oxidizing agent. Therefore, chlorate can act as a pro-drug to specifically eradicate hypoxic/anoxic, nitrate-respiring P. aeruginosa populations, which are often tolerant to conventional antibiotic treatments. Using a diabetic mouse model for chronic wounds, we tested the role that anaerobic nitrate respiration plays in supporting chronic P. aeruginosa infections. P. aeruginosa forms biofilm deep within the wound where the environment is anoxic. Daily treatment of P. aeruginosa-infected wounds with chlorate supported wound healing. Chlorate treatment was as effective as treatment with ciprofloxacin (a conventional antibiotic that targets both oxic and hypoxic/anoxic P. aeruginosa populations). Chlorate-treated wounds showed markers of good-quality wound healing, including well-formed granulation tissue, reepitheliazation and microvessel development. Loss- and gain-of-function experiments showed that P. aeruginosa requires nitrate respiration to establish a chronic wound infection and form biofilms. We show that the small molecule chlorate, kills the opportunistic pathogen, Pseudomonas aeruginosa, by targeting a form of anaerobic metabolism called nitrate respiration. Chlorate holds promise as a treatment to combat diverse bacterial infections where oxygen is limiting and/or where pathogens grow as biofilms because many other pathogens have nitrate reductases and survive using anaerobic metabolism.