Bacterial and protozoal deoxyribonucleic acid (DNA) (DNA)

Bacterial and protozoal deoxyribonucleic acid (DNA) is the primary molecular target for nitroimidazole antibiotics, such as metronidazole, in anaerobic and microaerophilic organisms (StatPearls, 2023). These pathogens possess unique metabolic pathways that utilize low-redox-potential electron transport proteins, including ferredoxin and pyruvate:ferredoxin oxidoreductase, to reduce the nitro group of the drug (PubChem, 2024). This reductive process generates highly reactive, short-lived nitro radical intermediates that interact directly with the microbial DNA. The resulting damage includes the formation of covalent adducts, loss of the helical structure, and extensive strand breakage, which collectively inhibit DNA synthesis and lead to rapid cell death (NIH, 2022). Because the reductive activation of these drugs occurs only under low-oxygen conditions, the DNA of aerobic host cells remains unaffected, providing a high degree of selective toxicity against anaerobic bacteria and certain protozoal pathogens. This mechanism is fundamental to the treatment of infections caused by Bacteroides, Clostridium, and Trichomonas species.

Other names

Microbial DNABacterial DNAProtozoal DNAGenomic DNADeoxyribonucleic acid

Reductive activation of the nitro group by microbial enzymes creates reactive radical intermediates that cause DNA strand breakage and inhibit nucleic acid synthesis (StatPearls, 2023; PubChem, 2024).