Dihydrostreptomycin is an antibiotic belonging to the aminoglycoside class, used to combat bacterial infections. While its direct use in human medicine has largely ceased, its history illustrates the evolving landscape of antibiotic therapy.
What is Dihydrostreptomycin
Dihydrostreptomycin is a semi-synthetic antibiotic, meaning it is derived from a natural source and then chemically modified. It originates from Streptomyces griseus, a type of soil bacterium known for producing various antibiotics. As an aminoglycoside, it shares structural similarities with other drugs in its class, characterized by amino sugars linked by glycosidic bonds. This chemical structure gives it a broad spectrum of activity against many different types of bacteria.
How Dihydrostreptomycin Works
Dihydrostreptomycin exerts its antibacterial effect by interfering with the process of protein synthesis within bacterial cells. It specifically targets the bacterial ribosome, a cellular machinery responsible for building proteins. The antibiotic binds irreversibly to the S12 protein within the 30S ribosomal subunit. This binding disrupts the formation of the initiation complex, which is the first step in translating genetic information into proteins. Consequently, the bacteria produce defective and non-functional proteins, ultimately leading to the death of the bacterial cell.
Past and Present Applications
Historically, dihydrostreptomycin played a significant role in treating various bacterial infections in humans, including tuberculosis. Currently, it finds primary application in veterinary medicine, where it is used to treat bacterial infections in animals. For instance, it has been used for intramammary infections in dry cows to reduce existing infections and prevent new ones caused by Staphylococcus aureus. It has also been applied in treating leptospirosis in animals such as dogs, horses, and swine.
Reasons for Decreased Use
The decline in human use of dihydrostreptomycin stems from its severe side effects. Ototoxicity, leading to irreversible hearing loss, was a substantial risk, outweighing its benefits as safer alternatives became available. Another serious side effect is nephrotoxicity, or kidney damage.
The development of bacterial resistance also contributed to its decreased effectiveness over time. As bacteria evolved, some developed mechanisms to counteract the antibiotic’s action, rendering it less potent against infections it once effectively treated. Furthermore, the pharmaceutical landscape has advanced, with the development of newer, safer, and more effective antibiotics. These modern alternatives offer a better safety profile and broader efficacy, making dihydrostreptomycin a less favorable option for human treatment. The FDA formally withdrew its approval for human drug products containing dihydrostreptomycin sulfate, solidifying its restricted status.