Not a drug, exactly, but a treatment with a bacteria specific virus called a phage.
From Wikipedia
Bacteriophages or "phage" are viruses that invade bacterial cells and, in the case of lytic phages, disrupt bacterial metabolism and cause the bacterium to lyse [destruct]. Phage Therapy is the therapeutic use of lytic bacteriophages to treat pathogenic bacterial infections. Phage therapy is an alternative to antibiotics, being developed for clinical use by many western research groups in Europe and the US. It has been extensively used and developed in the former Soviet Union.
The treatment is effective by using a phage virus to infect and kill specific bacteria whilst not interacting with the surrounding human tissue or other harmless bacteria. The virus replicates quickly so a single, small dose is usually sufficient.
Phages are currently being used therapeutically to treat bacterial infections that do not respond to conventional antibiotics.
The Russians at one time led the world in classical genetics so it's not surprising that they would have pioneered work with phages. Not all bacteria are attacked by phages. Some are resistant. Some mutate to become resistant. The battle is ongoing. The Soviets however, were never pioneers of new drugs. Not then. Not now.