Nitroxoline as a promising alternative drug for the treatment of Lyme disease based on an in-vitro study

Lyme disease (LD) is the most common vector-borne disease in USA and Europe and is caused by Borrelia burgdorferi. Despite proper treatment, approximately one fifth of patients will develop post-treatment LD syndrome (PTLDS), a condition which is poorly understood. One of the possible causes is thought to be due to persister forms of B. burgdorferi that are not effectively killed by the current Lyme antibiotics. In this study, we evaluated nitroxoline, an antibiotic used to treat urinary tract infections, for its activity against a stationary-phase culture enriched with persister forms of B. burgdorferi. Nitroxoline was found to be equivalent in activity against B. burgdorferi to cefuroxime (standard Lyme antibiotic) in different experiments. Moreover, we found that the three-drug combination cefuroxime + nitroxoline + clarithromycin eradicated 98.3% of stationary phase bacteria in the drug-exposure experiment and prevented the regrowth in the subculture study after drug exposure, as well as two-drug combinations cefuroxime + nitroxoline and clarithromycin + nitroxoline. These drug combinations should be further evaluated in a LD mouse model to assess if eradication of persister forms of B. burgdorferi in-vivo is possible and if so, whether nitroxoline could be repurposed as an alternative drug for the treatment of LD.