title: Ceftriaxone Pulse Dosing Fails to Eradicate Biofilm-Like MicrocolonyB. burgdorferiPersisters Which Are Sterilized by Daptomycin/ Doxycycline/Cefuroxime without Pulse Dosing.
abstract: Although the majority of Lyme disease patients can be cured, at least 10-20% of the patients continue to suffer from persisting symptoms such as fatigue, muscular and joint pain, and neurologic impairment after standard 2-4 week antibiotic treatment. While the causes for this post-treatment Lyme disease symptoms are unclear, one possibility is due toBorrelia burgdorferipersisters that are not effectively killed by current antibiotics such as doxycycline or amoxicillin used to treat Lyme disease. A previous study showed that four rounds of ceftriaxone pulse dosing treatment eradicatedB. burgdorferipersistersin vitrousing a relatively young late log phase culture (5 day old). In this study, we investigated if ceftriaxone pulse dosing could also eradicateB. burgdorferipersisters in older stationary phase cultures (10 day old) enriched with more resistant microcolony form of persisters. We found that ceftriaxone pulse dosing could only eradicate planktonic log phaseB. burgdorferispirochetal forms and round body forms but not more resistant aggregated biofilm-like microcolony persisters enriched in stationary phase cultures. Moreover, we found that not all drugs are suitable for pulse dosing, with bactericidal drugs ceftriaxone and cefuroxime being more appropriate for pulse dosing than bacteriostatic drug doxycycline and persister drug daptomycin. We also showed that drug combination pulse dosing treatment was more effective than single drug pulse dosing. Importantly, we demonstrate that pulse dosing treatment impaired the activity of the persister drug daptomycin and its drug combination againstB. burgdorferipersisters and that the most effective way to kill the more resistant biofilm-like microcolonies is the daptomycin/doxycycline/ceftriaxone triple drug combination without pulse dosing. Our findings indicate pulse dosing may not always work as a general principle but rather depends on the specific drugs used, with cidal drugs being more appropriate for pulse dosing than static or persister drugs, and that drug combination approach with persister drugs is more effective at killing the more resistant microcolony form of persisters than pulse dosing. These observations may have implications for more effective treatment of Lyme disease. Future studies are required to validate these findings in animal models ofB. burgdorferipersistence.
authors.affiliation: Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University Baltimore, MD, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University Baltimore, MD, USA.
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University Baltimore, MD, USA.
authors.forename: Wanliang
authors.initials: W
authors.lastname: Shi
authors.affiliation: Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University Baltimore, MD, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
keywords: Borrelia burgdorferi; biofilm; drug combination; persisters; pulse dosing