Evaluation of Natural and Botanical Medicines for Activity Against Growing and Non-growing Forms of B. burgdorferi

Essential Oils and their Active Constituents Effective against Non-growing Mycobacterium intracellulare

BACKGROUND

Mycobacterium intracellulare (M. intracellulare) is a common, slow-growing opportunistic pathogen that can cause chronic pulmonary and extrapulmonary infections. Despite its rising incidence, standard treatments are often ineffective in eradicating M. intracellulare, leading to prolonged treatment and high recurrence rates, likely due to persistence of non-growing bacteria. Although essential oils are known for their antimicrobial properties, their effects on M. intracellulare, particularly in its non-growing phase, have not been well studied.

METHODS

We screened 151 essential oils to assess their antimicrobial activity against stationary-phase non-growing M. intracellulare. Essential oils with significant activity were further evaluated at different concentrations by MIC and drug exposure tests.

RESULTS

Thirty-four essential oils were found to have activity at 5000 µg/mL, with 18 showing effectiveness at 1250 µg/mL. Six essential oils, Ajwain, Oregano, Palmarosa, Thyme, Mountain Savory, and Litsea Cubeba had the highest activity, achieving 100% bacterial clearance after one day exposure. Carvacrol, the key active component of Ajwain, Oregano, Thyme, Mountain Savory, eradicated stationary-phase bacteria at 310 µg/mL concentration within one day, while citronellol, the active component of Palmarosa, at 630 µg/mL achieved complete clearance after three day exposure.

CONCLUSIONS

We have newly identified several essential oils, including Ajwain, Oregano, Thyme, Mountain Savory, Palmarosa, and Litsea Cubeba and their active components such as carvacrol and citronellol, to have promising activity against M. intracellulare, and these findings may have implications for developing improved treatments for M. intracellulare infections.

Antiviral Activity of Water-Alcoholic Extract of Cistus incanus L

Recently, previously known viruses have changed their pathogenicity and encompassed new types of host populations. An example of such an infection is that caused by SARS-CoV, belonging to the "well-known" coronavirus family. Another group of viruses that are of great importance to the human population are the herpes viruses. Due to increasing viral resistance to existing antiviral drugs, plant extracts are attracting increasing interest due to their complex composition and their simultaneous attack of different viral targets. Based on the above, we tested the antiviral potential of water-alcoholic extract obtained from a commercial sample of the plant Cistus incanus L. against the enveloped viruses SvHA1, SvHA2 (ACV resistant) and HCoV 229E. The results showed both complete inhibition of the intracellular stages of the viral replication and a strong effect on extracellular virions in the three viral models. In a study of the effect on the replication of SvHA 2, the calculated selectivity index was over 10. From the experiments on the virucidal effects on the two herpes viruses, it was found that the viral titer of the samples decreased by about 4 lg compared to the control sample. The extract is of interest for introduction into practice.

Borrelia burgdorferi tolerates alteration to P66 porin function in a murine infectivity model

Borrelia burgdorferi exists in a complex enzootic life cycle requiring differential gene regulation. P66, a porin and adhesin, is upregulated and essential during mammalian infection, but is not produced or required within the tick vector. We sought to determine whether the porin function of P66 is essential for infection. Vancomycin treatment of B. burgdorferi cultures was used to screen for P66 porin function and found to generate spontaneous mutations in p66 (bb0603). Three novel, spontaneous, missense P66 mutants (G175V, T176M, and G584R) were re-created by site-directed mutagenesis in an infectious strain background and tested for infectivity in mice by ID50 experiments. Two of the three mutants retained infectivity comparable to the isogenic control, suggesting that B. burgdorferi can tolerate alteration to P66 porin function during infection. The third mutant exhibited highly attenuated infectivity and produced low levels of P66 protein. Interestingly, four isolates that were recovered for p66 sequencing from mouse tissues revealed novel secondary point mutations in genomic p66. However, these secondary mutations did not rescue P66 porin function. New structural modeling of P66 is presented and consistent with these experimental results. This is the first work to assess the contribution of P66 porin function to B. burgdorferi pathogenesis.

Bacterial persisters: molecular mechanisms and therapeutic development

Persisters refer to genetically drug susceptible quiescent (non-growing or slow growing) bacteria that survive in stress environments such as antibiotic exposure, acidic and starvation conditions. These cells can regrow after stress removal and remain susceptible to the same stress. Persisters are underlying the problems of treating chronic and persistent infections and relapse infections after treatment, drug resistance development, and biofilm infections, and pose significant challenges for effective treatments. Understanding the characteristics and the exact mechanisms of persister formation, especially the key molecules that affect the formation and survival of the persisters is critical to more effective treatment of chronic and persistent infections. Currently, genes related to persister formation and survival are being discovered and confirmed, but the mechanisms by which bacteria form persisters are very complex, and there are still many unanswered questions. This article comprehensively summarizes the historical background of bacterial persisters, details their complex characteristics and their relationship with antibiotic tolerant and resistant bacteria, systematically elucidates the interplay between various bacterial biological processes and the formation of persister cells, as well as consolidates the diverse anti-persister compounds and treatments. We hope to provide theoretical background for in-depth research on mechanisms of persisters and suggest new ideas for choosing strategies for more effective treatment of persistent infections.

Case report: Substantial improvement of autism spectrum disorder in a child with learning disabilities in conjunction with treatment for poly-microbial vector borne infections

Poly-microbial vector-borne infections may have contributed to neuropsychiatric symptoms in a boy diagnosed with autism spectrum disorder. Targeted antimicrobial treatment resulted in substantial improvement in cognitive (such as learning disabilities, focus, concentration) and neurobehavioral (such as oppositional, defiant, anti-social, disordered mood, immaturity, tics) symptoms.

Artemisinin as a therapeutic vs. its more complex Artemisia source material

Covering: up to 2017-2022Many small molecule drugs are first discovered in nature, commonly the result of long ethnopharmacological use by people, and then characterized and purified from their biological sources. Traditional medicines are often more sustainable, but issues related to source consistency and efficacy present challenges. Modern medicine has focused solely on purified molecules, but evidence is mounting to support some of the more traditional uses of medicinal biologics. When is a more traditional delivery of a therapeutic appropriate and warranted? What studies are required to establish validity of a traditional medicine approach? Artemisia annua and A. afra are two related but unique medicinal plant species with long histories of ethnopharmacological use. A. annua produces the sesquiterpene lactone antimalarial drug, artemisinin, while A. afra produces at most, trace amounts of the compound. Both species also have an increasing repertoire of modern scientific and pharmacological data that make them ideal candidates for a case study. Here accumulated recent data on A. annua and A. afra are reviewed as a basis for establishing a decision tree for querying their therapeutic use, as well as that of other medicinal plant species.

The Use of Natural Bioactive Nutraceuticals in the Management of Tick-Borne Illnesses

The primary objective of this paper is to provide an evidence-based update of the literature on the use of bioactive phytochemicals, nutraceuticals, and micronutrients (dietary supplements that provide health benefits beyond their nutritional value) in the management of persistent cases of Borrelia burgdorferi infection (Lyme disease) and two other tick-borne pathogens, Babesia and Bartonella species. Recent studies have advanced our understanding of the pathophysiology and mechanisms of persistent infections. These advances have increasingly enabled clinicians and patients to utilize a wider set of options to manage these frequently disabling conditions. This broader toolkit holds the promise of simultaneously improving treatment outcomes and helping to decrease our reliance on the long-term use of pharmaceutical antimicrobials and antibiotics in the treatment of tick-borne pathogens such as Borrelia burgdorferi, Babesia, and Bartonella.

Dipsacus and Scabiosa Species-The Source of Specialized Metabolites with High Biological Relevance: A Review

The genera Dipsacus L. and Scabiosa L. of the Caprifoliaceae family are widely distributed in Europe, Asia, and Africa. This work reviews the available literature on the phytochemical profiles, ethnomedicinal uses, and biological activities of the most popular species. These plants are rich sources of many valuable specialized metabolites with beneficial medicinal properties, such as triterpenoid derivatives, iridoids, phenolic acids, and flavonoids. They are also sources of essential oils. The genus Dipsacus has been used for centuries in Chinese and Korean folk medicines to treat bone (osteoporosis) and joint problems (rheumatic arthritis). The Korean Herbal Pharmacopoeia and Chinese Pharmacopoeia include Dipsaci radix, the dried roots of D. asperoides C.Y.Cheng & T.M.Ai. In addition, S. comosa Fisch. ex Roem & Schult. and S. tschiliiensis Grunning are used in traditional Mongolian medicine to treat liver diseases. The current scientific literature data indicate that these plants and their constituents have various biological properties, including inter alia antiarthritic, anti-neurodegenerative, anti-inflammatory, antioxidant, anticancer, and antimicrobial activities; they have also been found to strengthen tendon and bone tissue and protect the liver, heart, and kidney. The essential oils possess antibacterial, antifungal, and insecticidal properties. This paper reviews the key biological values of Dipsacus and Scabiosa species, as identified by in vitro and in vivo studies, and presents their potential pharmacological applications.

A Comprehensive Review of Herbal Supplements Used for Persistent Symptoms Attributed to Lyme Disease

Context

Lyme disease is the most common, tick-borne disease in the USA. While most patients successfully recover with antibiotics, some patients experience persistent symptoms for months to years. Patients who attribute chronic symptoms to Lyme disease commonly use herbal supplements. The complexity, variability in dose and formulation, and lack of data for these herbal compounds make it difficult to assess their efficacy and safety.

Objective

This review examines the evidence for the antimicrobial activity, safety, and drug-drug interactions of 18 herbal supplements that patients commonly use for treatment of persistent symptoms attributed to Lyme disease.

Design

The research team performed a narrative review by searching the PubMed, Embase, Scopus, Natural Medicines databases, and NCCIH website. The search used the keywords for 18 herbal compounds: (1) andrographis (Andrographis paniculate), (2) astragalus (Astragalus propinquus), (3) berberine, (4) cat's claw bark (Uncaria tomentosa), (5) cordyceps (Cordyceps sinensis), (6) cryptolepis (Cryptolepis sanguinolenta), (7) Chinese skullcap (Scutellaria baicalensis), (8) garlic (Allium sativum), (9) Japanese knotwood (Polygonum cuspidatum), (10) reishi mushrooms (Ganoderma lucidum), (11) sarsaparilla (Smilax medica), (12) Siberian ginseng (Eleutherococcus senticosus), (13) sweet wormwood (Artemisia annua), (14) teasle root (Dipsacus fullonum), (15) lemon balm (Melissa officinalis), (16) oil of oregano (Origanum vulgare), (17) peppermint (Mentha x piperita), and (18) thyme (Thymus vulgaris). The team also searched for terms related to protocols, including Dr. Rawls' protocol and the Buhner protocol.

Setting

University of Maryland Medical Center, Baltimore MD.

Results

Seven of the 18 herbs reviewed had evidence for in-vitro activity against B. burgdorferi. These compounds included: (1) cat's claw (2) cryptolepis, (3) Chinese skullcap, (4) Japanese knotweed, (5) sweet wormwood, (6) thyme, and (7) oil of oregano. With the exception of oil of oregano these compounds also have anti-inflammatory activity. In vivo data and clinical trials are lacking. Clinicians should be cautious as many of the identified compounds have drug interactions and additive effects that could lead to increased risks for bleeding, hypotension, and hypoglycemia.

Conclusions

Many of the herbs that alternative and integrative practitioners use to treat Lyme disease have anti-inflammatory effects that may contribute to patients' perceptions of symptomatic improvement. Some herbs have limited demonstrated anti-borrelial activity in vitro, but in-vivo data and clinical trial data is lacking. Further research is required to determine the efficacy, safety and appropriate use of these herbs for this patient population.

Artificial Intelligence Applied to Improve Scientific Reviews: The Antibacterial Activity of Cistus Plants as Proof of Concept

Reviews have traditionally been based on extensive searches of the available bibliography on the topic of interest. However, this approach is frequently influenced by the authors' background, leading to possible selection bias. Artificial intelligence applied to natural language processing (NLP) is a powerful tool that can be used for systematic reviews by speeding up the process and providing more objective results, but its use in scientific literature reviews is still scarce. This manuscript addresses this challenge by developing a reproducible tool that can be used to develop objective reviews on almost every topic. This tool has been used to review the antibacterial activity of Cistus genus plant extracts as proof of concept, providing a comprehensive and objective state of the art on this topic based on the analysis of 1601 research manuscripts and 136 patents. Data were processed using a publicly available Jupyter Notebook in Google Collaboratory here. NLP, when applied to the study of antibacterial activity of Cistus plants, is able to recover the main scientific manuscripts and patents related to the topic, avoiding any biases. The NLP-assisted literature review reveals that C. creticus and C. monspeliensis are the first and second most studied Cistus species respectively. Leaves and fruits are the most commonly used plant parts and methanol, followed by butanol and water, the most widely used solvents to prepare plant extracts. Furthermore, Staphylococcus. aureus followed by Bacillus. cereus are the most studied bacterial species, which are also the most susceptible bacteria in all studied assays. This new tool aims to change the actual paradigm of the review of scientific literature to make the process more efficient, reliable, and reproducible, according to Open Science standards.

Neuropsychiatric Symptoms and Tick-Borne Diseases

In North America, Lyme disease (LD) is primarily caused by the spirochetal bacterium Borrelia burgdorferi, transmitted to humans by Ixodes species tick bites, at an estimated rate of 476,000 patients diagnosed per year. Acute LD often manifests with flu-like symptoms and an expanding rash known as erythema migrans (EM) and less often with neurologic, neuropsychiatric, arthritic, or cardiac features. Most acute cases of Lyme disease are effectively treated with antibiotics, but 10-20% of individuals may experience recurrent or persistent symptoms. This chapter focuses on the neuropsychiatric aspects of Lyme disease, as these are less widely recognized by physicians and often overlooked. Broader education about the potential complexity, severity, and diverse manifestations of tick-borne diseases is needed.

Precision Medicine Approach to Alzheimer's Disease: Rationale and Implications

The neurodegenerative disease field has enjoyed extremely limited success in the development of effective therapeutics. One potential reason is the lack of disease models that yield accurate predictions and optimal therapeutic targets. Standard clinical trials have pre-determined a single treatment modality, which may be unrelated to the primary drivers of neurodegeneration. Recent proof-of-concept clinical trials using a precision medicine approach suggest a new model of Alzheimer's disease (AD) as a chronic innate encephalitis that creates a network insufficiency. Identifying and addressing the multiple potential contributors to cognitive decline for each patient may represent a more effective strategy. Here we review the rationale for a precision medicine approach in prevention and treatment of cognitive decline associated with AD. Results and implications from recent proof-of-concept clinical trials are presented. Randomized controlled trials, with much larger patient numbers, are likely to be significant to establishing precision medicine protocols as a standard of care for prevention and treatment of cognitive decline. Furthermore, combining this approach with the pharmaceutical approach offers the potential for enhanced outcomes. However, incorporating precision medicine approaches into everyday evaluation and care, as well as future clinical trials, would require fundamental changes in trial design, IRB considerations, funding considerations, laboratory evaluation, personalized treatment plans, treatment teams, and ultimately in reimbursement guidelines. Nonetheless, precision medicine approaches to AD, based on a novel model of AD pathophysiology, offer promise that has not been realized to date with monotherapeutic approaches.

Precision Medicine Approach to Alzheimer’s Disease: Successful Pilot Project

Background:

Effective therapeutics for Alzheimer’s disease are needed. However, previous clinical trials have pre-determined a single treatment modality, such as a drug candidate or therapeutic procedure, which may be unrelated to the primary drivers of the neurodegenerative process. Therefore, increasing data set size to include the potential contributors to cognitive decline for each patient, and addressing the identified potential contributors, may represent a more effective strategy.

Objective:

To determine whether a precision medicine approach to Alzheimer’s disease and mild cognitive impairment is effective enough in a proof-of-concept trial to warrant a larger, randomized, controlled clinical trial.

Methods:

Twenty-five patients with dementia or mild cognitive impairment, with Montreal Cognitive Assessment (MoCA) scores of 19 or higher, were evaluated for markers of inflammation, chronic infection, dysbiosis, insulin resistance, protein glycation, vascular disease, nocturnal hypoxemia, hormone insufficiency or dysregulation, nutrient deficiency, toxin or toxicant exposure, and other biochemical parameters associated with cognitive decline. Brain magnetic resonance imaging with volumetrics was performed at baseline and study conclusion. Patients were treated for nine months with a personalized, precision medicine protocol, and cognition was assessed at t = 0, 3, 6, and 9 months.

Results:

All outcome measures revealed improvement: statistically significant improvement in MoCA scores, CNS Vital Signs Neurocognitive Index, and Alzheimer’s Questionnaire Change score were documented. No serious adverse events were recorded. MRI volumetrics also improved.

Conclusion:

Based on the cognitive improvements observed in this study, a larger, randomized, controlled trial of the precision medicine therapeutic approach described herein is warranted.

Extraction and Fractionation of Bioactives from Dipsacus fullonum L. Leaves and Evaluation of Their Anti-Borrelia Activity

Lyme disease (LD) is a tick-borne bacterial disease that is caused by Borrelia burgdorferi. Although acute LD is treated with antibiotics, it can develop into relapsing chronic form caused by latent forms of B. burgdorferi. This leads to the search for phytochemicals against resistant LD. Therefore, this study aimed to evaluate the activity of Dipsacus fullonum L. leaves extract (DE) and its fractions against stationary phase B. burgdorferi in vitro. DE showed high activity against stationary phase B. burgdorferi (residual viability 19.8 ± 4.7%); however, it exhibited a noticeable cytotoxicity on NIH cells (viability 20.2 ± 5.2%). The iridoid-glycoside fraction showed a remarkable anti-Borrelia effect and reduced cytotoxicity. The iridoid-glycoside fraction was, therefore, further purified and showed to contain two main bioactives—sylvestrosides III and IV, that showed a considerable anti-Borrelia activity being the least toxic to murine fibroblast NIH/3T3 cells. Moreover, the concentration of sylvestrosides was about 15% of DE, endorsing the feasibility of purification of the compounds from D. fullonum L. leaves.

Recent Progress in Lyme Disease and Remaining Challenges

Lyme disease (also known as Lyme borreliosis) is the most common vector-borne disease in the United States with an estimated 476,000 cases per year. While historically, the long-term impact of Lyme disease on patients has been controversial, mounting evidence supports the idea that a substantial number of patients experience persistent symptoms following treatment. The research community has largely lacked the necessary funding to properly advance the scientific and clinical understanding of the disease, or to develop and evaluate innovative approaches for prevention, diagnosis, and treatment. Given the many outstanding questions raised into the diagnosis, clinical presentation and treatment of Lyme disease, and the underlying molecular mechanisms that trigger persistent disease, there is an urgent need for more support. This review article summarizes progress over the past 5 years in our understanding of Lyme and tick-borne diseases in the United States and highlights remaining challenges.

Incorporation of grape seed extract towards wound care product development

Naturally derived ingredients are becoming more prevalent in therapeutic drug formulations due to consumers' concerns about chemical side effects. In the context of wound care, despite the impressive progress in therapeutic product development, drugs dispensed to treat impaired healing challenged by biofilms; excessive inflammation and oxidation are not yet really effective. Thus, the hunts for improved drug formulations preferably using natural ingredients that are cost-effective in accelerating the wound-healing process are of constant demand. The grape seed extract is extensively studied and is reported to be rich in phenolic compounds, unsaturated fatty acids and vitamins which exhibit numerous therapeutic benefits owing to their anti-inflammatory, anti-microbial, and anti-oxidative properties that support its potential use in the development of wound-healing products. We conducted a literature study using Scopus, PubMed, and Google Scholar including the keywords "grape seed extract" and "wound healing". We also scanned all the references cited by the retrieved articles. Accordingly, this review is aimed to (i) explore the various phytochemical constituents found in grape seed extracts along with their mechanism of action that instigate wound healing, (ii) to highlight the latest pre-clinical and clinical assessments of grape seed extract in wound models, and (iii) to encourage innovation scientists in the field to address current limitations and to effectively develop grape seed extract-based wound care product formulations for commercialization.

Andrographis paniculata (Burm. f.) Wall. ex Nees: An Updated Review of Phytochemistry, Antimicrobial Pharmacology, and Clinical Safety and Efficacy

Infectious disease (ID) is one of the top-most serious threats to human health globally, further aggravated by antimicrobial resistance and lack of novel immunization options. Andrographis paniculata (Burm. f.) Wall. ex Nees and its metabolites have been long used to treat IDs. Andrographolide, derived from A. paniculata, can inhibit invasive microbes virulence factors and regulate the host immunity. Controlled clinical trials revealed that A. paniculata treatment is safe and efficacious for acute respiratory tract infections like common cold and sinusitis. Hence, A. paniculata, mainly andrographolide, could be considered as an excellent candidate for antimicrobial drug development. Considering the importance, medicinal values, and significant role as antimicrobial agents, this study critically evaluated the antimicrobial therapeutic potency of A. paniculata and its metabolites, focusing on the mechanism of action in inhibiting invasive microbes and biofilm formation. A critical evaluation of the secondary metabolites with the aim of identifying pure compounds that possess antimicrobial functions has further added significant values to this study. Notwithstanding that A. paniculata is a promising source of antimicrobial agents and safe treatment for IDs, further empirical research is warranted.

Polyphenol Diversity and Antioxidant Activity of European Cistus creticus L. (Cistaceae) Compared to Six Further, Partly Sympatric Cistus Species

This investigation focused on the qualitative and quantitative composition of polyphenolic compounds of Mediterranean northern shore Cistus creticus and six further, partly sympatric Cistus species (C. albidus, C. crispus, C. ladanifer, C. monspeliensis, C. parviflorus, C. salviifolius). Aqueous extracts of 1153 individual plants from 13 countries were analyzed via high performance liquid chromatography (HPLC). The extracts of C. creticus were primarily composed of two ellagitannins (punicalagin and punicalagin gallate) and nine flavonol glycosides (myricetin and quercetin glycosides, with m-3-O-rhamnoside as the dominant main compound). Differences in the proportions of punicalagin derivatives and flavonol glycosides allowed the classification into two chemovariants. Plants containing punicalagin derivatives and flavonol glycosides were especially abundant in the western and central Mediterranean areas and in Cyprus. From Albania eastwards, punicalagin and punicalagin gallate were of much lesser importance and the predominant chemovariant there was a nearly pure flavonol type. With its two chemovariants, C. creticus takes a central position between the flavonol-rich, purple-flowered clade (besides C. creticus, here represented by C. albidus and C. crispus) and the more ellagitannin-rich, white- or whitish-pink-flowered clade (here represented by C. ladanifer, C. monspeliensis, C. parviflorus and C. salviifolius). The median antioxidative capacity of C. creticus plant material was, with 166 mg Trolox equivalents/g dry wt, about half of the antioxidative capacity of C. ladanifer (301 mg te/g dry wt), the species with the highest antioxidative potential.

Botanical Medicines Cryptolepis sanguinolenta, Artemisia annua, Scutellaria baicalensis, Polygonum cuspidatum, and Alchornea cordifolia Demonstrate Inhibitory Activity Against Babesia duncani

Human babesiosis is a CDC reportable disease in the United States and is recognized as an emerging health risk in multiple parts of the world. The current treatment for human babesiosis is suboptimal due to treatment failures and unwanted side effects. Although Babesia duncani was first described almost 30 years ago, further research is needed to elucidate its pathogenesis and clarify optimal treatment regimens. Here, we screened a panel of herbal medicines and identified Cryptolepis sanguinolenta, Artemisia annua, Scutellaria baicalensis, Alchornea cordifolia, and Polygonum cuspidatum to have good in vitro inhibitory activity against B. duncani in the hamster erythrocyte model. Furthermore, we found their potential bioactive compounds, cryptolepine, artemisinin, artesunate, artemether, and baicalein, to have good activity against B. duncani, with IC₅₀ values of 3.4 μM, 14 μM, 7.4 μM, 7.8 μM, and 12 μM, respectively, which are comparable or lower than that of the currently used drugs quinine (10 μM) and clindamycin (37 μM). B. duncani treated with cryptolepine and quinine at their respective 1×, 2×, 4× and 8× IC₅₀ values, and by artemether at 8× IC₅₀ for three days could not regrow in subculture. Additionally, Cryptolepis sanguinolenta 90% ethanol extract also exhibited no regrowth after 6 days of subculture at doses of 2×, 4×, and 8× IC₅₀ values. Our results indicate that some botanical medicines and their active constituents have potent activity against B. duncani in vitro and may be further explored for more effective treatment of babesiosis.

Evaluation of Disulfiram Drug Combinations and Identification of Other More Effective Combinations against Stationary Phase Borrelia burgdorferi

Lyme disease, caused by Borrelia burgdorferi, is the most common vector-borne disease in USA, and 10-20% of patients will develop persistent symptoms despite treatment ("post-treatment Lyme disease syndrome"). B. burgdorferi persisters, which are not killed by the current antibiotics for Lyme disease, are considered one possible cause. Disulfiram has shown to be active against B. burgdorferi, but its activity against persistent forms is not well characterized. We assessed disulfiram as single drug and in combinations against stationary-phase B. burgdorferi culture enriched with persisters. Disulfiram was not very effective in the drug exposure experiment (survival rate (SR) 46.3%) or in combinations. Clarithromycin (SR 41.1%) and nitroxoline (SR 37.5%) were equally effective when compared to the current Lyme antibiotic cefuroxime (SR 36.8%) and more active than disulfiram. Cefuroxime + clarithromycin (SR 25.9%) and cefuroxime + nitroxoline (SR 27.5%) were significantly more active than cefuroxime + disulfiram (SR 41.7%). When replacing disulfiram with clarithromycin or nitroxoline in three-drug combinations, bacterial viability decreased significantly and subculture studies showed that combinations with these two drugs (cefuroxime + clarithromycin/nitroxoline + furazolidone/nitazoxanide) inhibited the regrowth, while disulfiram combinations did not (cefuroxime + disulfiram + furazolidone/nitazoxanide). Thus, clarithromycin and nitroxoline should be further assessed to determine their role as potential treatment alternatives in the future.