Identification of FDA-Approved Drugs with Activity against Stationary Phase Bartonella henselae.

Wanliang Shi,Ying Zhang,David Sullivan,Jie Feng,Shuzhen Xiao,Tingting Li

doi:10.3390/antibiotics8020050

Abstract

Bartonella henselae can cause various infections in humans, ranging from benign and self-limiting diseases to severe and life-threatening diseases as well as persistent infections that are difficult to treat. To develop more effective treatments for persistent Bartonella infections, in this study, we performed a high-throughput screen of an FDA-approved drug library against stationary phase B. henselae using the SYBR Green I/propidium iodide (PI) viability assay. We identified 110 drug candidates that had better activity against stationary phase B. henselae than ciprofloxacin, and among the top 52 drug candidates tested, 41 drugs were confirmed by microscopy to have higher activity than the current frontline antibiotic erythromycin. The identified top drug candidates include pyrvinium pamoate, daptomycin, methylene blue, azole drugs (clotrimazole, miconazole, sulconazole, econazole, oxiconazole, butoconazole, bifonazole), aminoglycosides (gentamicin and streptomycin, amikacin, kanamycin), amifostine (Ethyol), antiviral Lopinavir/ritonavir, colistin, nitroxoline, nitrofurantoin, verteporfin, pentamidine, berberine, aprepitant, olsalazine, clinafloxacin, and clofoctol. Pyrvinium pamoate, daptomycin, methylene blue, clotrimazole, and gentamicin and streptomycin at their respective maximum drug concentration in serum (Cmax) had the capacity to completely eradicate stationary phase B. henselae after 3-day drug exposure in subculture studies. While the currently used drugs for treating bartonellosis, including rifampin, erythromycin, azithromycin, doxycycline, and ciprofloxacin, had very low minimal inhibitory concentration (MIC) against growing B. henselae, they had relatively poor activity against stationary phase B. henselae, except aminoglycosides. The identified FDA-approved agents with activity against stationary phase B. henselae should facilitate development of more effective treatments for persistent Bartonella infections.

Highlights

Bartonella species are fastidious Gram-negative intracellular bacteria that are highly adapted to their mammalian reservoir hosts
The SYBR Green I/propidium iodide (PI) assay for rapid viability assessment of B. henselae was carried out as we described previously, which we have successfully used for high throughput drug screens against stationary phase B. burgdorferi [12]
We successfully adapted the SYBR Green/PI viability assay to B. henselae and performed a high throughput screen with FDA-approved drug library for activity against stationary phase B. henselae

Summary

Introduction

Bartonella species are fastidious Gram-negative intracellular bacteria that are highly adapted to their mammalian reservoir hosts. The bacterium can persist in the bloodstream of the host as the results of intraerythrocytic parasitism [3,4], and can cause a wide range of systemic disease such as bacteremia and central nervous system pathologies, especially in immunocompromised individuals [5]. B. henselae is sometimes a co-infection pathogen of Lyme disease transmitted by ticks carrying multiple pathogens causing more severe and protracted clinical manifestations [6]. Treatment of systemic B. henselae infections has been difficult with poor clinical outcomes despite antibiotic treatment for weeks and months [8]. The first-line antibiotics for treatment of Bartonella infections include doxycycline, erythromycin, azithromycin, tetracyclines, gentamicin, rifampin, ciprofloxacin, and sulfa drugs, but most investigators have observed no benefit of antibiotic therapy for the treatment of typical, uncomplicated cat scratch disease [9,10], and effective treatment for Bartonella persistent infections remains a challenge. We successfully used the SYBR Green/PI viability assay for rapid high throughput drug screens for stationary phase

Methods

Results

Discussion

Conclusion