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

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.

Essential Oils with High Activity against Stationary Phase Bartonella henselae

“…Based on the culture medium developed in a previous study [57], B. henselae JK53 was cultured in Schneider's Drosophila medium (Life Technologies Limited, Paisley, UK) supplemented with 10% fetal bovine serum (FBS) (Sigma-Aldrich, Co., St. Louis, MO, USA) and 5% sucrose (Fisher Scientific, New Jersey, USA) in microaerophilic incubator without shaking at 37°C, 5% CO 2 . As previously measured [24], B. henselae JK53 rapidly went into the logarithmic growth phase and reached a growth peak after two days under such culture conditions. The one-day-old and five-day-old culture were considered as log phase and stationary phase, respectively.…”

“…Previously, we have developed an SYBR Green I/PI viability assay for the rapid viability assessment of B. henselae and have successfully used this assay for high-throughput drug screens against non-growing stationary phase B. henselae using the FDA drug library [24]. Here we adapted this SYBR Green I/PI viability assay for essential oil screens against B. henselae.…”

“…were included as control drugs for comparison (Table 1). In addition, we included previously identified FDA-approved drugs that were effective against B. henselae such as daptomycin, methylene blue, miconazole and nitrofurantoin [24] as controls ( Table 1). All these antibiotics were used at 20 µM.…”

“…The green/red (538 nm/650 nm) fluorescence ratio of each well was used for calculating the residual viability percentage. With the least-square fitting analysis, the regression equation and regression curve of the relationship between residual viability percentage and green/red fluorescence ratio was obtained, which was used in the calculation as described previously [24]. All tests were run in triplicate.…”

Identification of pyrvinium pamoate as an anti-tuberculosis agent in vitro and in vivo by SOSA approach amongst known drugs

“…We speculated that PP inhibited the growth of M. tb by suppressing NAD+/NADH conversion within the bacteria, but this requires further experimental validation. Recently, some studies reported that PP had pharmacological activity to inhibit the growth of Bartonella henselae infection [32] and coronaviruses replication in vitro [33,34]. PP has also been reported to have anti-tumor activity [28,[34][35][36][37].…”