scholarly journals Repurposing the quinoline antibiotic nitroxoline to treat infections caused by the brain-eating amoebaBalamuthia mandrillaris

2018 ◽  
Author(s):  
Matthew T. Laurie ◽  
Corin V. White ◽  
Hanna Retallack ◽  
Wesley Wu ◽  
Matthew S. Moser ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Antimicrobial Agents ◽  
Survival Rates ◽  
Standard Of Care ◽  
Host Cells ◽  
Current Standard ◽  
Promising Candidate ◽  
Balamuthia Mandrillaris ◽  
Tract Infections

AbstractBalamuthia mandrillarisis a pathogenic free-living amoeba that causes a rare but almost always fatal infection of the central nervous system called granulomatous amoebic encephalitis (GAE). Two distinct forms ofB. mandrillaris– a proliferative trophozoite form and a non-proliferative cyst form, which is highly resistant to harsh physical and chemical conditions – have been isolated from environmental samples worldwide and are both observed in infected tissue. Patients suffering from GAE are typically treated with aggressive and prolonged multi-drug regimens often including the antimicrobial agents miltefosine and pentamidine isethionate. However, survival rates remain low and studies evaluating the susceptibility ofB. mandrillaristo these compounds and other potential therapeutics are limited. To address the need for more effective treatments, we screened 2,177 clinically-approved compounds forin vitroactivity againstB. mandrillaris. The quinoline antibiotic nitroxoline, which has safely been used in humans to treat urinary tract infections, was identified as a lead compound. We show that nitroxoline inhibits both trophozoites and cysts at low micromolar concentrations, which are within a physiologically relevant range. We compare thein vitroefficacy of nitroxoline to drugs currently used in the standard of care for GAE and find that nitroxoline is the most potent and selective inhibitor ofB. mandrillaristested. Furthermore, we demonstrate that nitroxoline preventsB. mandrillaris-mediateddestruction of host cells in cultured fibroblast and primary brain explant models also at physiologically relevant concentrations. Together, our findings indicate that nitroxoline is a promising candidate for repurposing as a novel treatment ofB. mandrillarisinfections.ImportanceBalamuthia mandrillarisis responsible for hundreds of reported cases of amoebic encephalitis, the majority of which have been fatal. Despite being an exceptionally deadly pathogen,B. mandrillarisis understudied, leaving many open questions regarding epidemiology, diagnosis, and treatment. Due to the lack of effective drugs to fightB. mandrillarisinfections, mortality rates remain high even for patients receiving intensive care. This study addresses the need for new anti-amoebic drugs using a high-throughput screening approach to identify novelB. mandrillarisinhibitors. The most promising candidate identified was the quinoline antibiotic nitroxoline, which has a long history of safe use in humans. We show that nitroxoline killsB. mandrillarisat physiologically relevant concentrations and exhibits greater potency and selectivity than drugs commonly used in the current standard of care. The findings we present demonstrate the potential of nitroxoline to be an important new tool in the treatment of life threateningB. mandrillarisinfections.

scholarly journals Functional Assessment of 2,177 U.S. and International Drugs Identifies the Quinoline Nitroxoline as a Potent Amoebicidal Agent against the PathogenBalamuthia mandrillaris

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Matthew T. Laurie ◽  
Corin V. White ◽  
Hanna Retallack ◽  
Wesley Wu ◽  
Matthew S. Moser ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Survival Rates ◽  
Standard Of Care ◽  
Host Cells ◽  
Current Standard ◽  
Promising Candidate ◽  
Content Type ◽  
Balamuthia Mandrillaris ◽  
Tract Infections

ABSTRACTBalamuthia mandrillarisis a pathogenic free-living amoeba that causes a rare but almost always fatal infection of the central nervous system called granulomatous amoebic encephalitis (GAE). Two distinct forms ofB. mandrillaris—a proliferative trophozoite form and a nonproliferative cyst form, which is highly resistant to harsh physical and chemical conditions—have been isolated from environmental samples worldwide and are both observed in infected tissue. Patients suffering from GAE are typically treated with aggressive and prolonged multidrug regimens that often include the antimicrobial agents miltefosine and pentamidine isethionate. However, survival rates remain low, and studies evaluating the susceptibility ofB. mandrillaristo these compounds and other potential therapeutics are limited. To address the need for more-effective treatments, we screened 2,177 clinically approved compounds forin vitroactivity againstB. mandrillaris. The quinoline antibiotic nitroxoline (8-hydroxy-5-nitroquinoline), which has safely been used in humans to treat urinary tract infections, was identified as a lead compound. We show that nitroxoline inhibits both trophozoites and cysts at low micromolar concentrations, which are within a pharmacologically relevant range. We compared thein vitroefficacy of nitroxoline to that of drugs currently used in the standard of care for GAE and found that nitroxoline is the most potent and selective inhibitor ofB. mandrillaristested. Furthermore, we demonstrate that nitroxoline preventsB. mandrillaris-mediated destruction of host cells in cultured fibroblast and primary brain explant models also at pharmacologically relevant concentrations. Taken together, our findings indicate that nitroxoline is a promising candidate for repurposing as a novel treatment ofB. mandrillarisinfections.IMPORTANCEBalamuthia mandrillarisis responsible for hundreds of reported cases of amoebic encephalitis, the majority of which have been fatal. Despite being an exceptionally deadly pathogen,B. mandrillarisis understudied, leaving many open questions regarding epidemiology, diagnosis, and treatment. Due to the lack of effective drugs to fightB. mandrillarisinfections, mortality rates remain high even for patients receiving intensive care. This report addresses the need for new treatment options through a drug repurposing screen to identify novelB. mandrillarisinhibitors. The most promising candidate identified was the quinoline antibiotic nitroxoline, which has a long history of safe use in humans. We show that nitroxoline killsB. mandrillarisat pharmacologically relevant concentrations and exhibits greater potency and selectivity than drugs commonly used in the current standard of care. The findings that we present demonstrate the potential of nitroxoline to be an important new tool in the treatment of life-threateningB. mandrillarisinfections.

scholarly journals Fur Represses Adhesion to, Invasion of, and Intracellular Bacterial Community Formation within Bladder Epithelial Cells and Motility in Uropathogenic Escherichia coli

2016 ◽  
Vol 84 (11) ◽  
pp. 3220-3231 ◽  
Author(s):  
Kumiko Kurabayashi ◽  
Tomohiro Agata ◽  
Hirofumi Asano ◽  
Haruyoshi Tomita ◽  
Hidetada Hirakawa
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Antimicrobial Agents ◽  
Host Cells ◽  
Type I ◽  
Wild Type ◽  
Content Type ◽  
Type I Fimbriae ◽  
Tract Infections

Uropathogenic Escherichia coli (UPEC) is a major pathogen that causes urinary tract infections (UTIs). This bacterium adheres to and invades the host cells in the bladder, where it forms biofilm-like polymicrobial structures termed intracellular bacterial communities (IBCs) that protect UPEC from antimicrobial agents and the host immune systems. Using genetic screening, we found that deletion of the fur gene, which encodes an iron-binding transcriptional repressor for iron uptake systems, elevated the expression of type I fimbriae and motility when UPEC was grown under iron-rich conditions, and it led to an increased number of UPEC cells adhering to and internalized in bladder epithelial cells. Consequently, the IBC colonies that the fur mutant formed in host cells were denser and larger than those formed by the wild-type parent strain. Fur is inactivated under iron-restricted conditions. When iron was depleted from the bacterial cultures, wild-type UPEC adhesion, invasion, and motility increased, similar to the case with the fur mutant. The purified Fur protein bound to regions upstream of fimA and flhD , which encode type I fimbriae and an activator of flagellar expression that contributes to motility, respectively. These results suggest that Fur is a repressor of fimA and flhD and that its repression is abolished under iron-depleted conditions. Based on our in vitro experiments, we conclude that UPEC adhesion, invasion, IBC formation, and motility are suppressed by Fur under iron-rich conditions but derepressed under iron-restricted conditions, such as in patients with UTIs.

scholarly journals In Vitro Screening of the Open-Source Medicines for Malaria Venture Malaria and Pathogen Boxes To Discover Novel Compounds with Activity against Balamuthia mandrillaris

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Christopher A. Rice ◽  
Luis Fernando Lares-Jiménez ◽  
Fernando Lares-Villa ◽  
Dennis E. Kyle
Keyword(s):  
Open Source ◽  
Single Point ◽  
Standard Of Care ◽  
Current Standard ◽  
Content Type ◽  
Cutaneous Infections ◽  
Balamuthia Mandrillaris ◽  
Free Living Amoeba ◽  
Malaria Box

ABSTRACT Balamuthia mandrillaris is an under-reported, pathogenic free-living amoeba that causes Balamuthia amoebic encephalitis (BAE) and cutaneous skin infections. Although cutaneous infections are not typically lethal, BAE with or without cutaneous involvement is usually fatal. This is due to the lack of drugs that are both efficacious and can cross the blood-brain barrier. We aimed to discover new leads for drug discovery by screening the open-source Medicines for Malaria Venture (MMV) Malaria Box and MMV Pathogen Box, with 800 compounds total. From an initial single point screen at 1 and 10 μM, we identified 54 hits that significantly inhibited the growth of B. mandrillaris in vitro. Hits were reconfirmed in quantitative dose-response assays and 23 compounds (42.6%) were confirmed with activity greater than miltefosine, the current standard of care.

Analogs of marinopyrrole A show enhancement to observed in vitro potency against acute Toxoplasma gondii infection

2021 ◽  
Author(s):  
Matthew C. Martens ◽  
Yan Liu ◽  
Austin G. Sanford ◽  
Alexander I. Wallick ◽  
Rosalie C. Warner ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Acute Infection ◽  
Standard Of Care ◽  
Host Cells ◽  
Infection Model ◽  
Current Standard ◽  
Clinical Consequences ◽  
Toxoplasma Gondii Infection

The apicomplexan parasite Toxoplasma gondii is the causative agent of toxoplasmosis, a globally distributed infection with severe clinical consequences for immunocompromised individuals and developing fetuses. There are few available treatments, and these are associated with potentially severe adverse effects. Marinopyrrole A, a compound discovered in a marine Streptomyces species, has previously been found to exhibit potent antimicrobial activity, prompting our interest in exploring efficacy against Toxoplasma gondii . We found that marinopyrrole A was a highly potent anti- Toxoplasma molecule, with an in vitro 50% maximal inhibitory concentration (IC 50 ) of 0.31 μM corresponding to a higher potency than that of the current standard of care (pyrimethamine); however, addition of 20% serum led to abrogation of potency, and toxicity to human cell lines was observed. Yet, application of marinopyrrole A to an in vivo lethal acute infection model facilitated significantly enhanced survival at doses of 5, 10, and 20 mg/kg. We then tested a series of marinopyrrole A analogs—RL002, RL003, and RL125—demonstrating significantly increased potency in vitro , with IC 50 values ranging from 0.09-0.17 μM (3.6-6.8X increase relative to pyrimethamine). No detectable cytotoxicity was observed up to 50 μM in human foreskin fibroblasts, with cytotoxicity in HepG2 cells ranging from ∼28-50 μM, corresponding to >200X selectivity for parasites over host cells. All analogs additionally showed reduced sensitivity to serum. Further, RL003 potently inhibited in vitro -generated bradyzoites at 0.245 μM. Taken together, these data support further development of marinopyrrole A analogs as promising anti- Toxoplasma molecules to further combat this prevalent infection.

A Generally Applicable, High-Throughput Screening–Compatible Assay to Identify, Evaluate, and Optimize Antimicrobial Agents for Drug Therapy

2004 ◽  
Vol 9 (7) ◽  
pp. 578-587 ◽  
Author(s):  
Gerald Kleymann ◽  
Hans-Otto Werling
Keyword(s):  
Drug Discovery ◽  
High Throughput Screening ◽  
Antimicrobial Agents ◽  
Natural Infection ◽  
Test System ◽  
Test Method ◽  
Host Cells ◽  
Lethal Challenge ◽  
Compound Libraries

Efficacy and tolerability are the key criteria for a successful medication in the clinic. Therefore, a new test method to obtain selective and active lead molecules has been developed. Recently, this novel screening strategy enabled a breakthrough in drug discovery in the field of herpes viruses. Here the authors report that this assay is a generally applicable screening test, which allows not only for identifying tolerable and potent antimicrobial agents in compound libraries, but also covers all potential in vitro targets of both the pathogen and the host simultaneously. The test system mimics the smallest unit of a natural infection. Host cells are incubated in the presence of the test sample and are infected with microbes, such as viruses, bacteria, or fungi. Analogous to (lethal challenge) animal models, cell survival is determined. This assay maximizes the chances of success of anti-infective drug discovery, is sensitive, robust, time- and cost-efficient, and especially effective in optimizing screening hits to lead structures and development candidates. In addition to the minimal inhibitory concentration or dose, this test system simultaneously provides the selectivity index, a measure of tolerability in vitro. The authors propose the activity selectivity assay format as a new standard in anti-infective drug discovery and clinical development.

scholarly journals Antitumor Activity of Nanoparticles Loaded with PHT-427, a Novel AKT/PDK1 Inhibitor, for the Treatment of Head and Neck Squamous Cell Carcinoma

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1242
Author(s):  
Joaquín Yanes-Díaz ◽  
Raquel Palao-Suay ◽  
María Rosa Aguilar ◽  
Juan Ignacio Riestra-Ayora ◽  
Antonio Ferruelo-Alonso ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Head And Neck ◽  
Squamous Cell ◽  
Polymeric Nanoparticles ◽  
Growth Factor Receptor ◽  
Standard Of Care ◽  
Neck Squamous Cell Carcinoma ◽  
Current Standard

Currently, new treatments are required to supplement the current standard of care for head and neck squamous cell carcinoma (HNSCC). The phosphatidylinositol3-kinase (PI3K) signaling pathway is commonly altered and activated in HNSCC. PHT-427 is a dual PI3K-mammalian target of the AKT/PDK1 inhibitor; however, to the best of our knowledge, the effect of the PHT-427 inhibitor on HNSCC has not been investigated. This study aims to evaluate the antitumoral effect of PHT-427-loaded polymeric nanoparticles based on α-tocopheryl succinate (α-TOS). The in vitro activity of PHT-427 was tested in hypopharynx carcinoma squamous cells (FaDu) to measure the cell viability, PI3KCA/AKT/PDK1 gene expression, and PI3KCA/AKT/PDK1 levels. Apoptosis, epidermal growth factor receptor (EGFR), and reactive oxygen species (ROS) were also measured. The presence of PHT-427 significantly enhances its antiproliferative and proapoptotic activity by inactivating the PI3K/AKT/PDK1 pathway. Nanoparticles (NPs) effectively suppress AKT/PDK1 expression. Additionally, NPs loaded with PHT-427 produce high oxidative stress levels that induce apoptosis. In conclusion, these results are promising in the use of this nanoformulation as a PHT-427 delivery system for effective HNSCC treatment.

scholarly journals Urinary infection in dogs with chronic kidney disease: aetiology and resistance

2019 ◽  
Vol 40 (6Supl3) ◽  
pp. 3741
Author(s):  
Ariane Martins Fernandes ◽  
Alessandra Tammy Hayakawa Ito de Sousa ◽  
Luciana Auxiliadora Viebrantz da Conceição ◽  
Felipe Gomes da Silva ◽  
Mayara Aparecida Araújo Cayuela ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Urine Culture ◽  
Urinary Infection ◽  
Clinical Routine ◽  
Disease Aetiology ◽  
Tract Infections ◽  
And Control

Infections of the genitourinary system are among the most frequent in the clinical routine of small animals. Treatment with the most appropriate antimicrobial therapy, according to the uropathogen susceptibility test, can avoid the spread of bacterial resistance to antimicrobials. A clinical study was performed in 32 canines, of both sexes and differing ages, who attended the Veterinary Teaching Hospital. Urine samples underwent culture, with the objective of evaluating urinary tract infection in dogs with renal disease, identifying the associated bacterial pathogens, and verifying their antimicrobial susceptibility in vitro. Urine culture was positive in 10 dogs, mostly males, with no predisposition for breed, and a mean age of 8.28 years. Most of the urinary tract infections (UTIs) were monobacterial, with the most common microorganisms being Pseudomonas sp. and Staphylococcus sp. The antimicrobials imipenem and meropenem had the best overall sensitivity profile, and ampicillin showed the highest resistance. The variation in epidemiological profiles, and susceptibility to uropathogens, reinforces the importance of the veterinarian in the prevention and control of infection, in addition to the need for further research to identify new antimicrobial agents.

Cephazolin Sodium—An In Vivo and In Vitro Evaluation of 100 Patients with Urinary Tract Infections

1975 ◽  
Vol 20 (5) ◽  
pp. 259-260
Author(s):  
Diana M. D. Rimmer
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
General Hospital ◽  
Urinary Tract Infections ◽  
Antimicrobial Agents ◽  
Random Group ◽  
Tract Infections

A random group of 100 patients in a general hospital were treated with cephazolin sodium for proven urinary tract infections. Sixty-six per cent had conditions predisposing to urinary tract infection. Under these somewhat difficult conditions the original infecting organism remained absent from the urine of 75 per cent of the 70 patients followed in the 3rd to 6th week period. This compares very favourably with response to other antimicrobial agents currently used in urinary tract infections.

Novel Neonatal Umbilical Catheter Protection and Stabilization Device in In vitro Model of Catheterized Human Umbilical Cords: Effect of Material and Venting on Bacterial Colonization

2019 ◽  
Author(s):  
Lauren S. Y. Wood ◽  
Janene H. Fuerch ◽  
Carl L. Dambkowski ◽  
Eric F. Chehab ◽  
Shivani Torres ◽  
...  
Keyword(s):  
Bacterial Colonization ◽  
Bacterial Load ◽  
Standard Of Care ◽  
Adhesive Tape ◽  
Human Umbilical Cord ◽  
Current Standard ◽  
Central Lines ◽  
Umbilical Cords

Abstract Objective Umbilical central lines deliver life-saving medications and nutrition for neonates; however, complications associated with umbilical catheters (UCs) occur more frequently than in adults with central lines (i.e., line migration, systemic infection). We have developed a device for neonatal UC protection and stabilization to reduce catheter exposure to bacteria compared with the standard of care: “goal post” tape configuration. This study analyzes the effect of device venting and material on bacterial load of human umbilical cords in vitro. Study Design Catheters were inserted into human umbilical cord segments in vitro, secured with plastic or silicone vented prototype versus tape, and levels of bacterial colonization were compared between groups after 7 days of incubation. Results Nonvented plastic prototype showed increased bacterial load compared with goal post (p = 0.04). Colonization was comparable between the goal post and all vented plastic prototypes (p ≥ 0.30) and when compared with the vented silicone device (p = 1). Conclusion A novel silicone device does not increase external bacterial colonization compared with the current standard of care for line securement, and may provide a safe, convenient alternative to standard adhesive tape for UC stabilization. Future studies are anticipated to establish safety in vivo, alongside benefits such as migration and infection reduction.

scholarly journals CD99 Expression in Glioblastoma Molecular Subtypes and Role in Migration and Invasion

2019 ◽  
Vol 20 (5) ◽  
pp. 1137 ◽  
Author(s):  
Lais Cardoso ◽  
Roseli Soares ◽  
Talita Laurentino ◽  
Antonio Lerario ◽  
Suely Marie ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Molecular Subtypes ◽  
Transmembrane Protein ◽  
Standard Of Care ◽  
Actin Dynamics ◽  
In Vitro Assays ◽  
Migration And Invasion ◽  
Current Standard ◽  
Tumor Cell Migration

Glioblastoma (GBM) is the most aggressive type of brain tumor, with an overall survival of 17 months under the current standard of care therapy. CD99, an over-expressed transmembrane protein in several malignancies, has been considered a potential target for immunotherapy. To further understand this potentiality, we analyzed the differential expression of its two isoforms in human astrocytoma specimens, and the CD99 involved signaling pathways in glioma model U87MG cell line. CD99 was also analyzed in GBM molecular subtypes. Whole transcriptomes by RNA-Seq of CD99-siRNA, and functional in vitro assays in CD99-shRNA, that are found in U87MG cells, were performed. Astrocytoma of different malignant grades and U87MG cells only expressed CD99 isoform 1, which was higher in mesenchymal and classical than in proneural GBM subtypes. Genes related to actin dynamics, predominantly to focal adhesion, and lamellipodia/filopodia formation were down-regulated in the transcriptome analysis, when CD99 was silenced. A decrease in tumor cell migration/invasion, and dysfunction of focal adhesion, were observed in functional assays. In addition, a striking morphological change was detected in CD99-silenced U87MG cells, further corroborating CD99 involvement in actin cytoskeleton rearrangement. Inhibiting the overexpressed CD99 may improve resectability and decrease the recurrence rate of GBM by decreasing tumor cells migration and invasion.

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