Synthetic nanoparticle-conjugated bisindoles and hydrazinyl arylthiazole as novel antiamoebic agents against brain-eating amoebae.

Balamuthia mandrillaris and Naegleria fowleri are free-living amoebae that can cause life-threatening infections involving the central nervous system. The high mortality rates of these infections demonstrate an urgent need for novel treatment options against the amoebae. Considering that indole and thiazole compounds possess wide range of antiparasitic properties, novel bisindole and thiazole derivatives were synthesized and evaluated against the amoebae. The antiamoebic properties of four synthetic compounds i.e., two new bisindoles (2-Bromo-4-(di (1H-indol-3-yl)methyl)phenol (denoted as A1) and 2-Bromo-4-(di (1H-indol-3-yl)methyl)-6-methoxyphenol (A2)) and two known thiazole (4-(3-Nitrophenyl)-2-(2-(pyridin-3-ylmethylene)hydrazinyl)thiazole (A3) and 4-(Biphenyl-4-yl)-2-(2-(1-(pyridin-4-yl)ethylidene)hydrazinyl)thiazole (A4)) were evaluated against B. mandrillaris and N. fowleri. The ability of silver nanoparticle (AgNPs) conjugation to enrich antiamoebic activities of the compounds was also investigated. The synthetic heterocyclic compounds demonstrated up to 53% and 69% antiamoebic activities against B. mandrillaris and N. fowleri respectively, while resulting in up to 57% and 68% amoebistatic activities, respectively. Antiamoebic activities of the compounds were enhanced by up to 71% and 51% against B. mandrillaris and N. fowleri respectively, after conjugation with AgNPs. These compounds exhibited potential antiamoebic effects against B. mandrillaris and N. fowleri and conjugation of synthetic heterocyclic compounds with AgNPs enhanced their activity against the amoebae.

Nanoparticles based therapeutic efficacy against Acanthamoeba: Updates and future prospect.

Acanthamoeba sp. is a free living amoeba that causes severe, painful and fatal infections, viz. Acanthamoeba keratitis and granulomatous amoebic encephalitis among humans. Antimicrobial chemotherapy used against Acanthamoeba is toxic to human cells and show side effects as well. Infections due to Acanthamoeba also pose challenges towards currently used antimicrobial treatment including resistance and transformation of trophozoites to resistant cyst forms that can lead to recurrence of infection. Therapeutic agents targeting central nervous system infections caused by Acanthamoeba should be able to cross blood-brain barrier. Nanoparticles based drug delivery put forth an effective therapeutic method to overcome the limitations of currently used antimicrobial chemotherapy. In recent years, various researchers investigated the effectiveness of nanoparticles conjugated drug and/or naturally occurring plant compounds against both trophozoites and cyst form of Acanthamoeba. In the current review, a reasonable effort has been made to provide a comprehensive overview of various nanoparticles tested for their efficacy against Acanthamoeba. This review summarizes the noteworthy details of research performed to elucidate the effect of nanoparticles conjugated drugs against Acanthamoeba.

Minimal Cerebrospinal Fluid Concentration of Miltefosine despite Therapeutic Plasma Levels during the Treatment of Amebic Encephalitis.

Miltefosine is an alkylphosphocholine compound that is used primarily for treatment of leishmaniasis and demonstrates in vitro and in vivo antiamebic activity against Acanthamoeba species. Recommendations for treatment of amebic encephalitis generally include miltefosine therapy. Data indicate that treatment with an amebicidal concentration of at least 16 µg/ml of miltefosine is required for most Acanthamoeba species. Although there is a high level of mortality associated with amebic encephalitis, a paucity of data regarding miltefosine levels in plasma and cerebrospinal fluid in vivo exists in the literature. We found that despite aggressive dosing (oral miltefosine 50 mg every 6 h) and therapeutic plasma levels, the miltefosine concentration in cerebrospinal fluid was negligible in a patient with AIDS and Acanthamoeba encephalitis.

Acanthamoeba endophthalmitis during treatment for cutaneous disease in a renal transplant patient.

Acanthamoeba infections are difficult to diagnose and treat. We present a renal transplant patient who developed Acanthamoeba endophthalmitis on therapy with posaconazole and miltefosine for cutaneous acanthamobiasis. The patient was maintained on intracameral voriconazole injections, and oral azithromycin, fluconazole, and flucytosine. This case highlights novel presentations and treatments for acanthamoebic infection.

Diloxanide furoate binary complexes with ß-, methyl-ß-, and hydroxypropyl-ß-cyclodextrins: inclusion mode, characterization in solution and in solid state and in vitro dissolution studies.

The purpose of this study was to investigate the effect on solubility and dissolution rate of binary complexes of ß-(ßCD), methyl-(MßCD) and hydroxypropyl-ß-cyclodextrin (HPßCD) with diloxanide furoate (DF). The complexation in solution was evaluated by phase solubility studies and 1H nuclear magnetic resonance (NMR). Enhanced water solubility of DF was obtained with the DF:MßCD system (61-fold). The mode of inclusion was supported by NMR experiments, which indicated that real inclusion complexes were formed between DF and MßCD or HPßCD. Solid state analysis was performed using infrared and thermal methods, which suggested the formation of true inclusion complexes of DF with two derivatized cyclodextrins, MßCD and HPßCD, and an exclusion complex with ßCD when the systems were prepared by freeze-dried technique. Dissolution studies conducted in simulated gastric fluid (2 h) and subsequent simulated intestinal fluid (next 4 h) showed increased dissolution rate of DF from the freeze-dried systems with ßCD, MßCD, and HPßCD (85; 77 and 75% of dissolved drug at 5 min, respectively) and 100% of the drug dissolved at 150 min for the three systems. The enhancement of the solubility and the dissolution of DF observed make these complexes promising candidates for the preparation of oral pharmaceutical formulations.

Bioactivity, Safety, and Efficacy of Amphotericin B Nanomicellar Aerosols Using Sodium Deoxycholate Sulfate as the Lipid Carrier.

We report nanomicelles of amphotericin B (AmB) using various molar ratios of AmB and sodium deoxycholate sulfate (SDCS) for inhalation with improved stability, solubility, bioactivity, and safety. The particle sizes of all aerosolized formulations are expressed as mass median aerodynamic diameter (0.9-1.6 µm), fine particle fraction (70.3-86.5%), and geometric standard deviation (1.4-2.1) which indicated their sizes are appropriate for use as an inhaler. In vitro cytotoxicity studies conducted using respiratory and kidney cell lines demonstrated that the marketed Fungizone® was toxic to macrophage and embryonic kidney cells and cell viability decreased from 96 to 48% and from 97 to 67%, respectively when the AmB equivalent concentration was increased from 1 to 16 µg/mL. However, AmB-SDCS formulations showed no evidence of toxicity even up to 8 µg/mL compared to Fungizone®. Minimum inhibitory and fungicidal concentrations were significantly reduced against Cryptococcus neoformans, and Candida albicans. Also, antileishmanial activity significantly improved for AmB-SDCS formulations. There was an evidence of phagocytosis of the AmB-SDCS formulation by alveolar macrophages NR 8383. Molecular modeling studies suggested the role of hydrogen bonding in stabilization of the AmB-SDCS complex. This study indicated that AmB-SDCS nanomicelles can be used to design a safe and cost-effective AmB for inhalation. Graphical abstract ᅟ.

Disseminated Acanthamoeba infection in a heart transplant recipient treated successfully with a miltefosine-containing regimen: Case report and review of the literature.

Disseminated acanthamoebiasis is a rare, often fatal, infection most commonly affecting immunocompromised patients. We report a case involving sinuses, skin, and bone in a 60-year-old woman 5 months after heart transplantation. She improved with a combination of flucytosine, fluconazole, miltefosine, and decreased immunosuppression. To our knowledge, this is the first case of successfully treated disseminated acanthamoebiasis in a heart transplant recipient and only the second successful use of miltefosine for this infection among solid organ transplant recipients. Acanthamoeba infection should be considered in transplant recipients with evidence of skin, central nervous system, and sinus infections that are unresponsive to antibiotics. Miltefosine may represent an effective component of a multidrug therapeutic regimen for the treatment of this amoebic infection.

Assessment of blood-brain barrier penetration of miltefosine used to treat a fatal case of granulomatous amebic encephalitis possibly caused by an unusual Balamuthia mandrillaris strain.

Balamuthia mandrillaris, a free-living ameba, causes rare but frequently fatal granulomatous amebic encephalitis (GAE). Few patients have survived after receiving experimental drug combinations, with or without brain lesion excisions. Some GAE survivors have been treated with a multi-drug regimen including miltefosine, an investigational anti-leishmanial agent with in vitro amebacidal activity. Miltefosine dosing for GAE has been based on leishmaniasis dosing because no data exist in humans concerning its pharmacologic distribution in the central nervous system. We describe results of limited cerebrospinal fluid (CSF) and serum drug level testing performed during clinical management of a child with fatal GAE who was treated with a multiple drug regimen including miltefosine. Brain biopsy specimens, CSF, and sera were tested for B. mandrillaris using multiple techniques, including culture, real-time polymerase chain reaction, immunohistochemical techniques, and serology. CSF and serum miltefosine levels were determined using a liquid chromatography method coupled to tandem mass spectrometry. The CSF miltefosine concentration on hospital admission day 12 was 0.4 µg/mL. The serum miltefosine concentration on day 37, about 80 h post-miltefosine treatment, was 15.3 µg/mL. These are the first results confirming some blood-brain barrier penetration by miltefosine in a human, although with low-level CSF accumulation. Further evaluation of brain parenchyma penetration is required to determine optimal miltefosine dosing for Balamuthia GAE, balanced with the drug's toxicity profile. Additionally, the Balamuthia isolate was evaluated by real-time polymerase chain reaction (PCR), demonstrating genetic variability in 18S ribosomal RNA (18S rRNA) sequences and possibly signaling the first identification of multiple Balamuthia strains with varying pathogenicities.

[Fever and right upper abdominal pain in a 26-year-old returning from travel abroad]. / Fieber und rechtsseitige Oberbauchschmerzen bei einem 26-jährigen Reiserückkehrer.

Persistent fever and unspecific general symptoms need a complete and detailed medical history and search for infection. We report on a case of amebiasis with liver abscesses of a 26-year-old man. He had stayed several weeks in India and South America. After being free of complaints for 4 months, unspecific general symptoms and fever appeared. Due to proven liver abscesses, a combination treatment was given. Within 12 days, he was free of symptoms and could be discharged.

Oral lactoferrin treatment resolves amoebic intracecal infection in C3H/HeJ mice.

Entamoeba histolytica is a protozoan parasite that causes amoebiasis, an illness that affects many people around the world. We have previously reported that lactoferrin is able to kill E. histolytica in in vitro cultures. The aim of the present study was to evaluate the therapeutic effect of orally administered bovine lactoferrin in the control of intestinal amoebiasis of susceptible C3H/HeJ mice. The results showed that 20 mg lactoferrin/kg orally administered each day for 1 week was able to eliminate the infection in 63% of the mice, since neither trophozoites nor evidence of epithelial damage and (or) swelling were found in tissue sections of the cecum. The rest of the treated animals (37%) showed a decrease in trophozoite numbers and mucus secreted to the lumen, as compared with untreated and infected mice (p < 0.05). By immunohistochemistry, the profile of secreted cytokines in the cecum revealed that infected but untreated animals showed a mixed Th1/regulatory cytokines profile, whereas the cecum of mice treated (cured) showed a Th2 cytokine profile (IL-4) and expression of the multifunctional IL-6. In addition, cytokines and increasing cecal production of total IgA antibodies were found associated with little inflammation and disease control observed in the cecum of lactoferrin-treated animals. These results suggest that oral administration of lactoferrin can control intestinal amoebic infection probably by killing amoebas or favoring their removal and reestablish the antiinflammatory intestinal environment.