Parasitic infections have remained a significant burden on human and animal health. In part, this is due to lack of clinically-approved, novel antimicrobials and a lack of interest by the pharmaceutical industry. An alternative approach is to modify existing clinically-approved drugs for efficient delivery formulations to ensure minimum inhibitory concentration is achieved at the target site. Nanotechnology offers the potential to enhance the therapeutic efficacy of drugs through modification of nanoparticles with ligands. Amphotericin B, nystatin, and fluconazole are clinically available drugs in the treatment of amoebal and fungal infections. These drugs were conjugated with gold nanoparticles. To characterize these gold-conjugated drug, atomic force microscopy, ultraviolet-visible spectrophotometry and Fourier transform infrared spectroscopy were performed. These drugs and their gold nanoconjugates were examined for antimicrobial activity against the protist pathogen, Acanthamoeba castellanii of the T4 genotype. Moreover, host cell cytotoxicity assays were accomplished. Cytotoxicity of these drugs and drug-conjugated gold nanoparticles was also determined by lactate dehydrogenase assay. Gold nanoparticles conjugation resulted in enhanced bioactivity of all three drugs with amphotericin B producing the most significant effects against Acanthamoeba castellanii (p ＜ 0.05). In contrast, bare gold nanoparticles did not exhibit antimicrobial potency. Furthermore, amoebae treated with drugs-conjugated gold nanoparticles showed reduced cytotoxicity against HeLa cells. In this report, we demonstrated the use of nanotechnology to modify existing clinically-approved drugs and enhance their efficacy against pathogenic amoebae. Given the lack of development of novel drugs, this is a viable approach in the treatment of neglected diseases.
Sporotrichosis is a subcutaneous fungal infection caused by a thermally dimorphic aerobic fungus, Sporothrix schenckii. It results from traumatic inoculation or contact with animals. Most cases were reported mainly in the tropics and subtropics.
Matched MeSH terms: Amphotericin B/therapeutic use
We aimed to investigate the effects that natural lipids, theobroma oil (TO) and beeswax (BW), might have on the physical properties of formulated nanoparticles and also the degree of expulsion of encapsulated amphotericin B (AmB) from the nanoparticles during storage. Lecithin and sodium cholate were used as emulsifiers whilst oleic acid (OA) was used to study the influence of the state of orderliness/disorderliness within the matrices of the nanoparticles on the degree of AmB expulsion during storage. BW was found to effect larger z-average diameter compared with TO. Lecithin was found to augment the stability of the nanoparticles imparted by BW and TO during storage. An encapsulation efficiency (%EE) of 59% was recorded when TO was the sole lipid as against 42% from BW. In combination however, the %EE dropped to 39%. When used as sole lipid, TO or BW formed nanoparticles with comparatively higher enthalpies, 21.1 and 23.3 J/g respectively, which subsequently caused significantly higher degree of AmB expulsion, 81 and 83% respectively, whilst only 11.8% was expelled from a binary TO/BW mixture. A tertiary TO/BW/OA mixture registered the lowest enthalpy at 8.07 J/g and expelled 12.6% of AmB but encapsulated only 22% of AmB. In conclusion, nanoparticles made from equal concentrations of TO and BW produced the most desirable properties and worthy of further investigations.
Oral delivery of amphotericin B (AmpB) is desirable because it provides a more patient-friendly mode of administration compared to the current delivery approach akin with the marketed AmpB formulations. The goal of the study was to investigate the pharmacokinetics and tissue distribution of orally administered chitosan-coated AmpB-loaded nanostructured lipid carriers (ChiAmpB NLC) administered to Sprague Dawley rats at a dose of 15 mg/kg. Orally administered ChiAmpB NLC resulted in a two-fold increase in the area under the curve (AUC0-∞) compared to the uncoated AmpB NLC and marketed Amphotret®. This enhanced bioavailability of AmpB suggests prolonged transit and retention of ChiAmpB NLC within the small intestine through mucoadhesion and subsequent absorption by the lymphatic pathway. The results show that mean absorption and residence times (MAT & MRT) were significantly higher from ChiAmpB NLC compared to the other two formulations, attesting to the mucoadhesive effect. The ChiAmpB NLC presented a lower nephrotic accumulation with preferential deposition in liver and spleen. Thus, the limitations of current marketed IV formulations of AmpB are potentially addressed with the ChiAmpB NLC in addition to utilizing this approach for targeting internal organs in visceral leishmaniasis.
This study describes the properties of an amphotericin B-containing mucoadhesive nanostructured lipid carrier (NLC), with the intent to maximize uptake within the gastrointestinal tract. We have reported previously that lipid nanoparticles can significantly improve the oral bioavailability of amphotericin B (AmpB). On the other hand, the aggregation state of AmpB within the NLC has been ascribed to some of the side effects resulting from IV administration. In the undissolved state, AmpB (UAmpB) exhibited the safer monomeric conformation in contrast to AmpB in the dissolved state (DAmpB), which was aggregated. Chitosan-coated NLC (ChiAmpB NLC) presented a slightly slower AmpB release profile as compared to the uncoated formulation, achieving 26.1% release in 5 hours. Furthermore, the ChiAmpB NLC formulation appeared to prevent the expulsion of AmpB upon exposure to simulated gastrointestinal pH media, whereby up to 63.9% of AmpB was retained in the NLC compared to 56.1% in the uncoated formulation. The ChiAmpB NLC demonstrated mucoadhesive properties in pH 5.8 and 6.8. Thus, the ChiAmpB NLC formulation is well-primed for pharmacokinetic studies to investigate whether delayed gastrointestinal transit may be exploited to improve the systemic bioavailability of AmpB, whilst simultaneously addressing the side-effect concerns of AmpB.
Surface-modified nanostructured lipid carriers (NLC) represent a promising mode of drug delivery used to enhance retention of drugs at absorption site. Formulated chitosan-coated amphotericin-B-loaded NLC (ChiAmp NLC) had a size of 394.4 ± 6.4 nm, encapsulation and loading efficiencies of 86.0 ± 3% and 11.0 ± 0.1% respectively. Amphotericin-B release from NLCs was biphasic with no changes in physical properties upon exposure to simulated gastrointestinal conditions. Antifungal properties of Amphotericin-B and ChiAmpB NLC were comparable but ChiAmpB NLC was twice less toxic to red blood cells and ten times safer on HT-29 cell lines. In vitro mucoadhesion data were observed ex vivo, where ChiAmpB NLC resulted in higher retention within the small intestine compared to the uncoated formulation. The data strongly offers the possibility of orally administering a non-toxic, yet effective Amphotericin-B nanoformulation for the treatment of systemic fungal infections.
In the fungal pathogen Aspergillus fumigatus, resistance to azole antifungals is often linked to mutations in CYP51A, a gene that encodes the azole antifungal drug target lanosterol 14α-demethylase. The aim of this study was to investigate whether similar changes could be associated with azole resistance in a Malaysian Fusarium solani species complex (FSSC) isolate collection. Most (11 of 15) clinical FSSC isolates were Neocosmospora keratoplastica and the majority (6 of 10) of environmental isolates were Neocosmospora suttoniana strains. All 25 FSSC isolates had high minimum inhibitory concentrations (MICs) for itraconazole and posaconazole, low MICs for amphotericin B, and various (1 to >32 mg/l) voriconazole susceptibilities. There was a tight association between a 23 bp CYP51A promoter deletion and high (>32 mg/l) voriconazole MICs; of 19 FSSC strains sequenced, nine isolates had voriconazole MICs > 32 mg/l, and they all contained the 23 bp CYP51A promoter deletion, although it was absent in the ten remaining isolates with low (≤12 mg/l) voriconazole MICs. Surprisingly, this association between voriconazole resistance and the 23 bp CYP51A promoter deletion held true across species boundaries. It was randomly distributed within and across species boundaries and both types of FSSC isolates were found among environmental and clinical isolates. Three randomly selected N. keratoplastica isolates with low (≤8 mg/l) voriconazole MICs had significantly lower (1.3-7.5 times) CYP51A mRNA expression levels than three randomly selected N. keratoplastica isolates with high (>32 mg/l) voriconazole MICs. CYP51A expression levels, however, were equally strongly induced (~6,500-fold) by voriconazole in two representative strains reaching levels, after 80 min of induction, that were comparable to those of CYP51B. Our results suggest that FSSC isolates with high voriconazole MICs have a 23 bp CYP51A promoter deletion that provides a potentially useful marker for voriconazole resistance in FSSC isolates. Early detection of possible voriconazole resistance is critical for choosing the correct treatment option for patients with invasive fusariosis.
The gastrointestinal (GI) transit behavior of and absorption from an amphotericin B (AmB) solid lipid nanoformulation (SLN) in rats was investigated. We aimed to estimate the gastric emptying time (GET) and cecal arrival time (CAT) of AmB SLN in rats as animal models. From these two parameters, an insight on the absorption window of AmB was ascertained. Three types of SLNs, AmB, paracetamol (PAR), and sulfasalazine (SSZ), were similarly formulated using beeswax/theobroma oil composite as the lipid matrix and characterized with regard to size, viscosity, density, migration propensity within agarose gel, in vitro drug release, morphology, gastrointestinal transit, and in vivo absorption. The GET and CAT were estimated indirectly using marker drugs: PAR and sulfapyridine (SP). All three types of SLNs exhibited identical properties with regard to z-average, viscosity, relative density, and propensity to migrate. PAR was absorbed rapidly from the small intestine following emptying of the SLNs giving the T50E (time for 50% absorption of PAR) to be 1.6 h. SP was absorbed after release and microbial degradation of SSZ from SLN in the colon with a lag time of 2 h post-administration, serving as the estimated cecal arrival time of the SLNs. AmB within SLN was favorably absorbed from the small intestine, albeit slowly.
Introduction: One of the most common aetiology of opportunistic fungal infections in humans is Candida species. The virulence of Candida species is due to repertoire of factors, specifically, the ability to form biofilms. Medical devices such as intravenous catheters, prosthetic heart valves and surgical interventions provide pathogenic microorganisms with a surface to adhere to form biofilm. Fungi present as biofilms are often resistant to antifungal treatment because these biofilms offer a protective barrier that prohibits the drugs to get to the active site of the fungi. The objective of this study is to investigate the biofilm architecture of Candida rugosa (C.rugosa) at different developmental phases and to identify Sessile Minimum Inhibition Concentrations (SMICs) of amphotericin B, caspofungin, fluconazole, and voriconazole for the biofilm of C. rugosa. Methods: Confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM) were used to visualize C. rugosa biofilms at different developmental phases. The antifungal susceptibility test was performed using serial doubling dilution. The growth kinetics of Candida biofilms was quantified using XTT reduction assay and crystal violet assay. Results: From the antifungal susceptibility test, the biofilms had SMIC of >16μg/mL for amphotericin B, 6µg/mL for caspofungin, >64μg/mL for fluconazole and >16μg/ mL for voriconazole. From the SEM micrographs, C. rugosa biofilm have a structure composed of an adherent yeast cells and blastopores with hyphal elements. There were significant alterations in the morphology after exposure to antifungal agents. The quantitative measurement of the matrix thickness of embedded yeast cells were obtained from CLSM micrographs. Conclusion: In conclusion, the ability of C. rugosa to form biofilms may attribute to one of the virulence factors that causes reduced susceptibility to antifungal agents.
We describe here a case of cryptococcal empyema thoracis and periauricular pyogenic abscess in a child with Bruton's agammaglobulinaemia. The cryptococcal empyema thoracis was treated with intravenous amphotericin B and intravenous fluconazole for six weeks followed by oral fluconazole. The pyogenic periauricular abscess was surgically drained and treated with intravenous ceftazidime and cloxacillin for two weeks. He also received monthly intravenous immunoglobulin.
Talaromycosis typically occurs as an opportunistic infection among immunocompromised individuals. Infection caused by species other than T. marneffei is uncommon. While most reported cases describe infection in the lungs, we report an extremely rare intracranial Talaromyces species infection. This 61-year-old with end-stage renal disease who was unwell for the previous two months, presented with fever and worsening confusion lasting for three days. Lumbar puncture was suggestive of meningitis. Cerebrospinal fluid (CSF) culture was later confirmed to be Penicillium chrysogenum. The patient was co-infected with Group B Streptococcus sepsis. He improved with amphotericin B and ceftriaxone and was discharged with oral itraconazole for four weeks. However, he died of unknown causes two weeks later at home. Talaromyces species infection in the central nervous system is uncommon. This case highlighted a rare but life-threatening fungal meningitis. Among the four reported cases worldwide, none of the patients survived.
Pulmonary cryptococcosis can be clinically silent in non-HIV infected patients but can also present as nodules and masses on the chest radiograph, which can be mistaken for tuberculosis or lung cancer. Common symptoms include fever and cough, and uncommonly haemoptysis. This report illustrates a non-HIV infected patient whose main complaint was haemoptysis and headache. He was diagnosed with pulmonary cryptococcosis from biopsy of an endobronchial mass found on flexible bronchoscopy. Disseminated cryptoccoccal infection should be considered as a differential diagnosis in non-HIV infected patients presenting with haemoptysis and headache. Early recognition and administration of appropriate therapy will improve clinical outcome in these patients.
Matched MeSH terms: Amphotericin B/therapeutic use
The in vitro susceptibilities of Malaysian clinical isolates of Cryptococcus neoformans var. grubii and C . gattii to five antifungal drugs (amphotericin B, flucytosine, fluconazole, itraconazole and ketoconazole) were determined using the Etest method. None of the Malaysian isolates was resistant to amphotericin B and ketoconazole. Isolates resistant to flucytosine, fluconazole and itraconazole were observed in this study. Minimum inhibition concentrations (MICs) of > or = 32 microg ml(-1) against flucytosine, > or = 64 microg ml(-1) against fluconazole and > or = 1 microg ml(-1) against itraconazole were noted in four (8.3%), two (4.2%) and one (2.1%) isolates respectively. There was no significant difference in the MICs for both Cryptococcus species (P > 0.05), indicating that C. gattii was as susceptible as var. grubii to all the antifungal drugs tested. No significant difference in the MICs for both Cryptococcus species collected from 1980 to 1990 and 2002 to 2004 were observed (P > 0.05).
Cryptococcosis is a life-threatening mycosis typically seen in immunocompromised patients. Pulmonary cryptococcosis generally presents as multiple or solitary nodular opacities. Cryptococcal infection presenting as a destructing cavernoma (cryptococcoma) without diffuse infiltration of the lung is an extremely rare presentation, even in immunocompromised patients. This report presents a healthy, HIV negative, immunocompetent patient who presented with a large solitary lung mass provisionally diagnosed as a lung malignancy on radiological imaging that proved to be a large cryptococcoma after biopsy. The patient was treated with liposomal Amphotericin B and fluconazole, and the lesion showed regression on serial imaging. This case report thus highlights an unconventional presentation of pulmonary cryptococcosis in an immunocompetent individual.
Mucormycosis is a rare fungal infection and high mortality that commonly affects patients with the weakened immune system. We present an unusual case of tongue necrosis probably due to the healthcare-associated mucormycosis (HCM) in a diabetic patient. Although cannot be proved with certainty, we surmise that intubation as a risk factor in our case. The diagnosis was confirmed by histopathological examination (HPE) of the necrotic tissue specimen. The patient was responded well to lipid complex amphotericin B (250mg) regime after surgery. Subsequent follow up revealed that no signs of recurrence. Early, recognition, diagnosis, prompt treatment and awareness among clinician are representing the most effective way of managing the disease.
Matched MeSH terms: Amphotericin B/administration & dosage; Amphotericin B/therapeutic use
We describe a 2 year-old non-immunocompromised girl with disseminated histoplasmosis who presented with a 2-month history of fever and bloody diarrhoea. On presentation, she was severely wasted and anaemic. There were gross hepatosplenomegaly and multiple lymphadenopathy. A septic screen was negative. A subsequent stool culture isolated Salmonella enteriditis. Serial Widal-Weil Felix (WWF) titres showed serological response after 2 weeks of Ceftriaxone. However, she continued to have spiking fever, bloody diarrhoea and weight loss. She developed pancytopaenia and disseminated intravascular coagulation. A bone marrow aspirate and trephine, and lymph node biopsy showed the presence of Histoplasma capsulatum, confirmed by Gomori-Methenamine Silver staining. She responded to intravenous amphotericin B followed by fluconazole (intravenous then oral) for 6 months after discharge. Human Immunodeficiency Virus screening tests were negative. Complement and immunoglobulin levels were normal. T and B enumeration tests showed gross leucopaenia with very low T cell function with defective phagocytic function. A repeat T and B cell enumeration test and phagocytic function tests done 3 months later were normal.
Matched MeSH terms: Amphotericin B/therapeutic use
Kodamaea ohmeri keratitis is an opportunistic pathogen seen in patients who have undergone invasive procedures and immunocompromised state. It has been identified in septicemia patients, resulting in mortality. To the best of our knowledge, we identified the first case of K. ohmeri keratitis following an injury with vegetative material. A 57-year-old woman with underlying, poorly controlled diabetes mellitus was gardening when a tree leaf accidentally poked her in the eye. Two weeks later, the patient presented with right eye pain, redness and progressive blurring of vision due to a traumatised right cornea. Slit-lamp examination showed a small inferior paracentral corneal stromal infiltrate with overlying epithelial defect. A corneal scraping sample yielded K. ohmeri from Analytical Profile Index (API) 20C yeast identification system. She was treated with intensive topical amphotericin B and fluconazole. After 6 weeks of treatment, the keratitis resolved with faint scar tissue, and her visual acuity improved.
Matched MeSH terms: Amphotericin B/administration & dosage; Amphotericin B/therapeutic use
Aim. To report a case of refractory fungal keratitis caused by Scedosporium apiospermum. Methods. Interventional case report. Results. A 47-year-old Malay housewife presented with left eye cornea ulcer as her first presentation of diabetes mellitus. There was no history of ocular trauma, contact lens used, or cornea foreign body. Scedosporium apiospermum was isolated from the cornea scrapping. Her cornea ulcer initially responded well to topical Amphotericin B within 3 days but subsequently worsened. Repeat cornea scrapping also yields Scedosporium apiospermum. This refractory keratitis was successfully treated with a combination of topical Amphotericin B and Voriconazole over 6 weeks. Conclusion. Scedosporium apiospermum keratitis is an opportunistic infection, which is difficult to treat despite tight control of diabetes mellitus and intensive antifungal treatment. The infection appeared to have very quick onset but needed long duration of treatment to completely heal. Surgical debridement always plays an important role as a therapeutic procedure as well as establishes the diagnosis through repeat scrapping.
Rhinocerebral mucormycosis is an invasive fungal sinusitis with a high mortality rate, especially in immunocompromised patients. A 70-year-old woman, with uncontrolled type 2 diabetes mellitus, presented with a one-month history of non-specific headaches associated with progressive swelling of her left eye. Computed tomography of the brain and orbits showed the extensive involvement of bilateral intranasal sinuses, orbits, extraocular muscle and soft tissues. The diagnosis of invasive mucormycosis was confirmed from a tissue biopsy taken from the internasal septum. Despite the extensive mucormycosis invasion, she was successfully treated with intranasal and systemic amphotericin B and minimal adjunctive intranasal sphenoidotomy.
Matched MeSH terms: Amphotericin B/therapeutic use