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1.
Article in English | MEDLINE | ID: mdl-29866870

ABSTRACT

Central-line-associated bloodstream infections are increasingly recognized to be associated with intraluminal microbial biofilms, and effective measures for the prevention and treatment of bloodstream infections remain lacking. This report evaluates a new commercially developed antimicrobial catheter lock solution (ACL), containing trimethoprim (5 mg/ml), ethanol (25%), and calcium EDTA (Ca-EDTA) (3%), for activity against bacterial and fungal biofilms, using in vitro and in vivo (rabbit) catheter biofilm models. Biofilms were formed by bacterial (seven different species, including vancomycin-resistant Enterococcus [VRE]) or fungal (Candida albicans) species on catheter materials. Biofilm formation was evaluated by quantitative culture (CFU) and scanning electron microscopy (SEM). Treatment with ACL inhibited the growth of adhesion-phase biofilms in vitro after 60 min (VRE) or 15 min (all others), while mature biofilms were completely inhibited after exposure for 2 or 4 h, compared to control. Similar results were observed for drug-resistant bacteria. Compared to the heparinized saline controls, ACL lock therapy significantly reduced the catheter bacterial (3.49 ± 0.75 versus 0.03 ± 0.06 log CFU/catheter; P = 0.016) and fungal (2.48 ± 1.60 versus 0.55 ± 1.19 log CFU/catheter segment; P = 0.013) burdens in the catheterized rabbit model. SEM also demonstrated eradication of bacterial and fungal biofilms in vivo on catheters exposed to ACL, while vigorous biofilms were observed on untreated control catheters. Our results demonstrated that ACL was efficacious against both adhesion-phase and mature biofilms formed by bacteria and fungi in vitro and in vivo.


Subject(s)
Antifungal Agents/pharmacology , Bacteria/drug effects , Biofilms/drug effects , Anti-Bacterial Agents/pharmacology , Candida albicans/drug effects , Enterococcus/drug effects , Microscopy, Electron, Scanning
2.
mBio ; 7(5)2016 09 20.
Article in English | MEDLINE | ID: mdl-27651359

ABSTRACT

UNLABELLED: Crohn's disease (CD) results from a complex interplay between host genetic factors and endogenous microbial communities. In the current study, we used Ion Torrent sequencing to characterize the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in patients with CD and their nondiseased first-degree relatives (NCDR) in 9 familial clusters living in northern France-Belgium and in healthy individuals from 4 families living in the same area (non-CD unrelated [NCDU]). Principal component, diversity, and abundance analyses were conducted, and CD-associated inter- and intrakingdom microbial correlations were determined. Significant microbial interactions were identified and validated using single- and mixed-species biofilms. CD and NCDR groups clustered together in the mycobiome but not in the bacteriome. Microbiotas of familial (CD and NCDR) samples were distinct from those of nonfamilial (NCDU) samples. The abundance of Serratia marcescens and Escherichia coli was elevated in CD patients, while that of beneficial bacteria was decreased. The abundance of the fungus Candida tropicalis was significantly higher in CD than in NCDR (P = 0.003) samples and positively correlated with levels of anti-Saccharomyces cerevisiae antibodies (ASCA). The abundance of C. tropicalis was positively correlated with S. marcescens and E. coli, suggesting that these organisms interact in the gut. The mass and thickness of triple-species (C. tropicalis plus S. marcescens plus E. coli) biofilm were significantly greater than those of single- and double-species biofilms. C. tropicalis biofilms comprised blastospores, while double- and triple-species biofilms were enriched in hyphae. S. marcescens used fimbriae to coaggregate or attach with C. tropicalis/E. coli, while E. coli was closely apposed with C. tropicalis Specific interkingdom microbial interactions may be key determinants in CD. IMPORTANCE: Here, we characterized the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in multiplex families with CD and healthy relatives and defined the microbial interactions leading to dysbiosis in CD. We identified fungal (Candida tropicalis) and bacterial (Serratia marcescens and Escherichia coli) species that are associated with CD dysbiosis. Additionally, we found that the level of anti-Saccharomyces cerevisiae antibodies (ASCA; a known CD biomarker) was associated with the abundance of C. tropicalis We also identified positive interkingdom correlations between C. tropicalis, E. coli, and S. marcescens in CD patients and validated these correlations using in vitro biofilms. These results provide insight into the roles of bacteria and fungi in CD and may lead to the development of novel treatment approaches and diagnostic assays.


Subject(s)
Crohn Disease/microbiology , Dysbiosis/microbiology , Gastrointestinal Microbiome , Microbial Interactions , Mycobiome , Adult , Biofilms/growth & development , Candida tropicalis/isolation & purification , Crohn Disease/genetics , Escherichia coli/isolation & purification , Feces/microbiology , Female , Fimbriae, Bacterial , France , Healthy Volunteers , Humans , Hyphae/isolation & purification , Male , Middle Aged , Saccharomyces cerevisiae/immunology , Serratia marcescens/isolation & purification
4.
Cell Death Differ ; 22(8): 1363-77, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25633199

ABSTRACT

Neuroprotectin D1 (NPD1), a docosahexaenoic acid (DHA)-derived mediator, induces cell survival in uncompensated oxidative stress (OS), neurodegenerations or ischemic stroke. The molecular principles underlying this protection remain unresolved. We report here that, in retinal pigment epithelial cells, NPD1 induces nuclear translocation and cREL synthesis that, in turn, mediates BIRC3 transcription. NPD1 activates NF-κB by an alternate route to canonical signaling, so the opposing effects of TNFR1 and NPD1 on BIRC3 expression are not due to interaction/s between NF-κB pathways. RelB expression follows a similar pattern as BIRC3, indicating that NPD1 also is required to activate cREL-mediated RelB expression. These results suggest that cREL, which follows a periodic pattern augmented by the lipid mediator, regulates a cluster of NPD1-dependent genes after cREL nuclear translocation. BIRC3 silencing prevents NPD1 induction of survival against OS. Moreover, brain NPD1 biosynthesis and selective neuronal BIRC3 abundance are increased by DHA after experimental ischemic stroke followed by remarkable neurological recovery. Thus, NPD1 bioactivity governs key counter-regulatory gene transcription decisive for retinal and brain neural cell integrity when confronted with potential disruptions of homeostasis.


Subject(s)
Docosahexaenoic Acids/pharmacology , Inhibitor of Apoptosis Proteins/metabolism , Proto-Oncogene Proteins c-rel/metabolism , Ubiquitin-Protein Ligases/metabolism , Baculoviral IAP Repeat-Containing 3 Protein , Cell Survival/drug effects , Cell Survival/genetics , Cells, Cultured , Humans , Inhibitor of Apoptosis Proteins/genetics , Oxidative Stress/drug effects , Oxidative Stress/genetics , Signal Transduction/drug effects , Transcription Factor RelB/genetics , Transcription Factor RelB/metabolism , Ubiquitin-Protein Ligases/genetics
5.
Cell Mol Neurobiol ; 35(2): 197-204, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25212825

ABSTRACT

Docosahexaenoic acid (DHA), an omega-3 fatty acid family member, is obtained by diet or synthesized from dietary essential omega-3 linolenic acid and delivered systemically to the choriocapillaris, from where it is taken up by the retinal pigment epithelium (RPE). DHA is then transported to the inner segments of photoreceptors, where it is incorporated in phospholipids during the biogenesis of outer segment disk and plasma membranes. As apical photoreceptor disks are gradually shed and phagocytized by the RPE, DHA is retrieved and recycled back to photoreceptor inner segments for reassembly into new disks. Under uncompensated oxidative stress, the docosanoid neuroprotectin D1 (NPD1), a potent mediator derived from DHA, is formed by the RPE and displays its bioactivity in an autocrine and paracrine fashion. The purpose of this study was to determine whether photoreceptors have the ability to synthesize NPD1, and whether or not this lipid mediator exerts bioactivity on these cells. For this purpose, 661W cells (mouse-derived photoreceptor cells) were used. First we asked whether these cells have the ability to form NPD1 by incubating cells with deuterium (d4)-labeled DHA exposed to dark and bright light treatments, followed by LC-MS/MS-based lipidomic analysis to identify and quantify d4-NPD1. The second question pertains to the potential bioactivity of these lipids. Therefore, cells were incubated with 9-cis-retinal in the presence of bright light that triggers cell damage and death. Following 9-cis-retinal loading, DHA, NPD1, or vehicle were added to the media and the 661W cells maintained either in darkness or under bright light. DHA and NPD1 were then quantified in cells and media. Regardless of lighting conditions, 661W cells acquired DHA from the media and synthesized 4-9 times as much d4-NPD1 under bright light treatment in the absence and presence of 9-cis-retinal compared to cells in darkness. Viability assays of 9-cis-retinal-treated cells demonstrated that 34 % of the cells survived without DHA or NPD1. However, after bright light exposure, DHA protected 23 % above control levels and NPD1 increased protection by 32 %. In conclusion, the photoreceptor cell line 661W has the capability to synthesize NPD1 from DHA when under stress, and, in turn, can be protected from stress-induced apoptosis by DHA or NPD1, indicating that photoreceptors effectively contribute to endogenous protective signaling mediated by NPD1 under stressful conditions.


Subject(s)
Cytoprotection/radiation effects , Docosahexaenoic Acids/biosynthesis , Docosahexaenoic Acids/pharmacology , Light , Oxidative Stress/radiation effects , Retinal Cone Photoreceptor Cells/metabolism , Animals , Cell Line , Cytoprotection/drug effects , Diterpenes , Mice , Oxidative Stress/drug effects , Retinaldehyde
6.
Indian J Med Ethics ; 11(4): 237-41, 2014.
Article in English | MEDLINE | ID: mdl-25377037

ABSTRACT

The study assessed 54 advertisements of 145 different drugs, published over one year (from December 2011 to November 2012) in an Indian medical journal, circulated widely mainly among general practitioners (GPs). The ethical guidelines of the World Health Organization (WHO) and Organisation of Pharmaceutical Producers of India (OPPI) for medicinal drug promotion were applied. The brand name was mentioned in all advertisements (100% compliance both with the WHO and OPPI criteria) and the names of the active ingredients were also mentioned in 128 (90.14%) advertisements. However, major adverse drug reactions were mentioned in only two advertisements (1.37%); precautions, contraindications and warnings in only two (1.37%); and major interactions in only one (0.68%). Only three advertisements (2.06%) were well substantiated with references. To ensure the ethical promotionof drugs among GPs, journals must introduce compulsory review and appraisal of promotional advertisements by a dedicated review board, including at least one member trained in pharmacology and one representative from the medical division of a pharmaceutical company.


Subject(s)
Advertising/ethics , Drug Industry/ethics , Ethics, Business , Periodicals as Topic/ethics , Pharmaceutical Preparations , Ethical Review , General Practice , Guideline Adherence , Humans , India , Publishing
7.
Int J Tuberc Lung Dis ; 18(6): 682-8, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24903939

ABSTRACT

OBJECTIVE: To evaluate the association between oral candidiasis and tuberculosis (TB) in human immunodeficiency virus (HIV) infected individuals in sub-Saharan Africa, and to investigate oral candidiasis as a potential tool for TB case finding. METHODS: Protocol A5253 was a cross-sectional study designed to improve the diagnosis of pulmonary TB in HIV-infected adults in high TB prevalence countries. Participants received an oral examination to detect oral candidiasis. We estimated the association between TB disease and oral candidiasis using logistic regression, and sensitivity, specificity and predictive values. RESULTS: Of 454 participants with TB culture results enrolled in African sites, the median age was 33 years, 71% were female and the median CD4 count was 257 cells/mm(3). Fifty-four (12%) had TB disease; the prevalence of oral candidiasis was significantly higher among TB cases (35%) than among non-TB cases (16%, P < 0.001). The odds of having TB was 2.4 times higher among those with oral candidiasis when controlling for CD4 count and antifungals (95%CI 1.2-4.7, P = 0.01). The sensitivity of oral candidiasis as a predictor of TB was 35% (95%CI 22-48) and the specificity 85% (95%CI 81-88). CONCLUSION: We found a strong association between oral candidiasis and TB disease, independent of CD4 count, suggesting that in resource-limited settings, oral candidiasis may provide clinical evidence for increased risk of TB and contribute to TB case finding.


Subject(s)
Candidiasis, Oral/epidemiology , Coinfection , HIV Infections/epidemiology , Tuberculosis, Pulmonary/epidemiology , Adolescent , Adult , Africa South of the Sahara/epidemiology , Aged , CD4 Lymphocyte Count , Candidiasis, Oral/diagnosis , Candidiasis, Oral/immunology , Candidiasis, Oral/microbiology , Chi-Square Distribution , Cross-Sectional Studies , Female , HIV Infections/diagnosis , HIV Infections/immunology , HIV Infections/virology , Humans , Logistic Models , Male , Middle Aged , Odds Ratio , Predictive Value of Tests , Prevalence , Risk Assessment , Risk Factors , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/immunology , Tuberculosis, Pulmonary/microbiology , Young Adult
8.
Langmuir ; 30(15): 4465-73, 2014 Apr 22.
Article in English | MEDLINE | ID: mdl-24678973

ABSTRACT

In this work, we demonstrate two important features that arise out of introducing a liquid-crystalline (LC) compound into the rotator phase matrix and the consequent competition between the anisometric segments of the LC moieties and the aliphatic units. First, we show that the change in the structural character of the mixed medium depends on which of the entities forms the minority concentration: in the case of this being the alkane, the two components of the binary system are nanophase segregated, whereas if the LC molecules are present in a small concentration, then the layered structure merely gets roughened without any segregation. The second and more significant result of the calorimetric and X-ray experiments, at low LC concentrations, is the induction of a rotator phase that leads to unusual phase sequence not reported hitherto. Possible scenarios for the molecular arrangement are discussed. A Landau model is also presented that explains some of the observed features.

9.
3 Biotech ; 4(3): 275-281, 2014 Jun.
Article in English | MEDLINE | ID: mdl-28324430

ABSTRACT

We have isolated three novel strains of Trichoderma (two T. harzianum and one T. atroviride) from wild mushroom and tree bark, and evaluated their biocontrol potential against Sclerotium delphinii infecting cultivated cotton seedlings. T. harzianum strain CICR-G, isolated as a natural mycoparasite on a tree-pathogenic Ganoderma sp. exhibited the highest disease suppression ability. This isolate was formulated into a talcum-based product and evaluated against the pathogen in non-sterile soil. This isolate conidiated profusely under conditions that are non-conducive for conidiation by three other Trichoderma species tested, thus having an added advantage from commercial perspective.

10.
Indian J Lepr ; 85(2): 59-64, 2013.
Article in English | MEDLINE | ID: mdl-24236364

ABSTRACT

Secular trends in incidence of leprosy serve as a powerful tool in determining progress in reaching eradication. However, the interpretation of these trends must take into account both operational and epidemiological factors. A study was done to assess a time trend in the ratios of MB & PB from 2001 to 2010 based on the leprosy patients registered in a referral hospital in UP, India. Data were analyzed based on the gender, age and residence. Regardless of these factors, MB proportion shows no significant trends. These findings are discussed and it is concluded that we are no more close to eradication as compared to the status over a decade ago. Hence, much greater efforts will be required to promote early detections of MB cases, whether children or adults, male or female.


Subject(s)
Leprosy, Multibacillary/epidemiology , Leprosy, Paucibacillary/epidemiology , Adult , Child , Female , Humans , India/epidemiology , Male , Retrospective Studies , Tertiary Care Centers/statistics & numerical data
11.
Phys Rev Lett ; 111(24): 243201, 2013 Dec 13.
Article in English | MEDLINE | ID: mdl-24483657

ABSTRACT

We present an experimental determination of the 2p3d(1Po)→1s3d(1De) x-ray line emitted from He-like Si, S, and Cl projectile ions, excited in collisions with thin carbon foils, using a high-resolution bent-crystal spectrometer. A good agreement between the observation and state-of-the-art relativistic calculations using the multiconfiguration Dirac-Fock formalism including the Breit interaction and QED effects implies the dominance of fluorescent decay over the autoionization process for the 2p3d(^{1}P^{o}) state of He-like heavy ions. This is the first observation of the fluorescence-active doubly excited states in He-like Si, S, and Cl ions.

12.
Eur Phys J E Soft Matter ; 35(4): 9705, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22526979

ABSTRACT

Using the Landau model, the temperature and frequency dependence of the complex non-linear dielectric effect in the isotropic phase above the isotropic-smectic-A phase transition is calculated. Comparing the results of the calculations with existing data, we finally conclude that the model provides a description of the isotropic-smectic-A transition that takes all experimentally known features of the non-linear dielectric effect in the isotropic phase into account in a qualitatively correct way.


Subject(s)
Liquid Crystals/chemistry , Models, Chemical , Phase Transition , Anisotropy , Computer Simulation , Electric Conductivity , Temperature
13.
Asian Pac J Trop Biomed ; 2(10): 782-6, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23569847

ABSTRACT

OBJECTIVE: To conduct a systemic evaluation of the medicinal value of seeds which include macroscopic and microscopic characterization, physiochemical evaluation, preliminary phytochemical screening and experimental antipyretic activity. METHODS: Saraca asoca seed was studied for pharmacognostical, phytochemical and other recommended methods for standardizations. Also, the acetone extract of the seeds was evaluated for acute toxicity study and antipyretic activity using Brewer's yeast induced pyrexia in Wistar rats at oral doses of 300 mg/kg and 500 mg/kg. RESULTS: After phytochemical screening, the acetone extract showed the presence of saponin, tannins and flavonoids which inhibit pyrexia. The therapeutic efficacy achieved at both the dose levels of the research drug and standard drug aspirin (100 mg/kg) showed significant (P<0.01) antipyretic activity when compared to the control group. The highly significant antipyretic effect exhibited at the dose of 500 mg/kg was also found to be sustainable in nature. CONCLUSIONS: The antipyretic effect of the acetone extract showed significant results in rats at the dose of 500 mg/kg after following the standard pharmacognostical and phytochemical methods.


Subject(s)
Antipyretics/chemistry , Antipyretics/pharmacology , Fabaceae/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Seeds/chemistry , Animals , Female , Male , Mice , Phytochemicals/chemistry , Rats , Seeds/cytology , Toxicity Tests, Acute
14.
Mini Rev Med Chem ; 11(3): 247-62, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21222577

ABSTRACT

Acetylcholinesterase (AChE) inhibitors are considered as promising therapeutic agents for the treatment of several neurological disorders such as Alzheimer's disease (AD), senile dementia, ataxia and myasthenia gravis. There are only few synthetic medicines with adverse effects, available for treatment of cognitive dysfunction and memory loss associated with these diseases. A variety of plants has been reported to possess AChE inhibitory activity and so may be relevant to the treatment of neurodegenerative disorders such as AD. Hence, developing potential AChE inhibitors from botanicals is the need of the day. This review will cover some of the promising acetylcholinesterase inhibitors isolated from plants with proven in vitro and in vivo activities with concern to their structure activity relationship.


Subject(s)
Acetylcholinesterase/chemistry , Cholinesterase Inhibitors/chemistry , Acetylcholinesterase/metabolism , Alkaloids/chemistry , Alkaloids/pharmacology , Alkaloids/therapeutic use , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/therapeutic use , Glycosides/chemistry , Glycosides/pharmacology , Glycosides/therapeutic use , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/pharmacology , Heterocyclic Compounds/therapeutic use , Humans , Nervous System Diseases/drug therapy , Sterols/chemistry , Sterols/pharmacology , Sterols/therapeutic use , Stilbenes/chemistry , Stilbenes/pharmacology , Stilbenes/therapeutic use , Structure-Activity Relationship , Terpenes/chemistry , Terpenes/pharmacology , Terpenes/therapeutic use
15.
Eur J Clin Microbiol Infect Dis ; 30(5): 629-33, 2011 May.
Article in English | MEDLINE | ID: mdl-21210170

ABSTRACT

Gentian violet (GV) is recommended for initial treatment of oral candidiasis in HIV-infected patients in resource-limited settings. Currently GV is not used because of its staining effects. In this study, we investigated the staining capacity of three different concentrations of GV to determine a concentration that does not cause staining. The selected concentration that did not cause staining was evaluated for its physical stability and antifungal activity. Fifteen healthy participants were randomized to rinse twice daily for 14 days with one of three GV concentrations: 0.1%, 0.0085%, or 0.00165%. Oral examination and intra-oral photographs were performed at baseline and at the end of therapy. Participants responded to a questionnaire to assess adverse events. Antifungal activity was evaluated using the Clinical and Laboratory Standard Institute methodology. GV at a concentration of 0.00165% did not stain the oral mucosa and was well tolerated. GV at a concentration of 0.00165% was stable and possessed antifungal activity when stored at certain temperatures for different time periods. Gentian violet solution at the concentration of 0.00165% does not stain the oral mucosa, is stable and possesses potent antifungal activity.


Subject(s)
Antifungal Agents/administration & dosage , Antifungal Agents/adverse effects , Candida/drug effects , Candidiasis, Oral/drug therapy , Gentian Violet/administration & dosage , Gentian Violet/adverse effects , Adolescent , Adult , HIV Infections/complications , Human Experimentation , Humans , Mouth Mucosa/drug effects , Mouth Mucosa/pathology , Surveys and Questionnaires , Treatment Outcome , Young Adult
16.
J Chemother ; 23(6): 319-25, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22233814

ABSTRACT

The discovery of echinocandins, and their development and approval, was hailed as a significant addition to our antifungal armamentarium, previously predominated by polyenes and azoles. To date, three echinocandins (anidulafungin, caspofungin, and micafungin) have been approved by the U.S. Food and Drug Administration for the treatment of fungal infections. Since all three echinocandins target the fungal cell wall and share a similar structural chemical backbone, they are perceived to be identical. However, a scientific literature review shows distinct differences among the echinocandins in terms of in vitro activity, fungicidal activity, post-antifungal effect, paradoxical effect, and activity on biofilms. More investigation is warranted to determine if the observed differences among the echinocandins can translate to clinical advantages.


Subject(s)
Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Echinocandins/chemistry , Echinocandins/pharmacology , Mycoses/drug therapy , Animals , Humans
17.
Eur Phys J E Soft Matter ; 33(3): 175-81, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20936322

ABSTRACT

A new Landau-type phenomenological free-energy function to describe the nematic-smectic-A transition, smectic-A-smectic-C transition and nematic-smectic-C transition is proposed. The influence of pressure on the these phase transitions is discussed by varying the coupling between various order parameters. The phase diagram of the thermodynamic parameters is studied and a possible nematic-smectic-A-smectic-C bicritical point is predicted. We present a detailed analysis of the different phases that can occur and analyze the question under which conditions a bicritical point is observed in the phase diagram. The obtained topology of the pressure-temperature phase diagram is consistent with experimental results.


Subject(s)
Liquid Crystals/chemistry , Models, Chemical , Nanoparticles/chemistry , Phase Transition , Pressure , Temperature
18.
J Clin Microbiol ; 48(10): 3750-2, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20668120

ABSTRACT

Currently, no agar-based susceptibility testing method has been standardized for testing dermatophytes. We describe a newly developed agar-based method employing disk diffusion assay to test the susceptibility of 47 isolates of dermatophytes against 8 antifungals. Our results show that the method is reproducible, is simple, and could be used to determine the antifungal susceptibility of dermatophytes.


Subject(s)
Antifungal Agents/pharmacology , Arthrodermataceae/drug effects , Agar , Antifungal Agents/chemistry , Arthrodermataceae/isolation & purification , Culture Media/chemistry , Diffusion , Humans , Microbial Sensitivity Tests/methods , Reproducibility of Results
19.
Clin Microbiol Infect ; 15(3): 274-9, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19210699

ABSTRACT

Recent studies suggest that differences in antifungal activity among echinocandins may exist. In this study, the activities of three echinocandins (anidulafungin, caspofungin, and micafungin) against Candida parapsilosis isolates from burn unit patients, healthcare workers and the hospital environment were determined. Additionally, the effect of these echinocandins on the cell morphology of caspofungin-susceptible and caspofungin-non-susceptible isolates was assessed using scanning electron microscopy (SEM). The C. parapsilosis isolates obtained from patients were susceptible to anidulafungin, but were less so to caspofungin and micafungin. Isolates obtained from healthcare workers or environmental sources were susceptible to all antifungals. SEM data demonstrated that although anidulafungin and caspofungin were equally active against a caspofungin-susceptible C. parapsilosis strain, they differed in their ability to damage a caspofungin-non-susceptible strain, for which lower concentrations of anidulafungin (1 mg/L) than of caspofungin (16 mg/L) were needed to induce cellular damage and distortion of the cellular morphology. To determine whether the difference in the antifungal susceptibility of C. parapsilosis isolates to anidulafungin as compared to the other two echinocandins could be due to different mutations in the FKS1 gene, the sequences of the 493-bp region of this gene associated with echinocandin resistance were compared. No differences in the corresponding amino acid sequences were observed, indicating that differences in activity between anidulafungin and the other echinocandins are not related to mutations in this region. The results of this study provide evidence that differences exist between the activities of anidulafungin and the other echinocandins.


Subject(s)
Antifungal Agents/pharmacology , Burns/microbiology , Candida/drug effects , Candida/isolation & purification , Echinocandins/pharmacology , Lipopeptides/pharmacology , Anidulafungin , Burn Units , Candida/ultrastructure , Candidiasis/microbiology , Carrier State/microbiology , Caspofungin , Environmental Microbiology , Fungal Proteins/genetics , Genotype , Glucosyltransferases/genetics , Health Personnel , Humans , Micafungin , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Sequence Analysis, DNA
20.
Nanotechnology ; 19(7): 075103, 2008 Feb 20.
Article in English | MEDLINE | ID: mdl-21817628

ABSTRACT

A controlled and up-scalable biosynthetic route to nanocrystalline silver particles with well-defined morphology using cell-free aqueous filtrate of a non-pathogenic and commercially viable biocontrol agent Trichoderma asperellum is being reported for the first time. A transparent solution of the cell-free filtrate of Trichoderma asperellum containing 1 mM AgNO(3) turns progressively dark brown within 5 d of incubation at 25 °C. The kinetics of the reaction was studied using UV-vis spectroscopy. An intense surface plasmon resonance band at ∼410 nm in the UV-vis spectrum clearly reveals the formation of silver nanoparticles. The size of the silver particles using TEM and XRD studies is found to be in the range 13-18 nm. These nanoparticles are found to be highly stable and even after prolonged storage for over 6 months they do not show significant aggregation. A plausible mechanism behind the formation of silver nanoparticles and their stabilization via capping has been investigated using FTIR and surface-enhanced resonance Raman spectroscopy.

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