<b>BACKGROUNDb>Candida albicans (C. albicans) can become a pathogen causing superficial as well as life-threatening systemic infections, especially in immunocompromised patients. Many phenotypic attributes contribute to its capacity to colonize human organs. In our study, 93 C. albicans isolates from patients of various candidiasis in a hospital of China were surveyed. We aimed to investigate the white-opaque (WO) switching competence, drug sensitivity, and virulence of mating type-like (MTL) a/α isolates.

<b>METHODSb>Internal transcribed spacer (ITS) gene and the MTL configuration were detected in all the isolates by reverse transcription-polymerase chain reaction. White/opaque phenotype and doubling time of cell growth were determined. The minimum inhibitory concentrations of antifungal agent were measured using broth microdilution method.

<b>RESULTSb>Sixty-four isolates (69.6%) were classified to serotype A, 19 (20.6%) to serotype B, and 9 (9.8%) to serotype C. Moreover, phylogenetic analysis showed that these isolates were divided into four different subgroups of ITS genotypes. Most of our clinical isolates were MTL a/α type, while 6.8% remained MTL a or MTLα type. The frequency of opaque phenotype was 71.0% (66 isolates). Following the guidelines of Clinical and Laboratory Standards Institute M27-A3, all isolates were susceptible to caspofungin and a few (0.6-3.2%) of them showed resistance against amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole.

<b>CONCLUSIONSb>From these analyses, there were comparatively more C. albicans strains classified into serotype B, and the frequency of opaque phase strains was significant in the clinical isolates from China. Genetic, phenotypic, or drug susceptibility patterns were not significantly different from previous studies. MTL a/α isolates could also undergo WO switching which facilitates their survival.

Amphotericin B ; pharmacology ; Antifungal Agents ; pharmacology ; Candida albicans ; classification ; drug effects ; genetics ; Fluconazole ; pharmacology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Phylogeny

Leishmaniasis is a worldwide uncontrolled parasitic disease due to the lack of effective drug and vaccine. To speed up effective drug development, we need powerful methods to rapidly assess drug effectiveness against the intracellular form of Leishmania in high throughput assays. Reporter gene technology has proven to be an excellent tool for drug screening in vitro. The effects of reporter proteins on parasite infectivity should be identified both in vitro and in vivo. In this research, we initially compared the infectivity rate of recombinant Leishmania major expressing stably enhanced green fluorescent protein (EGFP) alone or EGFP-luciferase (EGFP-LUC) with the wild-type strain. Next, we evaluated the sensitivity of these parasites to amphotericin B (AmB) as a standard drug in 2 parasitic phases, promastigote and amastigote. This comparison was made by MTT and nitric oxide (NO) assay and by quantifying the specific signals derived from reporter genes like EGFP intensity and luciferase activity. To study the amastigote form, both B10R and THP-1 macrophage cell lines were infected in the stationary phase and were exposed to AmB at different time points. Our results clearly revealed that the 3 parasite lines had similar in vitro infectivity rates with comparable parasite-induced levels of NO following interferon-gamma/lipopolysaccharide induction. Based on our results we proposed the more reporter gene, the faster and more sensitive evaluation of the drug efficiency.
Amphotericin B/*pharmacology ; Animals ; Antiprotozoal Agents/*pharmacology ; Drug Evaluation, Preclinical/instrumentation/*methods ; Female ; Gene Expression ; Genes, Reporter ; Green Fluorescent Proteins/genetics/*metabolism ; Humans ; Leishmania major/*drug effects/genetics/growth & development/physiology ; Leishmaniasis, Cutaneous/*parasitology ; Luciferases/genetics/*metabolism ; Mice

BACKGROUND: We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method. METHODS: A total of 136 Aspergillus isolates obtained from 11 university hospitals were identified by sequencing the internal transcribed spacer (ITS) and beta-tubulin genomic regions. Minimal inhibitory concentrations (MICs) of AMB were determined in Etests using Mueller-Hinton agar (Etest-MH) and RPMI agar (Etest-RPG), and categorical agreement with the CLSI method was assessed by using epidemiological cutoff values. RESULTS: ITS sequencing identified the following six Aspergillus species complexes: Aspergillus fumigatus (42.6% of the isolates), A. niger (23.5%), A. flavus (17.6%), A. terreus (11.0%), A. versicolor (4.4%), and A. ustus (0.7%). Cryptic species identifiable by beta-tubulin sequencing accounted for 25.7% (35/136) of the isolates. Of all 136 isolates, 36 (26.5%) had AMB MICs of > or =2 microg/mL by the CLSI method. The categorical agreement of Etest-RPG with the CLSI method was 98% for the A. fumigatus, A. niger, and A. versicolor complexes, 87% for the A. terreus complex, and 37.5% for the A. flavus complex. That of Etest-MH was < or =75% for the A. niger, A. flavus, A. terreus, and A. versicolor complexes but was higher for the A. fumigatus complex (98.3%). CONCLUSIONS: Aspergillus species other than A. fumigatus constitute about 60% of clinical Aspergillus isolates, and reduced AMB susceptibility is common among clinical isolates of Aspergillus in Korea. Molecular identification and AMB susceptibility testing by Etest-RPG may be useful for characterizing Aspergillus isolates of clinical relevance.
Amphotericin B/*pharmacology ; Antifungal Agents/*pharmacology ; Aspergillus/*drug effects/isolation & purification ; DNA, Fungal/chemistry/genetics/metabolism ; Hospitals ; Humans ; Microbial Sensitivity Tests ; Mycoses/diagnosis/microbiology ; Republic of Korea ; Sequence Analysis, DNA ; Tubulin/genetics

No abstract available.
Amphotericin B/therapeutic use ; Antifungal Agents/pharmacology/therapeutic use ; Cryptococcosis/*diagnosis/drug therapy/microbiology ; Cryptococcus/classification/drug effects/*isolation & purification ; DNA, Ribosomal/chemistry/metabolism ; Fluconazole/therapeutic use ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Peritoneal Dialysis, Continuous Ambulatory ; Peritonitis/*diagnosis/etiology ; Phylogeny ; Saccharomyces cerevisiae/drug effects/isolation & purification ; Sequence Homology, Nucleic Acid

<b>OBJECTIVEb>To investigate the effect of amphotericinB (AmB) on migration and invasion of esophageal carcinoma Eca109 cells exposed to hypoxia and explore the molecular mechanisms.

<b>METHODSb>Routinely cultured esophageal carcinoma Eca109 cells were treated with 0, 1.25, 2.5, or 5 µg/ml AmB in hypoxic condition (3% O2, 5% CO2, and 92% N2) for 24 h. The cell migration and invasion were assessed by cell scratch test and Transwell chamber assay, respectively. Real-time quantitative PCR and Western blotting were used to detect the mRNA and protein expressions of hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase-2 (MMP-2), and E-cadherin in the cells, respectively.

<b>RESULTSb>Compared with the control cells, the cells treated with different doses of AmB showed attenuated ability of migration and invasion (P<0.05). AmB treatment resulted in significantly lowered mRNA and protein expressions of MMP-2 (P<0.05) and increased expressions of E-cadherin (P<0.05); the protein expression of HIF-1α decreased significantly in cells after AmB treatment (P<0.05) but its mRNA levels showed no significant changes (P>0.05).

<b>CONCLUSIONb>AmB can suppress the migration and invasion of esophageal carcinoma Eca109 cells in hypoxic microenvironment possibly by regulating the expressions of HIF-1α, MMP-2 and E-cadherin.

Amphotericin B ; pharmacology ; Cadherins ; metabolism ; Cell Hypoxia ; Cell Line, Tumor ; drug effects ; Cell Movement ; drug effects ; Down-Regulation ; Esophageal Neoplasms ; metabolism ; pathology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; RNA, Messenger

<b>OBJECTIVEb>Established with amphotericin B perforated patch-clamp technique, to study the electrophysiological properties of calyx synapses.

<b>METHODSb>In the present experiments, we studied the application of perforated patch clamp technique on the calyx synapses of mice with Amphotericin B.

<b>RESULTSb>The use of Amphotericin B significantly slowed down the decay of channel currents and the optimum concentration was 400 microg/ml.

<b>CONCLUSIONb>The syudy developed a stable of perforated patch clamp whole cell recording technique, could be more effecitve, more real reaction neurons electrophysiological characteristics of the channel current. Our work might provide the basic information to future users studying the signal transmission and regulation of auditory system of rodents.

Amphotericin B ; pharmacology ; Animals ; Mice ; Neurons ; drug effects ; Patch-Clamp Techniques

Candidemia due to uncommon Candida spp. appears to be increasing in incidence. C. dubliniensis has been increasingly recovered from individuals not infected with HIV. Identification of C. dubliniensis can be problematic in routine clinical practice due to its phenotypic resemblance to C. albicans. We report the first case of C. dubliniensis candidemia in Korea, which occurred in a 64-yr-old woman who presented with partial seizure, drowsiness, and recurrent fever. Germ-tube positive yeast that was isolated from blood and central venous catheter tip cultures formed smooth, white colonies on sheep blood agar and Sabouraud agar plates, indicative of Candida spp. C. dubliniensis was identified using the Vitek 2 system (bioMerieux, USA), latex agglutination, chromogenic agar, and multiplex PCR. The blood isolate was susceptible to flucytosine, fluconazole, voriconazole, and amphotericin B. After removal of the central venous catheter and initiation of fluconazole treatment, the patient's condition gradually improved, and she was cleared for discharge from our hospital. Both clinicians and microbiologists should be aware of predisposing factors to C. dubliniensis candidemia in order to promote early diagnosis and appropriate treatment.
Amphotericin B/pharmacology ; Antifungal Agents/pharmacology/therapeutic use ; Candida/drug effects/*isolation & purification ; Candidemia/*diagnosis/drug therapy ; Catheterization, Central Venous ; Female ; Fluconazole/pharmacology/therapeutic use ; Flucytosine/pharmacology ; Humans ; Microbial Sensitivity Tests ; Middle Aged ; Pyrimidines/pharmacology ; Triazoles/pharmacology

<b>OBJECTIVEb>To establish a perforated patch-clamp technology with amphotericin B and beta-escin and to research the regulation of small conductance calcium-activated potassium channel SK2 currents by calcium ions.

<b>METHODSb>Single human atrial myocytes were enzymatically isolated from the right atrial appendage. Amphotericin B and / or beta-escin were used by perforated electrode liquid. The regulation of SK2 current by calcium ions in human atrial myocytes was performed with the perforated patch-clamp technique. The intracellular calcium changes were measured by the intracellular calcium test system.

<b>RESULTSb>Mixed perforated electrode liquid compared with 150 microg/ml amphotericin B or 6.88 microg/ml beta-escin alone, it was easy to seal cells and activate SK2 current by the former method. Moreover, the ration of F340/380 was consistent with the change of intracellular free calcium ion concentration increase after the formation of perforation. The ration of F340/380 was measured by intracellular calcium test system.

<b>CONCLUSIONb>The appropriate concentration of amphotericin B mixed with beta-escin can form a stable whole-cell patch recording technology that is appropriate for the research of SK2 current regulation by intracellular calcium.

Amphotericin B ; pharmacology ; Calcium ; metabolism ; Electric Conductivity ; Escin ; pharmacology ; Humans ; Myocytes, Cardiac ; physiology ; Patch-Clamp Techniques ; Potassium Channels, Calcium-Activated ; drug effects

Candidaemia associated with intravascular catheter-associated infections is of great concern due to the resulting high morbidity and mortality. The antibiotic lock technique (ALT) was previously introduced to treat catheter-associated bacterial infections without removal of catheter. So far, the efficacy of ALT against Candida infections has not been rigorously evaluated. We investigated in vitro activity of ALT against Candida biofilms formed by C. albicans, C. glabrata, and C. tropicalis using five antifungal agents (caspofungin, amphotericin B, itraconazole, fluconazole, and voriconazole). The effectiveness of antifungal treatment was assayed by monitoring viable cell counts after exposure to 1 mg/mL solutions of each antibiotic. Fluconazole, itraconazole, and voriconazole eliminated detectable viability in the biofilms of all Candida species within 7, 10, and 14 days, respectively, while caspofungin and amphotericin B did not completely kill fungi in C. albicans and C. glabrata biofilms within 14 days. For C. tropicalis biofilm, caspofungin lock achieved eradication more rapidly than amphotericin B and three azoles. Our study suggests that azoles may be useful ALT agents in the treatment of catheter-related candidemia.
Amphotericin B/administration & dosage/pharmacology ; Antifungal Agents/*administration & dosage/pharmacology/therapeutic use ; Biofilms/*drug effects ; Candida albicans/*drug effects/physiology ; Candida glabrata/*drug effects/physiology ; Candida tropicalis/*drug effects/physiology ; Candidiasis/drug therapy ; Catheter-Related Infections/drug therapy ; Catheterization, Central Venous ; Drug Administration Routes ; Echinocandins/administration & dosage/pharmacology ; Fluconazole/administration & dosage/pharmacology ; Humans ; Itraconazole/administration & dosage/pharmacology ; Microbial Sensitivity Tests ; Pyrimidines/administration & dosage/pharmacology ; Triazoles/administration & dosage/pharmacology

<b>BACKGROUNDb>During recent years, the incidence of serious infections caused by opportunistic fungi has increased dramatically due to alterations of the immune status of patients with hematological diseases, malignant tumors, transplantations and so forth. Unfortunately, the wide use of triazole antifungal agents to treat these infections has lead to the emergence of Aspergillus spp. resistant to triazoles. The present study was to assess the in vitro activities of five antifungal agents (voriconazole, itraconazole, posaconazole, amphotericin B and caspofungin) against different kinds of Aspergillus spp. that are commonly encountered in the clinical setting.

<b>METHODSb>The agar-based Etest MIC method was employed. One hundred and seven strains of Aspergillus spp. (5 species) were collected and prepared according to Etest Technique Manuel. Etest MICs were determined with RPMI agar containing 2% glucose and were read after incubation for 48 hours at 35°C. MIC(50), MIC(90) and MIC range were acquired by Whonet 5.4 software.

<b>RESULTSb>The MIC(90) of caspofungin against A. fumigatus, A. flavus and A. nidulans was 0.094 µg/ml whereas the MIC(90) against A. niger was 0.19 µg/ml. For these four species, the MIC(90) of caspofungin was the lowest among the five antifungal agents. For A. terrus, the MIC(90) of posaconazole was the lowest. For A. fumigatus and A. flavus, the MIC(90) in order of increasing was caspofungin, posaconazole, voriconazole, itraconazole, and amphotericin B. The MIC of amphotericin B against A. terrus was higher than 32 µg/ml in all 7 strains tested.

<b>CONCLUSIONSb>The in vitro antifungal susceptibility test shows the new drug caspofungin, which is a kind of echinocandins, has good activity against the five species of Aspergillus spp. and all the triazoles tested have better in vitro activity than traditional amphotericin B.

Amphotericin B ; pharmacology ; Antifungal Agents ; pharmacology ; Aspergillus ; drug effects ; Echinocandins ; pharmacology ; Itraconazole ; pharmacology ; Lipopeptides ; Microbial Sensitivity Tests ; Pyrimidines ; pharmacology ; Triazoles ; pharmacology ; Voriconazole