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PubMed2005

In vitro testing of fungicidal activity of biocides against Aspergillus fumigatus.

The activity of biocides against Aspergillus fumigatus is unknown. In the European guidelines to evaluate the fungicidal activity of a biocide, the critical step concerning the preparation of conidial suspensions is cumbersome and time-consuming. The aims of this study were to evaluate a simplified procedure to prepare conidial suspensions to test a biocide in comparison with the recommended one and to investigate the in vitro activity of seven biocides by the suspension neutralization method against A. fumigatus clinical isolates. The proposed simplified procedure proved reproducible, gave the same results and was quicker than that described in the European guidelines. Benzalkonium chloride (0.25 %), glutaraldehyde (1.6 %), polyvinylpyrrolidone iodine (1 % available iodine) and polyester glycol iodine (0.18 % available iodine) showed biocidal activity in <or=5 min contact time, and chlorine (0.14 % available Cl) and chlorhexidine (0.06 %) after 15 min and 30-60 min, respectively. In contrast, chloramine-T (0.01 %) did not show biocidal activity. In addition, a simplified and reproducible procedure may be used for testing the fungicidal activity of new compounds or combined formulations. In conclusion, the biocides tested, which are commonly used in hospital settings, were shown to display biocidal activity against A. fumigatus and a simplified procedure may be adopted for testing the fungicidal activity of new compounds.

Anti-Infective Agents, Local↗
PubMed2000

NK cells eliminate Cryptococcus neoformans by potentiating the fungicidal activity of macrophages rather than by directly killing them upon stimulation with IL-12 and IL-18.

In the present study, we examined whether natural killer (NK) cells have direct fungicidal activity against Cryptococcus neoformans. Splenic NK cells were obtained from SCID mice and stimulated with a combination of interleukin (IL)-12 and IL-18 in flat culture plates or round tubes. They were then or at the same time cultured with the yeast cells and the number of viable yeast cells was examined. We could not detect direct fungicidal activity by NK cells under any culture condition, although they produced a large amount of IFN-gamma and exerted marked cytotoxic activity against YAC-1 cells. On the other hand, NK cells significantly potentiated the nitric oxide-mediated cryptococcocidal activity of thioglycolate-elicited peritoneal macrophages obtained from SCID mice upon stimulation with IL-12 and IL-18. The culture supernatants of NK cells stimulated with IL-12 and IL-18 provided similar results when used in place of NK cells. The induction of macrophage anticryptococcal activity by NK cells and NK cell culture supernatants were both mediated by IFN-gamma because the specific mAb almost completely abrogated such effect. Considered collectively, our results suggested that NK cells may play a regulatory role in potentiating macrophage-mediated fungicidal mechanisms in host resistance to infection with C. neoformans rather than exerting a direct killing activity against the fungal pathogen.

Animals↗
PubMed1990

Rilopirox--a new hydroxypyridone antifungal with fungicidal properties.

Rilopirox, 6-[[p-chlorophenoxy)phenoxy]methyl]-1hydroxy-4-methyl-2(1H)-pyrido ne, is a new fungicidal antimycotic with very low water solubility. It was designed to meet the demand for an intravaginal antifungal with a long skin retention time and a strong killing effect on pathogenic yeasts. In addition, it inhibits all common fungal pathogens in the range 0.98 to 15.6 micrograms/ml. Fungicidal rates vis-à-vis Trichophyton mentagrophytes and Candida albicans under proliferative and non-proliferative conditions are higher than those achieved with common azole and allylamine antifungals. Rilopirox is affected by Fe3+ ions and high concentrations of human serum owing to its chelating activity. The peptone source is of utmost importance to the inhibitory activity of rilopirox whereas the pH value seems to be unimportant so long as it is within the range 5-8.5. Rilopirox appears to meet the demand for an intravaginal antifungal as a result of its very low water solubility of 50 ng/ml and its immediate fungicidal action even under non-proliferative conditions.

Animals↗
PubMed1995

In vitro antifungal and fungicidal spectra of a new pradimicin derivative, BMS-181184.

A new pradimicin derivative, BMS-181184, was compared with amphotericin B and fluconazole against 249 strains from 35 fungal species to determine its antifungal spectrum. Antifungal testing was performed by the broth macrodilution reference method recommended by the National Committee for Clinical Laboratory Standards (document M27-P, 1992). BMS-181184 MICs for 97% of the 167 strains of Candida spp., Cryptococcus neoformans, Torulopsis glabrata, and Rhodotorula spp. tested were < or = 8 micrograms/ml, with a majority of MICs being 2 to 8 micrograms/ml. Similarly, for Aspergillus fumigatus and 89% of the 26 dermatophytes tested BMS-181184 MICs were < or = 8 micrograms/ml. BMS-181184 was fungicidal for the yeasts, dermatophytes, and most strains of A. fumigatus, although the reduction in cell counts was less for A. fumigatus than for the yeasts. BMS-181184 was active against Sporothrix schenckii, dematiaceous fungi, and some members of the non-Aspergillus hyaline hyphomycetes. BMS-181184, however, was not fungicidal against members of the family Dematiaceae. BMS-181184 lacked activity or had poorer activity (MICs, > or = 16 micrograms/ml) against Aspergillus niger, Aspergillus flavus, Malassezia furfur, Fusarium spp., Pseudallescheria boydii, Alternaria spp., Curvularia spp., Exserohilum mcginnisii, and the zygomycetes than against yeasts. The activity of BMS-181184 was minimally (twofold or less) affected by changes in testing conditions (pH, inoculum size, temperature, the presence of serum), testing methods (agar versus broth macrodilution), or test media (RPMI 1640, yeast morphology agar, high resolution test medium). Overall, our results indicate that BMS-181184 has a broad antifungal spectrum and that it is fungicidal to yeasts and, to a lesser extent, to filamentous fungi.

Amphotericin B↗
PubMed1996

Effect of fluconazole on fungicidal activity of flucytosine in murine cryptococcal meningitis.

Both animal and in vitro studies have demonstrated that combinations of flucytosine with amphotericin B and with fluconazole have significantly improved activity against cryptococcal meningitis compared with the activity of each drug used alone. However, very few dose levels of these agents have been tested in combination. This study evaluated the efficacy of fluconazole plus flucytosine in a murine model of cryptococcal meningitis over a broad range of dose combinations (fluconazole, 0 to 40 micrograms/g of body weight per day; flucytosine, 0 to 200 micrograms/g/day). Both drugs were dissolved in drinking water, with treatment on days 2 to 11. In this highly reproducible model, fluconazole had a dramatic effect on the fungicidal activity of flucytosine. Flucytosine at dose levels of as much as 200 micrograms/g/day alone or in combination with low doses of fluconazole had minimal fungicidal activity, whereas in combination with fluconazole at 24 to 40 micrograms/g/day, flucytosine showed fungicidal activity in the range of 45 to 65% of the animals treated at doses of 40 to 100 micrograms/g/day. This striking effect of fluconazole is consistent with the results of both in vitro and clinical studies. In the clinic, the use of flucytosine is often limited by severe toxicity, while toxicity is rarely observed with fluconazole. These results suggest that when flucytosine is given with higher doses of fluconazole, the maximum therapeutic effect of the former in the clinic may be observed at dose levels that are far less than the doses commonly employed (150 micrograms/g daily).

Animals↗
PubMed2003

Attenuation of itraconazole fungicidal activity following preexposure of Aspergillus fumigatus to fluconazole.

Fluconazole (FLC), a triazole with limited activity against Aspergillus species, is frequently used as prophylaxis in leukemia patients and bone marrow transplant recipients. Prior FLC use has been associated with an increasing incidence of invasive aspergillosis in these patients. We hypothesized that prior exposure of Aspergillus fumigatus to FLC could result in altered in vitro susceptibility of this fungus to other, more active triazoles. Thus, we performed serial passages of conidia of 10 clinical isolates of A. fumigatus (all itraconazole [ITC] susceptible) on FLC-containing yeast agar glucose plates. The MICs and minimal fungicidal concentrations (MFCs) of amphotericin B, FLC, ITC, and voriconazole (VRC) for A. fumigatus conidia were measured following four passages on FLC-containing medium according to the National Committee for Clinical Laboratory Standards microdilution method. Serial passages on FLC-containing plates resulted in a fourfold increase in the MFCs (but not the MICs) of ITC for nine isolates. The attenuated ITC fungicidal activity against A. fumigatus following FLC preexposure was medium independent and was also observed against FLC-preexposed A. fumigatus hyphae with the viability staining FUN-1 dye. Moreover, FLC preexposure of A. fumigatus conidia resulted in an analogous increase in the MFCs (but not the MICs) of VRC. Our findings suggest that preexposure of A. fumigatus to FLC attenuates the in vitro fungicidal activity of subsequent ITC use against it. This phenotypic adaptation is not captured by a routine MIC determination but requires MFC measurement. The in vivo significance of this in vitro phenomenon requires further investigation.

Antifungal Agents↗
PubMed2005

Caspofungin susceptibility testing of Candida inconspicua: correlation of different methods with the minimal fungicidal concentration.

Minimal inhibitory and minimal fungicidal concentrations of caspofungin were determined for 48 Candida inconspicua isolates. By using CLSI (formerly NCCLS) methodology with the partial inhibition endpoint criterion, caspofungin exhibited a good fungicidal effect against C. inconspicua (the MIC(90) was 0.25 microg/ml and the minimum fungicidal concentration [MFC] was 0.5 microg/ml after 24 h). Total inhibition yielded falsely elevated MICs, exceeding even the respective MFCs.

Antifungal Agents↗
PubMed1967

Laboratory examination of organic fungicides against zoopathogenic fungi in soil.

Seven commercial and five experimental organic fungicides were tested against Histoplasma capsulatum, Cryptococcus neoformans, Allescheria boydii, and Sporotrichum schenckii in a series of laboratory studies. Preliminary agar dilution plate tests indicated that Lanstan, DAC 649, DAC 469, DAC 2787, He 3944, maneb, and nabam, in order of decreasing activity, inhibited all test fungi. Terraclor, Dexon, and He 13274 were active only in high concentration. The best fungicidal properties were exhibited by Lanstan, Vapam, and DAC 649; maneb, nabam, DAC 469, and DAC 2787 were fungicidal but to a lesser degree than the former compounds. In subsequent tests against H. capsulatum and C. neoformans in artificially infested soil or by use of the buried plug technique, Lanstan, Vapam, and DAC 649 showed good activity and merit further study.

Antifungal Agents↗
PubMed2000

Human immunodeficiency virus type 1 infection of alveolar macrophages impairs their innate fungicidal activity.

Impaired adaptive immunity is the hallmark of AIDS, but the effects of human immunodeficiency virus type 1 (HIV-1) infection on innate immunity are less clear. Cryptococcus neoformans (CN) is a common AIDS-related fungal pathogen acquired by inhalation. Alveolar macrophages (AM) comprise the initial host defense in cryptococcosis and they may arrest infection before dissemination occurs. We hypothesized that HIV-1 infection of AM impairs their anti-cryptococcal activity. This was tested by infection of normal AM with the M-tropic strain HIV-1(Bal). Two weeks postinfection we measured fungistatic activity against CN by colony counting, binding, and internalization of CN by confocal microscopy and AM cell viability by Alamar Blue assay. Uninfected AM from most donors demonstrated innate fungicidal activity against CN. In HIV-1-infected AM, there was a significant reduction, and in most cases loss, of fungicidal activity compared with the uninfected AM. The reduced antifungal activity was not due to any cytotoxic effect of HIV-1, and HIV-1 infection did not impair binding or internalization of yeast by AM. Thus, the innate fungicidal activity of primary human AM is impaired after HIV-1 infection in vitro by a mechanism involving a defect of intracellular antimicrobial processing.

Cells, Cultured↗
PubMed1975

The fungicidal mechanisms of human monocytes. I. Evidence for myeloperoxidase-linked and myeloperoxidase-independent candidacidal mechanisms.

We tested the ability of human peripheral blood monocytes to kill Candida albicans and Candida parapsilosis. Evidence that multiple fungicidal mechanisms operate in normla monocytes was found. Normal monocytes ingested and killed viable C. albicans, and could iodinate heat-killed C. albicans. Both functions were defective in monocytes from subjects with myeloperoxidase deficiency or chronic granulomatous disease. Methimazole, isoniazid, and aminotriazole inhibited iodination by normal monocytes without impairing their ability to kill C. albicans, indicating that iodination was not essential to the myeloperoxidase-hydrogen peroxide-mediated fungicidal system of the monocyte. C. parapsilosis, an organism killed with supranormal efficacy by monocytes from a patient with hereditary myeloperoxidase deficiency, was selected to examine the myeloperoxidase-independent fungicidal mechanisms of monocytes. Monocytes were obtained from the blood of normal or leukemic subjects and homogenized in 0.34 M sucrose to yield fractions rich in cytoplasmic granules. These fractions were extracted with 0.01 M citric acid and the soluble components were separated by micropreparative polyacrylamide electrophoresis. Monocytes were found to contain cationic proteins, other than myeloperoxidase, that kill C. parapsilosis in vitro.

Anti-Inflammatory Agents↗
PubMed1989

Defective leukocyte fungicidal activity in end-organ resistance to 1,25-dihydroxyvitamin D.

Recent studies have shown 1,25(OH)2D3 receptor-mediated modulation of leukocyte proliferation, differentiation, and function. We examined the phagocytosis and killing of microorganisms by neutrophils and monocytes from five patients of three families with hereditary resistance to 1,25(OH)2D3. Phagocytosis of microorganisms by patients' neutrophils and monocytes was normal. However, defective neutrophil killing activity toward Candida albicans (30-40% of controls) was found in all patients. The killing of Staphylococcus aureus was normal. The neutrophil chemiluminescence, nitroblue tetrazolium (NBT) dye reduction, and the generation of superoxide ions and hydrogen peroxide by neutrophils and monocytes after induction by either soluble stimuli or zymozan particles, did not differ from those in controls. The neutrophil myeloperoxidase activity was also normal. Monocytes obtained from two patients of different families before long-term calcium infusion therapy and after they became normocalcemic, demonstrated a similar impaired fungicidal activity toward Saccharomyces cerevisiae, indicating that hypocalcemia itself was not the cause of the killing defect. However, the addition of the Ca+2 ionophore A23187 (1 microM) to the test medium restored the monocyte fungicidal activity to normal. As patients' neutrophil cytosolic free calcium concentration was similar to that in controls, it is suggested that 1,25-(OH)2D3 exerts its effect on leukocyte function by a putative receptor-mediated regulation of subcellular calcium localization which may be important for fungicidal activity.

Calcitriol↗
PubMed2006

In vitro fungistatic and fungicidal activities of silver sulfadiazine and natamycin on pathogenic fungi isolated from horses with keratomycosis.

OBJECTIVE: To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis. SAMPLE POPULATION: Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses. PROCEDURES: Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined. RESULTS: For all 17 fungal isolates, SSD MIC distribution ranged from < or = 1 to > 64 microg/mL; MIC50 and MIC90 (MICs at which 50% and 90% of organisms were inhibited) were 4 and 32 microg/mL, respectively. The SSD MFC distribution for all isolates was < or = 1 to > 64 microg/mL; MFC50 and MFC90 (MFCs at which 50% and 90% of organisms were killed) were 8 and > 64 microg/mL, respectively. For all fungal isolates, natamycin MIC distribution ranged from 256 to > 1,000 microg/mL; MIC50 and MIC90 were 512 and > 1,000 microg/mL, respectively. The natamycin MFC distribution for all isolates ranged from 512 to > 1,000 microg/mL; MFC(50) and MFC(90) were each > 1,000 microg/mL. CONCLUSIONS AND CLINICAL RELEVANCE: These in vitro data suggest that SSD is fungicidal against the fungal isolates that were obtained from eyes of horses with keratomycosis and that natamycin is fungicidal against some of the isolates at the drug concentrations evaluated. Silver sulfadiazine may be a therapeutic option for equine keratomycosis.

Animals↗
PubMed1996

Fungicidal effect of 15 disinfectants against 25 fungal contaminants commonly found in bread and cheese manufacturing.

Resistance of 19 mold and 6 yeast species to 15 commercial disinfectants was investigated by using a suspension method in which the fungicidal effect and germination time were determined at 20 degrees C. Disinfectants containing 0.5% dodecyldiethylentriaminacetic acid, 10 g of chloramine-T per 1, 2.0% formaldehyde, 0.1% potassium hydroxide, 3.0% hydrogen peroxide, or 0.3% peracetic acid were ineffective as fungicides. The fungicidal effect of quaternary ammonium compounds and chlorine compounds showed great variability between species and among the six isolates of Penicillium roqueforti var. roqueforti tested. The isolates of P roqueforti var. carneum, P. discolor, Aspergillus versicolor, and Eurotium repens examined were resistant to different quaternary ammonium compounds. Conidia and vegetative cells were killed by alcohols, whereas ascospores were resistant. Resistance of ascospores to 70% ethanol increased with age. Both P. roqueforti var. roqueforti and E. repens showed great variability of resistance within isolates of each species.

Bread↗
PubMed1991

[The natural killer and fungicidal activity of the peripheral blood mononuclear cells in candidiasis].

The activity of natural killers and the capacity of peripheral blood mononuclears for the extracellular killing of Candida cells in patients with different forms of candidiasis has been determined in the radiometric test with the use of targets labeled with 3H-uridine RNAase and in the fungicidal test. On the basis of the data thus obtained the conclusion has been made that in candidiasis changes in the activity of natural killers and fungicidal capacity depend on the severity of the disease and the stage of the process. Linear correlation between the activity of natural killers and fungicidal capacity in candidiasis patients at the stage of exacerbation and in healthy persons is absent.

Adolescent↗
PubMed1987

[Fungicidal effect of iodophor preparations on dermatophyte arthrospores].

The purpose of the investigations was to determine antifungal activity of iodophores: Pollena-Jod K and Mycofix. In vitro studies 3 strains of Trichophyton mentagrophytes from Sabouraud liquid medium and arthrospores of this fungus in skin scrapings obtained from sick foxes were examined. The in vivo fungicidal effect of the iodophores was studied in foxes and in young bulls, where 5 and 10% solutions of the preparations were used three times. It was found that the exact inactivation of arthrospores is possible when 8-fold or even 10-fold higher concentrations of the preparations were used than that used for inactivation of vegetative cells. After 1 h exposition vegetative cells were destroyed by 0.4% solution of Pollena-Jod K or Mycofix, however, 5% solution of Pollena-Jod K and 3% solution of Mycofix destroyed arthrospores. In the field studies Mycofix revealed higher fungicidal effects. The index of isolation of the fungus from skin scrapings for animals treated with Mycofix was lower by 38% in comparison to that for animals treated with Pollena-Jod K. Despite three times application of 5% and 10% solutions of the examined iodophores on fungal foci in animals, a part of arthrospores survived. For the determination of fungicidal activity of antimycotic drugs used to prevent or control of dermatomycoses, arthrospores present in skin scrapings of sick animals may be used.

Animals↗
PubMed1999

The toxicity of dithiocarbamate fungicides to soil nematodes, assessed using a stress-inducible transgenic strain of Caenorhabditis elegans.

The dithiocarbamate fungicides maneb and mancozeb induce a short-term stress response in a transgenic Caenorhabditis elegans strain (PC72) carrying a reporter lacZ gene under the control of a homologous heat shock (hsp16) promoter. This response can be readily monitored as induced beta-galactosidase activity, either by in situ staining or by a quantitative fluorometric enzyme assay. Particularly strong responses are induced by mancozeb (three- to fivefold above controls at 500 microg mL(-1)), causing acute toxicity at concentrations comparable to those recommended for field application (2 mg mL(-1)). Although much of this fungicide is adsorbed by soil, sufficient (ca. 6%) enters the soil water compartment to cause mild stress in the transgenic worm assay. Among possible metabolites from mancozeb breakdown, neither Mn2+ nor ethylenethiourea (ETU) is particularly toxic even at 10% of the optimum mancozeb dosage. Stress responses to a range of other pesticides are also reported, and in several cases it is clear that a nontarget soil species (here, transgenic C. elegans) may be sensitive to low-level contamination.

Animals↗
PubMed2007

The direct chiral separations of fungicide enantiomers on amylopectin based chiral stationary phase by HPLC.

Amylopectin-tris(phenylcarbamate) was synthesized and coated to aminopropylsilica to prepare chiral stationary phase. The chiral separations of fungicide enantiomers were performed by the CSP using high-performance liquid chromatography. Mobile phase was n-hexane and isopropanol, and flow rate was 1.0 ml/min. Detection wavelength was 230 nm. The influence of the percentage of isopropanol in the mobile phase on the separations was studied. Twelve chiral fungicides were tested and seven of them were found to show stereoselectivity on the CSP. The enantiomers of metalaxyl and benalaxyl got near baseline separations and myclobutanil, hexconazole, tebuconazole, uniconazole, and paclobutrazol enantiomers were completely separated. The decreasing percentage of isopropanol in the mobile phase resulted in better separation and longer analysis time. The enantiomers were identified by a circular dichroism (CD) detector and the CD spectra of the individual enantiomers were also studied by online scanning.

Amylopectin↗