Isolates Of Filamentous Fungi Research Articles

Antifungal activity of a new triazole, voriconazole (UK-109,496), compared with three other antifungal agents tested against clinical isolates of filamentous fungi

Antifungal activity of a new triazole, voriconazole (UK-109,496), compared with three other antifungal agents tested against clinical isolates of filamentous fungi

Activity of BAL 4815 against filamentous fungi

BAL 4815 is a new antifungal drug and it is the active component of the antifungal triazole BAL 8557 (the water-soluble precursor). We studied the in vitro fungistatic and fungicidal activities of BAL 4815 against 103 clinical isolates of filamentous fungi, including 51 isolates of Aspergillus spp. and 52 isolates of non-Aspergillus filamentous fungi. We evaluated the in vitro activity of BAL 4815 against 51 isolates of Aspergillus spp., 20 isolates of dematiaceous fungi, 18 isolates of hyaline Hyphomycetes and 14 isolates of Zygomycetes. MICs were determined following the CLSI M38-A broth microdilution method, using RPMI 1640 medium buffered to pH 7.0 with MOPS. Microdilution plates were incubated at 35 degrees C and read at 24 and 48 h (Mucorales were read at 24 h). Minimal fungicidal concentrations were also determined. For all isolates, geometric mean MICs, MIC(50)s, MIC(90)s and MIC ranges (mg/L) were: Aspergillus spp., 1.67, 2, 4 and 0.5-4; dematiaceous fungi, 1.62, 1, >8 and 0.03 to >8; hyaline Hyphomycetes, 2.41, 2, >8 and 0.03 to >8; and Zygomycetes, 6.81, 8, >8 and 0.03 to >8. Differences in susceptibility between genera were noted. Scedosporium prolificans, Fusarium spp., Mucor spp. and Rhizopus spp. (MIC(90) > 8 mg/L) were less susceptible than Aspergillus spp. (MIC(90) = 4 mg/L). BAL 4815 has excellent in vitro activity against Aspergillus spp. and variable activity against other filamentous fungi.

Incidence and distribution of filamentous fungi during fermentation, drying and storage of coffee (Coffea arabica L.) beans.

The objective of this work was to isolate and characterize filamentous fungi present in different stages of harvest, fermentation, drying and storage of coffee beans processed by natural method. The cherries were hand-picked and then placed on a cement drying platform where they remained until reached 11% of humidity. Microbial counts were found in all samples during fermentation and drying of the coffee beans. Counts of fungi in the coffee cherries collected from the tree (time 0) were around 1.5 x 103 CFU/g. This number increased slowly during the fermentation and drying reaching values of 2 x 105 CFU/g within 22 days of processing. Two hundred and sixty three isolates of filamentous fungi were identified. The distribution of species during fermentation and drying was very varied while there was a predominance of Aspergillus species during storage period. The genera found were Pestalotia (4), Paecelomyces (4), Cladosporium (26), Fusarium (34), Penicillium (81) and Aspergillus (112) and comprised 38 different species.

MICROBIAL INTERACTIONS WITH MYCOTOXIGENIC FUNGI AND MYCOTOXINS

Mycotoxins such as aflatoxins, fumonisins, trichothecenes, and ochratoxins are contaminants of many agronomic crops worldwide, and cause both economic losses and health effects. The potential of antagonistic microorganisms to be developed into biological control agents has been investigated in several crop systems, as alternatives to chemical fungicides for control of mycotoxigenic fungi. Laboratory and greenhouse studies have identified a number of bacterial, yeast, and filamentous fungal isolates that reduce crop contamination of mycotoxigenic fungi, although investigations of field efficacy have been limited. These studies demonstrate that the diversity of ecological interactions between mycotoxigenic fungi and other resident microorganisms may provide tools for development of biocontrol methods to reduce mycotoxin contamination.

Newer Emerging Pathogens of Ocular Non-Sporulating Molds (NSM) Identified by Polymerase Chain Reaction (PCR)-Based DNA Sequencing Technique Targeting Internal Transcribed Spacer (ITS) Region

Purpose: To apply Polymerase Chain Reaction (PCR)-based DNA sequencing targeting Internal Transcribed Spacer (ITS) region for identification of non-sporulating molds (NSM) to species level which formed 12% of ocular isolates of fungi in a tertiary eye hospital in South India. Materials and Methods:Fifty ocular filamentous fungal NSM isolates recovered from 45 patients were included in the study. PCR-based DNA sequencing technique targeting ITS region was applied to identify NSM. Results: PCR-based DNA sequencing revealed 23 established pathogens involving 8 genera (Aspergillus, Fusarium, Bipolaris, Pythium, Cochilobolus, Exserohilum, Pseudoallescheria, and Scedosporiumspecies) and 27 emerging pathogens involving 7 genera (Botryosphaeria Lasiodiplodia species, Thielavia tortuosa, Glomerulla singulata, Macrophomina phaseolina, Rhizoctonia bataticola, and Podosporaspecies) reported for the first time in literature related to ocular infections. Fifteen (30%) patients with fungal keratitis caused by NSM failed to respond to standard antifungal therapy. Conclusion: PCR-based DNA sequencing technique is a rapid, reliable, and valuable tool to identify 54% of NSM as newer potential pathogens of fungi causing ocular mycoses.

A radiochemical technique with potential for revealing novel fungal metabolites according to expression of specific biosynthetic activities

Fungal secondary metabolites are mostly derived from a few key intermediates in primary metabolism, such as acetate and some amino acids. Classical screens for novel fungal compounds of possible industrial interest have used chromatographic displays of extract components, as was the practice for plant natural products, followed by structural determination and pharmacological study. In contrast, modern robotic screens usually focus initially on specific bioassay applied to fermentation products and crude extracts. Both strategies are expensive in terms of human resources and/or in sophisticated equipment. A relatively inexpensive technique, exploiting biosynthetic principles through use of 14C-labelled probes to recognise particular structural features by autoradiography of tlc plates is described and discussed. Application to 80 isolates of filamentous fungi from Caribbean and European/Mediterranean environments enabled recognition of arrays of metabolites according to their biosynthetic origin, showing the potential of the technique in novel product discovery in unsophisticated laboratory facilities, as exemplified by reference to subsequent discovery of novel metabolites produced by Amorosia littoralis.

Isolation of filamentous fungi from public telephones of the Metropolitan region of the city of Recife, PE, Brazil

Fungi can inhabit our organism without causing any harm, but they show themselves when the immunological system is compromised. In this study, a survey of the occurrence of filamentous fungi was carried out in public telephones of the Metropolitan Region of the City of Recife, PE, Brazil. This showed the public phones as a possible mean of transmission of fungal diseases among humans. Samples from the environment, audios, speakers and keyboards were taken at the airport, mall, subway and bus station in the months of October/2003 (dry season) and June/2004 (rainy season), totaling 120 samples. The procedure of identification of species was carried out through conventional taxonomy. Thirty-four genera were isolated, totaling 73 species, the majority belonging to the anamorphic fungi (91.78%), followed by the Ascomycota (6.85%) and the Zygomycota (1.37%). There was no significant difference in the proportion of species between the dry and rainy seasons, with 46 and 53 species identified, respectively. Due to the lack of maintenance, or inadequate cleaning of public telephones, the fungi present in these appliances may cause mycosis in the users as these telephones are used by people from different social classes and variable habits, both healthy and immunocompromised.

Evaluation of Disk Diffusion and Etest Compared to Broth Microdilution for Antifungal Susceptibility Testing of Posaconazole against Clinical Isolates of Filamentous Fungi

We performed Etest, disk diffusion, and broth microdilution susceptibility testing of posaconazole against 146 clinical isolates of filamentous fungi. By using provisional breakpoints for comparison purposes only, categorical agreement between the results of the agar-based methods and those of broth microdilution were 96 to 98%, with no very major errors. These agar-based methods hold promise as simple and reliable methods for determining the posaconazole susceptibilities of filamentous fungi.

Risk Factors for PulmonaryAspergillus terreusInfection in Patients With Positive Culture for Filamentous Fungi

Background:Invasive aspergillosis (IA) is a common fungal infection in immunocompromised patients and has a high mortality rate. Among patients with IA,Aspergillus terreusinfections have become a growing concern in the past few years.Objective:To determine the clinical risk factors for isolation of and respiratory infection byA terreusin patients with culture findings positive for filamentous fungiMethods:Cohort study of 505 consecutive isolates of filamentous fungi in 332 patients from one center.A terreuswas present in 46 isolates from 40 patients (9.1%). Clinical histories were reviewed to identify the risk factors related to isolation of and infection byA terreus, which were grouped into three categories (ie, host factors, factors related to immunosuppression, and factors related to hospitalization), and were analyzed using a multiple logistic regression model.Results:A total of 192 of 505 isolates studied (38%) were due to invasive respiratory infection. A total of 27 of 46 cultures (58.7%) that were positive forA terreuswere due to invasive infection (odds ratio [OR], 2.53; 95% confidence interval [CI], 1.37 to 4.69; p = 0.034). The factors associated with invasiveA terreusinfection were prophylactic use of amphotericin B aerosols (OR, 27.8; 95% CI, 6.7 to 109.7; p = 0.001) and mechanical ventilation (OR, 3.3; 95% CI, 1.02 to 10.9; p = 0.04). Transplantation was associated with a lower risk ofA terreusinfection (OR, 0.2; 95% CI, 0.046 to 0.789; p = 0.02).Conclusions:In patients with culture findings positive for filamentous fungi, the prophylactic use of amphotericin B aerosols and mechanical ventilation are associated with a higher risk ofA terreusinfections. In these patients, transplantation is associated with a lower risk of isolation and respiratory infection byA terreus.

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

To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis. Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses. 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. 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. 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.

Screening mitosporic fungi for organochlorides degradation

Fifty-five isolates of filamentous fungi were studied regarding their ability to decolorize Remazol brilliant blue R dye. The fungi were isolated from soil in the Baixada Santista region, which is contaminated with industrial residues containing a mixture of organochlorine compounds, mainly hexachlorobenzene. The fungi were grown in liquid malt extract medium with 0.02% of dye and shaken at 200 rpm for 14 days at 28 ± 2oC. Two types of behavior regarding the dye were observed: adsorption and degradation. Eupenicillium baarnenseSsp1951 and Ssp1952 and Eupenicilliumcrustaceum SSP1953 presented high RBBR decolorization and were then analyzed regarding their ability to degrade 14C-hexachlobenzene (4138.31 mg HCB per kg soil) during a 56 days culture at 28 ± 2oC. Eupenicillium crustaceum SSP1953 was able to reduce n-hexane soluble 14C-compounds (24.6%) and to form non-extractable 14C-residues (20.5%). The same behavior was also observed in the two E. baarnense strains (Ssp1951 and Ssp1952) but the percentages were lower than those obtained for Eupenicilliumcrustaceum. The main action of Eupenicillium spp on HCB is to transform it into non-extractable 14C-residues as confirmed by the gas chromatography results.

Nickel Tolerance and Accumulation by Filamentous Fungi From Sludge of Metal Finishing Industry

Industrialization, urbanization and increased vehicular traffic have resulted in increased contamination of our environment by heavy metals. The long persistence of heavy metals in nature has in turn resulted in development of metal resistant microbial strains. These strains are minimizing heavy metals toxicity, either by metal complexation or precipitation and other mechanisms. Characterization of fungal diversity was done in contaminated soil of the Wazirpur industrial area throughout the year. In this area highly acidic hazardous solid waste produced high concentration of heavy metals (Ni, Cu, Cr, Fe, Mn). Nickel toxicity is a major environmental concern. Due to long persistence of this waste in the environment without any treatment, many fungal isolates from the surrounding environment settle on the upper surface of waste. Few of them are capable of growing in the toxic conditions. More than 20 strains were isolated, most of them belonging to species of Aspergillus, Penicillium, Fusarium and Mucor genera. Seasonal variation in fungal diversity was significant. Four filamentous fungal isolates were found to be resistant for nickel (II) and a strain of Papulaspora sepedonoides reported first time for bioremediation of Ni (II) in this investigation, which is absorbing 62.33 μmol Ni gr−1. These fungal isolates showed a high level (100–10000 mg kg−1) of resistance for Ni (II) salt and removing Ni (II) from solution. Metal uptake varied with fungi. The toxicity also was influenced by different factors like pH and composition of growth medium.

Voriconazole in the management of nosocomial invasive fungal infections

Voriconazole is a new triazole developed for the treatment of life-threatening fungal infections. The drug is available for both oral and intravenous administration; the oral formulation has excellent bioavailability. The side-effect profile of voriconazole presents an acceptable safety and tolerability spectrum: transient visual disturbances, liver enzyme abnormalities, and skin rashes are the most frequently reported side effects but rarely lead to discontinuation. The potential for drug-drug interactions is high, because of its extensive hepatic metabolism. Careful attention to dosage is required, and serum levels and the effects of interacting drugs should be monitored. Review of 25 470 isolates of yeasts and 3216 isolates of filamentous fungi showed voriconazole to have broad-spectrum activity against pathogenic yeasts including intrinsically fluconazole-resistant isolates such as Candida krusei, dimorphic fungi, and opportunistic moulds like Aspergillus spp, amphotericin-B-resistant Aspergillus terreus, Fusarium spp, and Scedosporium apiospermum. It displays excellent clinical efficacy in patients with fluconazole-resistant and -susceptible Candida infections, invasive bone and central nervous system aspergillosis, and various refractory fungal infections. Voriconazole has been approved by the US Food and Drug Administration and by the European Medicines Agency for the treatment of invasive aspergillosis, serious infections caused by Fusarium and S. apiospermum, fluconazole-resistant invasive Candida infections, and candidemia in nonneutropenic patients.

The effect of propyl gallate on the activity of various antifungal drugs against filamentous fungi in vitro

The influence of an antioxidant, propyl gallate (PG), on the activity of amphotericin B (AMB), terbinafine (TBF), butenafine (BTF) and ketoconazole (KCZ) against ocular pathogenic filamentous fungi in vitro was investigated to determine whether PG could increase the antifungal activity. Susceptibility tests were performed against 6 isolates of ocular pathogenic filamentous fungi (Fusarium solanae, Fusarium moniliforme, Fusarium poae, Fusarium oxysporum, Aspergillus fumigatus and Aspergillus flavus) and 2 quality control strains (Candida krusei ATCC 6258 and Cadida parapsilosis ATCC 22019) by the NCCLS M38-P broth microdilution method (MIC). PG was added to the incubation media at a final concentration of 400 microg/ml. Antifungal agents were serially two-fold diluted and final dilutions were made in 1640 and PG-1640 culture media to a concentration ranging from 0.0313 to 16 microg/ml for AMB, TBF, BTF and KCZ. One hundred microl of the corresponding diluted inoculum suspension was added to each well of the microdilution tray. The MIC end-point of AMB was determined as 100% growth reduction and the MIC end-point of TBF, BTF, KCZ and PG was determined as 75% growth reduction as compared with the turbidity produced by the control well. At a concentration of 400 microg/ml, PG did not show any antifungal activity under these experimental conditions. The combination of PG (400 microg/ml) with amphotericin B revealed a remarkably increased activity against all of the isolates of ocular pathogenic filamentous fungi and quality control strains. In the combination of PG with terbinafine, a remarkably increased activity was observed against Fusarium solanae, Fusarium poae, Fusarium oxysporum, Aspergillus fumigatu and Aspergillus flavus. The combination of PG with butenafine had remarkably synergistic effect against Fusarium solanae, but did not synergistic or even showed antagonistic effect for other isolates. The combination of PG with ketaconazole was synergistic against Fusarium solanae, but was antagonistic against all other isolates. Combination of PG and amphotericin has remarkably synergistic effect against all tested ocular pathogenic filamentous fungi isolates. Combination of PG and terbinafine has remarkably synergistic effect against some isolates. The PG-amphotericin combination and the PG-terbinafine combination may have a role in future studies of antifungal eye drops.

Endoglucanase‐producing fungi isolated from Cape Evans historic expedition hut on Ross Island, Antarctica

Early explorers of Antarctica's Heroic Era erected wooden buildings and brought large quantities of supplies to survive in Antarctica. The introduction of wood and other organic materials provided nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials and adapted to the harsh conditions. Seventy-two isolates of filamentous fungi were cultured on selective media from interior structural wood of the Cape Evans historic hut and 27 of these screened positive for the ability to degrade carboxymethyl cellulose (CMC). Four non-CMC-degrading isolates were added to a group of 14 CMC-degrading isolates for further study, and endo-1, 4-beta-glucanase activity was demonstrated in the extracellular supernatant from all of these 18 isolates when grown at 4 degrees C, and also when they were grown at 15 degrees C. Isolates of Penicillium roquefortii and Cadophora malorum showed preference for growth at 15 degrees C rather than 25 degrees C or 4 degrees C indicating psychrotrophic characteristics. These results demonstrate that cellulolytic filamentous fungi found in Antarctica are capable of growth at cold temperatures and possess the ability to produce extracellular endo-1, 4-beta-glucanase when cultured at cold and temperate temperatures.

Effect of Voriconazole Combined with Micafungin against Candida , Aspergillus , and Scedosporium spp. and Fusarium solani

Effects of voriconazole combined with micafungin against 101 isolates of Candida spp. and 100 isolates of filamentous fungi have been evaluated by in vitro checkerboard analysis. The combination was indifferent for 97% of the Candida isolates and synergistic for 64% of the filamentous fungi (79% for Aspergillus fumigatus).

Fungal DNA Challenge in Human STR Typing of Bone Samples

The present study focuses on possible cross-reaction of fungal DNA with human STR primers that may affect subsequent forensic DNA analysis of forensic samples. Specificity of human STR markers namely HUMAMEL, HUMCSF1PO, D8S306, HUMTH01, HUMvWA, HUMFES/FPS, HUMF13A01, HUMDHFRP2, HUMFGA and HUMTPOX was tested using DNA of 24 different filamentous fungal isolates obtained from exhumed bone samples. The specificity of these ten STR markers for human DNA was demonstrated. Presence of non-human DNA in five bone samples analyzed did not alter scoring of detected alleles. Notably, amplification was inhibited in the presence of a high proportion of fungal DNA compared to human DNA (1000 ng: 1 ng) in DNA mixture experiments. The results of the present study underscore the importance of carefully analyzing the presence of non-human biological contaminants that may affect DNA typing of environmentally challenged forensic samples to avoid spurious data interpretation.

Mycoflora of the 'green water' culture system of tiger shrimp Penaeus monodon Fabricius

This study was conducted to quantify and characterize the mycoflora associated with the ‘green water’ culture system of Penaeus monodon. Samples of water, tilapia gut and mucus, and shrimp hepatopancreas from three shrimp farms were collected during 15, 30, 45 and 60 days of culture (DOC). Results showed that high fungal loads were observed in tilapia gut (total: 117–1352 colony forming unit (CFU) 5 cm hind gut−1; yeasts: 0–136 CFU 5 cm hind gut−1) and mucus (total: 12–311 CFU (5 cm2)−1; yeasts: 0–88 CFU (5 cm2)−1), while minimal fungal populations were observed in water samples (total: 0–110CFU mL−1; yeasts: 0–5 CFU ml−1). Shrimp hepatopancreas harboured a very low number of filamentous fungi (0–27 CFU 0.1 g−1) and yeasts (0–7CFU 0.1 g−1) especially at 60 DOC. The filamentous fungal isolates were dominated by Penicillium and Aspergillus species, while the yeast populations were dominated by Rhodotorula and Saccharomyces species. The dominance of these fungi on tilapia mucus and gut and their presence in the rearing water might play an important role in the overall mechanisms involved in the control of luminous Vibrio in the ‘green water’ grow-out culture of P. monodon.

Sewage Treatment Plant Sludge: A Source of Potential Microorganism for Citric Acid Production

This research emphasizes on the utilization of Sewage Treatment Plant (STP) sludge, which is an inexpensive and easily available raw material and a good source for growth of microorganisms because it has enough nutrients and trace elements. This can be considered as an alternative cost effective solution for waste management in addition to the production of a value added product citric acid, one of the important chemicals used in various industrial processes. The isolation of filamentous fungi especially Aspergillus was made from STP sludge for better adaptability. Six strains of Aspergillus were isolated from STP sludge and identified using slide culture technique followed by image analysis. Four strains (SC906, A103, A2017 and A1020) were selected from lab stock. All strains were screened under controlled fermentation conditions such as pH range of 2-3, temperature 30°C and agitation 150 rpm, using 1% (w/w) of substrate (STP sludge), 2% (w/w) co-substrate (wheat flour) with inoculum’s size of 2% (spore mL?1), using a liquid state fermentation process for the maximum production of citric acid. Evaluation of fungal potentiality was done in terms of maximum citric acid production, biosolids production (TSS %) and Chemical Oxygen Demand (COD) removal. Strain A-SS106 produced the highest concentration of citric acid (0.14 g L?1), TSS (15.18 g L?1) and COD removal (90.1%) on the fourth day of fermentation.

Estudio de la sensibilidad in vitro de aislamientos clínicos de mohos y levaduras a itraconazol y voriconazol

The interest on the in vitro susceptibility to itraconazole has recently increased due the availability of the intravenous formulation. In this study, comparative MICs of this antifungal with voriconazole were carried out in 62 clinical isolates of filamentous fungi and 100 yeasts isolates using the NCCLS microbroth methods described in M38-A and M27-A2 documents. A MIC90 of 0.125 micrograms per ml was observed for itraconazole and voriconazole against Aspergillus fumigatus. Higher susceptibility to itraconazole was found for the filamentous form of Sporotrhix schenckii (p = 0.001). Voriconazole was more effective against Scedosporium apiospermium while Scedosporium prolificans isolates were resistant to both azoles. Some isolates of Rhizopus stolonifer were susceptible to itraconazole and resistant to voriconazole, but without statistical significance. Susceptibility of nine species of Candida was similar for both triazoles used in this study. However, Candida glabrata was more susceptible to voriconazole. Some fluconazole-resistant Candida albicans isolates were susceptible to itraconazole and / or voriconazole. Cryptococcus neoformans was more susceptible to itraconazole than to voriconazole. Itraconazole and voriconazole showed very close in vitro activity against the tested fungal isolated, except against S. schenckii. In spite of this, there were some differences in susceptibility among isolates within the same fungal species.