Prevalence Of Fungi Research Articles

Using the gamma concept in modelling fungal growth: A case study on brioche-type products

Fungi are common spoilers of intermediate moisture foods such as bakery products. Brioche are bakery products prone to fungal spoilage due to their pH (5.8–6.2) and water activity (aw) (0.82–0.84). The aims of the present study were: (i) the identification of fungal species occurring in brioche products, (ii) the in vitro assessment of their growth potential, and (iii) the development of a validated growth model following the gamma concept. A total of 102 fungal strains were isolated, with Penicillium sp., Cladosporium sp., and Aspergillus sp. being the main genera, representing 90% of the isolates. Given the isolation frequency, any potential fungal prevalence throughout the bakery processs and/or the results of in vitro assessment of fungal growth potential under conditions mimicking brioche (pH, aw, temperature), Aspergillus flavus, Aspergillus fumigatus, and Penicillium sp. were selected for the development of the gamma model. According to in vitro validation, the model successfully predicted fungal growth, while on in situ experiments, the intrinsic parameters (aw and/or level of used preservative) of brioche in combination with packaging conditions (modified atmosphere) did not allow fungal growth.

Micafungin Enhances the Human Macrophage Response to Candida albicans through β-Glucan Exposure.

Micafungin belongs to the antifungal family of echinocandins, which act as noncompetitive inhibitors of the fungal cell wall β-1,3-d-glucan synthase. Since Candida albicans is the most prevalent pathogenic fungus in humans, we study the involvement of micafungin in the modulation of the inflammatory response developed by human tissue macrophages against C. albicans The MIC for micafungin was 0.016 μg/ml on the C. albicans SC5314 standard strain. Micafungin induced a drastic reduction in the number of exponential SC5314 viable cells, with the fungicidal effect being dependent on the cellular metabolic activity. Notably, micafungin also caused a structural remodelling of the cell wall, leading to exposure of the β-glucan and chitin content on the external surface. At the higher doses used (0.05 μg/ml), the antifungal also induced the blowing up of budding yeasts. In addition, preincubation with micafungin before exposure to human tissue macrophages enhanced the secretion of tumor necrosis factor alpha (TNF-α), interleukin-17A (IL-17A), and IL-10 cytokines. Our results strongly suggest that in C. albicans treatment with micafungin, in addition to having the expected toxic antifungal effect, it potentiates the immune response, improving the interaction and activation of human macrophages, probably through the unmasking of β-glucans on the cell wall surface.

Prevalence and characterization of azole-resistant Aspergillus fumigatus in patients with cystic fibrosis: a prospective multicentre study in Germany.

Aspergillus fumigatus is the most prevalent filamentous fungus in the respiratory tract of patients with cystic fibrosis (CF). The aim of this prospective multicentre study was to investigate the prevalence of azole-resistant A. fumigatus (ARAF) in respiratory secretions from CF patients across Germany and to characterize ARAF isolates by phenotypic and molecular methods. Twelve tertiary care centres from Germany participated in the study. In total, 2888 A. fumigatus isolates from 961 CF patients were screened for ARAF by using azole-containing agar plates. Antifungal susceptibility testing of isolates was performed by broth microdilution according to EUCAST guidelines. Analysis of mutations mediating resistance was performed using PCR and sequencing of the cyp51A gene. Furthermore, genotyping by microsatellite PCR was performed. Of a total of 2888 A. fumigatus isolates, 101 isolates from 51 CF patients were found to be azole resistant (prevalence per patient 5.3%). The Essen centre had the highest prevalence (9.1%) followed by Munich (7.8%), Münster (6.0%) and Hannover (5.2%). Most ARAF isolates (n = 89) carried the TR34/L98H mutation followed by eight G54E/R, one TR46/Y121F/T289A and one F219S mutation. In two isolates no mutation was found. Genotyping results showed no major clustering. Forty-five percent of CF patients with ARAF had previously received azole therapy. This is the first multicentre study analysing the prevalence of ARAF isolates in German CF patients. Because of a resistance rate of up to 9%, susceptibility testing of A. fumigatus isolates from CF patients receiving antifungal treatment should be part of standard diagnostic work-up.

Association of Caliciopsis pinea Peck and Matsucoccus macrocicatrices Richards with eastern white pine (Pinus strobus L.) seedling dieback

Matsucoccus macrocicatrices Richards (Hemiptera: Matsucoccidae) is the only species within this genus that feeds and reproduces on eastern white pine (Pinus strobus L.), and at the time of its description, was not observed or known to cause serious damage. With eastern white pine dieback occurring extensively throughout the Appalachian Mountains, researchers are now in search of the contributors to this dieback phenomenon. Since its recent discovery (2007) far outside its historical range, M. macrocicatrices, and cankers associated with Caliciopsis pinea Peck, are regularly present on symptomatic trees throughout the range of eastern white pine. Little is known about the relationship between M. macrocicatrices and the fungal cankers commonly found on eastern white pines expressing dieback symptoms. For this study, we evaluated the relationships between both focal organisms and the extent of dieback symptoms on tree seedlings to identify contributing factors affecting symptomatic trees. We assessed the insect-pathogen complex on 270 eastern white pine seedlings from nine states that include the Appalachian Mountain range. There were positive correlations between M. macrocicatrices and seedling dieback, cankers and seedling dieback, and M. macrocicatrices and cankers in both the southern and northern portions of the Appalachians. About 95% of the observed M. macrocicatrices cysts and shells were associated with cankers, especially C. pinea-dominated cankers, which were exceptionally abundant on severely affected seedlings. The most prevalent fungi isolated from cankers without apparent fruiting bodies of C. pinea were in the genus Phaeomoniella. Trials were conducted to test the pathogenicity of C. pinea and other fungal isolates. Of the 15 fungal species tested, C. pinea was the only pathogenic species that formed girdling cankers on eastern white pine seedlings. We postulate that there is a facultative relationship between M. macrocicatrices and C. pinea, forming an insect-pathogen complex that is contributing to eastern white pine dieback and significantly impacting its regeneration dynamics in North America.

Fungal Infection Associated with denture

Candida is a genus of yeast .Many species of this genus are symbiont of animalshost including humans. While usually living as commensally in oral cavity, somecandida can cause disease .The most significant member of the genus is candidaalbicans which can cause infection called candidiasis or thrush especially in elderlydenture wearers.So the denture seems to be frequently the sources of fungal infection.The current study aimed to determine the fungal prevalence rate in oral cavityamong denture wearers patients in comparison to those without dentures and also todetermine the local risk factors includes trauma due to ill fitting denture, nocturnalwear of the denture, heavy smoking and the age of the denture.The result of this study showed that the prime etiology of candida growth was thematerial of prosthesis itself. 57% of the denture wearers showed growth of candidawhile 22% of subjects who had their own dentitions showed candida growth that theprosthesis is the dominant etiological factors in candida growth other local factorsmust be considered.

Microbiological analysis of bioaerosols collected from Hospital Emergency Departments and ambulances.

The goal of the study was a microbiological, qualitative and quantitative analysis of bioaerosol at the workplace of medical personnel (Health Emergency Departments (HEDs), ambulances), and comparative administration offices with an expected neutral occupational exposure to biological agents measured with individual Button Sampler. Personal sampling was performed with Button Sampler instrument loaded with gelatine filters in 10 HEDs, in 9 ambulances and in 9 offices to assess the occupational biological agents' exposure in air. Sampling was conducted from March until April 2016. Samples were quantitatively assessed for viable and total number of bacteria and fungi. Routine procedures for microbiological diagnostics were implemented. Data were analysed using Kruskal-Wallis and Mann-Whitney statistical tests with α=0.05. P value less than 0.05 were considered significant. At the workplaces assessed, the concentrations of viable microorganisms in HEDs were 1.3×102 - 4.2×103 CFU/m3 for bacteria, 3.4×100 - 8.1×101 CFU/m3 for fungi; in ambulances 1.3×102 - 1.4×103 CFU/m3 (bacteria), 6.7×100 - 6.5×102 CFU/m3 (fungi) and in offices 4.2×101 - 5.0×103 CFU/m3 (bacteria), 0 - 7.9×102 CFU/m3(fungi). In outdoor air, the number of microorganisms reached the level: 1.0×102 - 5.9×102 CFU/m3 for bacteria and 1.5×102 - 8.2×102 CFU/m3 for fungi. The predominant isolated bacteria were Gram-positive cocci. The prevalent fungi species belonged to the genus Aspergillus and Penicillium. The quantitative assessment of examined indoor air was similar to control outdoor air, and were relatively low. The level of microbiological contamination did not exceed 5×103 CFU/m3 which is recommended as an admissible level in public spaces in Poland.

Identification and Pathogenicity of Fungal Pathogens Causing Black Point in Wheat on the North China Plain.

Fungi associated with black point were isolated from three highly susceptible wheat genotypes in the North China Plain. The 21 isolates represented 11 fungal genera. The most prevalent genera were Alternaria (isolation frequency of 56.7%), Bipolaris (16.1%), and Fusarium (6.0%). The other eight genera were Curvularia, Aspergillus, Cladosporium, Exserohilum, Epicoccum, Nigrospora, Penicillium, and Ulocladium; their isolation frequencies ranged from 0.8 to 4.8%. The pathogenicity of the isolates was individually assessed in the greenhouse by inoculating wheat plants with spore suspensions. Ten of the 21 isolates caused significantly higher incidences of black point than that the controls. These isolates belonged to eight fungal species (A. alternata, B. sorokiniana, B. crotonis, B. cynodontis, C. spicifera, F. equiseti, E. rostratum, and E. sorghinum) based on morphological traits and phylogenetic analysis. The average incidences of black point in the eight fungal species were 32.4, 54.3, 43.0, 41.9, 37.2, 38.8, 50.1, and 34.1%, respectively. B. sorokiniana and A. alternata were determined to be the most important pathogens in the North China Plain based on fungal prevalence and symptom severity. This study is the first to identify E. rostratum as a major pathogen causing black point in wheat.

Fungi in Bronchiectasis: A Concise Review.

Although the spectrum of fungal pathology has been studied extensively in immunosuppressed patients, little is known about the epidemiology, risk factors, and management of fungal infections in chronic pulmonary diseases like bronchiectasis. In bronchiectasis patients, deteriorated mucociliary clearance—generally due to prior colonization by bacterial pathogens—and thick mucosity propitiate, the persistence of fungal spores in the respiratory tract. The most prevalent fungi in these patients are Candida albicans and Aspergillus fumigatus; these are almost always isolated with bacterial pathogens like Haemophillus influenzae and Pseudomonas aeruginosa, making very difficult to define their clinical significance. Analysis of the mycobiome enables us to detect a greater diversity of microorganisms than with conventional cultures. The results have shown a reduced fungal diversity in most chronic respiratory diseases, and that this finding correlates with poorer lung function. Increased knowledge of both the mycobiome and the complex interactions between the fungal, viral, and bacterial microbiota, including mycobacteria, will further our understanding of the mycobiome’s relationship with the pathogeny of bronchiectasis and the development of innovative therapies to combat it.

A survey on cellular RNA editing activity in response to Candida albicans infections

BackgroundAdenosine-to-Inosine (A-to-I) RNA editing is catalyzed by the adenosine deaminase acting on RNA (ADAR) family of enzymes, which induces alterations in mRNA sequence. It has been shown that A-to-I RNA editing events are of significance in the cell’s innate immunity and cellular response to viral infections. However, whether RNA editing plays a role in cellular response to microorganism/fungi infection has not been determined. Candida albicans, one of the most prevalent human pathogenic fungi, usually act as a commensal on skin and superficial mucosal, but has been found to cause candidiasis in immunosuppression patients. Previously, we have revealed the up-regulation of A-to-I RNA editing activity in response to different types of influenza virus infections. The current work is designed to study the effect of microorganism/fungi infection on the activity of A-to-I RNA editing in infected hosts.ResultsWe first detected and characterized the A-to-I RNA editing events in oral epithelial cells (OKF6) and primary human umbilical vein endothelial cells (HUVEC), under normal growth condition or with C. albicans infection. Eighty nine thousand six hundred forty eight and 60,872 A-to-I editing sites were detected in normal OKF6 and HUVEC cells, respectively. They were validated against the RNA editing databases, DARNED, RADAR, and REDIportal with 50, 80, and 80% success rates, respectively. While over 95% editing sites were detected in Alu regions, among the rest of the editing sites in non repetitive regions, the majority was located in introns and UTRs. The distributions of A-to-I editing activity and editing depth were analyzed during the course of C. albicans infection. While the normalized editing levels of common editing sites exhibited a significant increase, especially in Alu regions, no significant change in the expression of ADAR1 or ADAR2 was observed. Second, we performed further analysis on data from in vivo mouse study with C. albicans infection. One thousand one hundred thirty three and 955 A-to-I editing sites were identified in mouse tongue and kidney tissues, respectively. The number of A-to-I editing events was much smaller than in human epithelial or endothelial cells, due to the lack of Alu elements in mouse genome. Furthermore, during the course of C. albicans infection we observed stable level of A-to-I editing activity in 131 and 190 common editing sites in the mouse tongue and kidney tissues, and found no significant change in ADAR1 or ADAR2 expression (with the exception of ADAR2 displaying a significant increase at 12 h after infection in mouse kidney tissue before returning to normal).ConclusionsThis work represents the first comprehensive analysis of A-to-I RNA editome in human epithelial and endothelial cells. C. albicans infection of human epithelial and endothelial cells led to the up-regulation of A-to-I editing activities, through a mechanism different from that of viral infections in human hosts. However, the in vivo mouse model with C. albicans infection did not show significant changes in A-to-I editing activities in tongue and kidney tissues. The different results in the mouse model were likely due to the presence of more complex in vivo environments, e.g. circulation and mixed cell types.

Green Tea Polyphenols and Padma Hepaten Inhibit Candida albicans Biofilm Formation.

Candida albicans (C. albicans) is the most prevalent opportunistic human pathogenic fungus and can cause mucosal membrane infections and invade the blood. In the oral cavity, it can ferment dietary sugars, produce organic acids and therefore has a role in caries development. In this study, we examined whether the polyphenol rich extractions Polyphenon from green tea (PPFGT) and Padma Hepaten (PH) can inhibit the caries-inducing properties of C. albicans. Biofilms of C. albicans were grown in the presence of PPFGT and PH. Formation of biofilms was tested spectrophotometrically after crystal violet staining. Exopolysaccharides (EPS) secretion was quantified using confocal scanning laser microscopy (CSLM). Treated C. albicans morphology was demonstrated using scanning electron microscopy (SEM). Expression of virulence-related genes was tested using qRT-PCR. Development of biofilm was also tested on an orthodontic surface (Essix) to assess biofilm inhibition ability on such appliances. Both PPFGT and PH dose-dependently inhibited biofilm formation, with no inhibition on planktonic growth. The strongest inhibition was obtained using the combination of the substances. Crystal violet staining showed a significant reduction of 45% in biofilm formation using a concentration of 2.5mg/ml PPFGT and 0.16mg/ml PH. A concentration of 1.25 mg/ml PPFGT and 0.16 mg/ml PH inhibited candidal growth by 88% and EPS secretion by 74% according to CSLM. A reduction in biofilm formation and in the transition from yeast to hyphal morphotype was observed using SEM. A strong reduction was found in the expression of hwp1, eap1, and als3 virulence associated genes. These results demonstrate the inhibitory effect of natural PPFGT polyphenolic extraction on C. albicans biofilm formation and EPS secretion, alone and together with PH. In an era of increased drug resistance, the use of phytomedicine to constrain biofilm development, without killing host cells, may pave the way to a novel therapeutic concept, especially in children as orthodontic patients.

Analysis of microbiological and physiochemical properties of top soil from municipal dumpsites in Benin City

The effect of disposing municipal waste on soil was evaluated by analyzing the microbiological and enzyme activity of soil samples at three different locations, from five municipal waste dumpsites and compared with soil samples from a farmland which serves as the control. Soil microbial load, physicochemical parameters and enzyme activities were determined using standard procedure. The highest heterotrophic bacterial count (1.02 ± 0.4 × 10 7 cfu/g) was recorded from New Benin market Dumpsite (sampling point A) while the least (3.25 ± 0.4 ×10 4 cfu/g) was from the control (sampling point C). The result obtained showed that there was significant difference (p> 0.05) in the Heterotrophic bacteria and fungi count between the control and the soil samples from the various locations of the dumpsites. The bacteria identified were Acinetobacter species, Micrococcus luetus , Pseudomonas aeruginosa , Serratia species, Bacillus subtilis , Klebsiella species, Staphylococcus aureus , Arthrobacter species, Escherichia coli and Streptococcus feacalis , while fungi identified were Aspergillus niger , Trichoderma species, Penicillium species, Fusarium species, Mucor species, Saccharomyces species, Rhizopus species. Pseudomonas aeruginosa was the most prevalent bacterial isolate (20.3 %) while Streptococcus feacalis was the least isolate (3.1 %). Aspergillus niger was the most prevalent fungi isolate and Fusarium species the least isolated fungi. The enzymatic profile revealed that Oba market and Satana market had the highest Dehydrogenase and Urease activities with the values of 23.70 ± 16.32 mg/g/6h and 97.90 ± 14.93 mg/g/24h respectively. The physicochemical parameter measured in this study showed that the soil samples were acidic (5.60 ± 0.17 – 6.23 ± 0.35) and sandy (72.20 ± 4.11 - 90.60 ± 0.00 %). Trace amount of zinc (0.10 ± 0.00 – 1.53 ± 1.02 mg/kg), lead (< 0.01 – 1.23 ± 0.17 mg/kg) and copper (0.01 ± 0.00 – 0.80 ± 0.10 mg/kg) was observed in both the control soil and the test samples. The result showed that although municipal waste dump is an unsustainable practice, it has a positive impact on the quality of the soil samples examined. Keywords: Microbiological, Enzymatic, Municipal Waste Dumpsites, Soil, Benin City

Molecular typing and genetic relatedness of 72 clinical Candida albicans isolates from poultry

Candida albicans is the most prevalent opportunistic fungus of humans and animals. While most studies focus on human isolates, they rarely focus on poultry isolates. In this study, C. albicans strains were recovered from poultry in the southern Hebei Province (China) and identified. Molecular typing and analyses were performed to understand the molecular epidemiology and genetic relatedness of the strains. The fungi were isolated from live birds with presumed candidiasis or their corpses. The isolates were identified based on morphology, differential medium culture, and rDNA internal transcribed spacer sequencing. The identified C. albicans strains were analyzed by ABC genotyping and multilocus sequence typing. Clonal groups were identified using the eBURST (version 3.0) software, and an UPGMA phylogenetic tree was constructed using the MEGA (version 6.06) software. Overall, 72 isolates were divided into three genotypes (A, B, and C), 48 novel sequence types (STs), five groups with 10 singletons, and four clades. Results indicated that candidiasis is common in poultry in the southern Hebei Province, and that the genetic composition of the C. albicans poultry population from the area is relatively complicated. Based on the eBURST analysis for the STs in this study and others, we suggest that C. albicans poultry isolates were relatively independent but not completely separated from human isolates. The strains with the same or closely related genotypes but recovered from both birds and humans could have transferred and evolved between the two types of host.

Mycological Profile of the Integumentary System in Felin Ponies

Abstract Yeast-like microorganisms are frequently isolated from horses. There is a serious interpretation problem with assessment of the health status in the diagnostics of infectious diseases, which is associated with the insufficient knowledge of the composition of the natural flora in the horses’ integumentary system. The aim of the investigations was to analyse the yeast-like flora isolated from healthy Felin ponies. The study involved 44 horses aged from 2 to 12 years. The analysed group comprised 28 mares and 16 stallions. The animals were kept in an outdoor rearing system with a possibility of periodic use of a wooden/brick shed. The investigations were conducted in an annual cycle divided into 4 periods corresponding to the seasons of the year. Smears were sampled from horses’ nostrils, mouth, ear, back, groin, vagina or foreskin, and collateral groove. Microbiological analysis of the yeast-like strains was performed after plating 1015 samples of material taken from healthy horses. The identification of fungal species was based on their culture characteristics and biochemical profile. Fourteen yeast species were isolated and identified from the sampled material. Candida guilliermondii and Candida albicans 1 were the most prevalent fungi. The study has shown seasonal variability of the composition of the integumentary system microflora in Felin ponies. The greatest number of isolates was obtained from the material sampled from the mouth.

Zombie soldier beetles: Epizootics in the goldenrod soldier beetle, Chauliognathus pensylvanicus (Coleoptera: Cantharidae) caused by Eryniopsis lampyridarum (Entomophthoromycotina: Entomophthoraceae).

Adult goldenrod soldier beetles, Chauliognathus pensylvanicus, were found infected by the fungus Eryniopsis lampyridarum (Entomophthoromycotina) in Arkansas during September - October (1996, 2001, 2015 and 2016). Living and dead infected beetles were found on flowering frost aster, Symphyotrichum pilosum, common boneset, Eupatorium perfoliatum, and Canada goldenrod, Solidago canadensis. Live and dead beetles (n=446) were collected in 1996 from S. pilosum flowers and held individually in the laboratory for determination of fungal prevalence. Of the beetles collected, 281 (63%) were males and 165 (37%) were females. A total of 90 beetles were infected with E. lampyridarum, an overall prevalence of 20.2%. Prevalence in males was 19.6% (n=55 infected/281 males total) and prevalence in females was 21.2% (n=35 infected /165 females total). Conidia were produced from 57% of the infected beetles, 23% of the infected beetles produced resting spores, and 20% contained the hyphal body stage. Infected beetles produced either conidia or resting spores but never both in the same host. Post-mortem morphological changes in the hosts due to E. lampyridarum were observed periodically for 24h. Shortly before death, by unknown mechanisms, dying infected beetles tightly clamped their mandibles into flower heads and ca. 15-22h later (between 2400 and 0700h) the fungus caused dead beetles to raise their elytra and expand their metathoracic wings.

Candida glabrata Biofilms: How Far Have We Come?

Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata’s biofilms are emerging. In this article, the knowledge available on C. glabrata’s resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them.

Antioxidant Bioactive Compounds and Spoilage Microorganisms of Wax Apple (Syzygium samarangense) during Room Temperature Storage

ABSTRACTPostharvest deterioration of wax apple leads to unacceptable appearances, physical and quality losses that raise serious concerns commercially. Bioactive compounds of wax apple and spoilage microorganisms were studied at room temperature storage (23 ± 1 °C). Antioxidant activity and total phenolic content increased up to a maximum of 1.56 mg AAE/100 g and 88.37 mg GAE/100 g, while prolonged storage resulted in 70.0% and 33.6% loss, respectively. Further, 80% loss in vitamin C content was observed from an initial value of 21.63 mg AAE/100 g during storage. Bacterial isolates of Enterobacter sakazakii, Klebsiella pneumoniae, Klebsiella planticola, Pantoea agglomerans, Chromobacterium violaceum, and Streptomyces roseochromogenus with microbial load of 1.19 * 108 CFU/g fresh weight, and fungal isolates of Penicillium purpurogenum, Mucor hiemalis, Aspergillus niger, Aspergillus fumigatus, and Candida tropicalis with a total load of 5.64 * 107 CFU/g fresh weight were identified as spoilage organisms. Bacterial isolates of Klebsiella pneumoniae was the most prevalent at 47.78%, occurring 21 times, while Penicillium purpurogenum was the most prevalent fungi, occurring 5 times at 38.46%. Results have significant implications on measures to preserve quality of wax apples during storage by adoption of advanced postharvest handling and processing approaches.

Fungal biodiversity and mycotoxigenic fungi in cooling-tower water systems in Istanbul, Turkey.

This is the first study to assess fungal diversity and mycotoxigenic fungi in open recirculating cooling-tower (CT) water systems (biofilm and water phase). The production capability of mycotoxin from fungal isolates was also examined. The mean fungal count in 21 different water and biofilm samples was determined as 234 CFU/100 mL and 4 CFU/cm2. A total of 32 species were identified by internal transcribed spacer (ITS) sequencing. The most common isolated fungi belonged to the genera Aspergillus and Penicillium, of which the most prevalent fungi were Aspergillus versicolor, Aspergillus niger, and Penicillium dipodomyicola. From 42% of the surveyed CTs, aflatoxigenic A. flavus isolates were identified. The detection of opportunistic pathogens and/or allergen species suggests that open recirculating CTs are a possible source of fungal infection for both the public and for occupational workers via the inhalation of aerosols and/or skin contact.

Assessment of occupational exposure to azole resistant fungi in 10 Portuguese bakeries.

Occupational exposure to bioaerosols resulting from handling of flour dust and raw materials in bakeries is associated with health problems. The emergence of azole-resistant fungal species in the environment is thought to be related with the use of azole fungicides in cereal crops and prevention of postharvest spoilage. As raw materials used in bakeries are commonly exposed to azoles, we investigated the mycobiota and azole-resistant fungi prevalence in this occupational environment. Ten Portuguese bakeries were assessed through electrostatic dust cloth (EDC, n = 27), settled dust (n = 7), and raw material (n = 26) samples. Samples were inoculated in malt extract agar (2%) (MEA) with chloramphenicol (0.05 g/L) and in dichloran glycerol (DG18), and onto Saboraud screening media supplemented with 4 mg/L itraconazole, 1 mg/L voriconazole, or 0.5 mg/L posaconazole, and incubated for 3–5 days at 27 °C. Except for one out of the ten analyzed bakeries, Cladosporium sp., Penicillium sp., and Aspergillus sp. were the most prevalent fungi identified. Aspergillus sp. and Mucorales order were identified in raw materials with both media, whereas Penicillium sp. was identified in DG18 only. Azole-resistant species were identified in the environment (EDC) and, to a lower extent, in raw materials, including Aspergillus sp. and Mucorales. The presence of azole-resistant fungal species in bakeries represents an occupational risk for workers. This study proposes complementary sampling methods for the evaluation of occupational exposure to mycobiota, and highlights the importance of studying the prevalence of azole-resistant strains in specific occupational environments.

The mycobiome of root canal infections is correlated to the bacteriome

ObjectivesBacterial infection of the root canal system causes apical periodontitis. Less is known about the role of fungi in these infections. This study aimed to assess the fungal prevalence, abundance, and diversity of root canal infections, as well as the relation between fungi and bacteria present in different parts of the root canal.Materials and methodsTwenty-six teeth with primary apical periodontitis were extracted, split in apical and coronal root segments, and cryo-pulverized. Bacteriome profiles of 23 teeth were analyzed based on the V3-V4 hypervariable region of the 16S ribosomal RNA gene. Mycobiome profiles of six teeth were analyzed based on the internal transcribed spacer (ITS) 1 or ITS2 region. Samples were sequenced on the Illumina MiSeq platform.ResultsA total of 338 bacterial operational taxonomic units (OTUs), 28 ITS1 OTUs, and 24 ITS2 OTUs were identified. Candida and Malassezia were the most frequently identified fungi. No differences could be found between the bacteriome and mycobiome profiles of the apical and coronal root segments. The bacteriome of fungi-positive root segments contained more Actinomyces, Bifidobacterium, four different Lactobacillus OTUs, Propionibacterium, and Streptococcus. A Spearman correlation matrix between bacteriomes and mycobiomes identified no correlations, but separate clusters could be observed.ConclusionsA considerable proportion of the root canal infections contain fungi, although fungal diversity is limited. However, when fungi are present, the composition of the bacteriome is clearly different.Clinical relevanceInteraction between bacteria and fungi in root canal infections may complicate the infection and require alternative treatment strategies.

Change in soil fungal community structure driven by a decline in ectomycorrhizal fungi following a mountain pine beetle (Dendroctonus ponderosae) outbreak.

Western North American landscapes are rapidly being transformed by forest die-off caused by mountain pine beetle (Dendroctonus ponderosae), with implications for plant and soil communities. The mechanisms that drive changes in soil community structure, particularly for the highly prevalent ectomycorrhizal fungi in pine forests, are complex and intertwined. Critical to enhancing understanding will be disentangling the relative importance of host tree mortality from changes in soil chemistry following tree death. Here, we used a recent bark beetle outbreak in lodgepole pine (Pinus contorta) forests of western Canada to test whether the effects of tree mortality altered the richness and composition of belowground fungal communities, including ectomycorrhizal and saprotrophic fungi. We also determined the effects of environmental factors (i.e. soil nutrients, moisture, and phenolics) and geographical distance, both of which can influence the richness and composition of soil fungi. The richness of both groups of soil fungi declined and the overall composition was altered by beetle-induced tree mortality. Soil nutrients, soil phenolics and geographical distance influenced the community structure of soil fungi; however, the relative importance of these factors differed between ectomycorrhizal and saprotrophic fungi. The independent effects of tree mortality, soil phenolics and geographical distance influenced the community composition of ectomycorrhizal fungi, while the community composition of saprotrophic fungi was weakly but significantly correlated with the geographical distance of plots. Taken together, our results indicate that both deterministic and stochastic processes structure soil fungal communities following landscape-scale insect outbreaks and reflect the independent roles tree mortality, soil chemistry and geographical distance play in regulating the community composition of soil fungi.