Fungal Infections and Colonization after Bilateral Lung Transplant: A Six-Year Single-Center Experience

Fungal infections (FIs) are one of the leading causes of morbidity and mortality within the first year of lung transplant (LT) in LT recipients (LTRs). Their prompt identification and treatment are crucial for a favorable LTR outcome. The objectives of our study were to assess (i) the FI incidence and colonization during the first year after a bilateral LT, (ii) the risk factors associated with FI and colonization, and (iii) the differences in fungal incidence according to the different prophylactic strategies. All bilateral LTRs admitted to the intensive care unit of Padua University Hospital were retrospectively screened, excluding patients <18 years of age, those who had been re-transplanted, and those who had received ventilation and/or extracorporeal membrane oxygenation before LT. Overall, 157 patients were included. A total of 13 (8%) patients developed FI, and 36 (23%) developed colonization, which was mostly due to Aspergillus spp. We did not identify independent risk factors for FI. Groups of patients receiving different prophylactic strategies reported a similar incidence of both FI and colonization. The incidence of FI and fungal colonization was 8% and 23%, respectively, with no differences between different antifungal prophylaxes or identified predisposing factors. Further studies with larger numbers are needed to confirm our results.

Bile Acid Regulates Mononuclear Phagocytes and T Helper 17 Cells to Control Candida albicans in the Intestine

Invasive Candida albicans (CA) infections often arise from the intestine and cause life-threatening infections in immunocompromised individuals. The role of gut commensal microbiota, metabolites, and host factors in the regulation of CA colonization in the intestine is poorly understood. Previous findings from our lab indicate that taurocholic acid (TCA), a major bile acid present in the intestine, promotes CA colonization and dissemination. Here, we report that oral administration of TCA to CA-infected mice significantly decreased the number of mononuclear phagocytes and CD4+ IL17A+ T helper 17 cells that play a critical role in controlling CA in the intestine. Collectively, our results indicate that TCA modulates mucosal innate and adaptive immune responses to promote CA colonization in the intestine.

Methyl Potassium Siliconate and Siloxane Inhibit the Formation of Multispecies Biofilms on Ceramic Roof Tiles: Efficiency and Comparison of Two Common Water Repellents

Ceramic roof tiles are widespread marketed building materials, rapidly colonized by microorganisms that form multispecies biofilms on their surface and play crucial roles in biodeterioration processes. Coating tiles with water repellents is a pervasive industrial strategy employed to prevent liquid water penetration and slow biodeterioration. Very few studies have examined the links between the characteristics of water-repellent coatings and biofilm colonization patterns. Our work aims to compare the effects of coating tiles with two common water repellents (siliconate and siloxane) on the growth of colonizing microbes. We combined in situ exposure of tiles for over six years and macroscopic and microscopic observations with in vitro biotests, relying on the use of algal and fungal models. Our data showed that (1) tiles coated with water repellents were macroscopically less colonized by lichens (2) a significant fungal biofilm development at the microscopic scale (3) water repellents had very contrasting effects on our model strains. These data reinforce the great interest for industry to conduct more studies linking the nature of the water repellents with the composition of colonizing multispecies biofilms. The long-term objective is to improve the available water repellents and better adapt their selection to the nature of microbial colonization.

In vivo infection of Bursaphelenchus xylophilus by the fungus Esteya vermicola

BACKGROUND

As the causal agent of pine wilt disease, Bursaphelenchus xylophilus, is a serious pathogen of forest pine trees. Esteya vermicola is a nematophagous fungus of B. xylophilus and exhibits great potential as a biological control agent. However, the in vivo infection mechanism of E. vermicola on B. xylophilus is unclear. Experiments were conducted to study the colonization of host plant and infection of B. xylophilus by E. vermicola inside pine tree xylem.

RESULTS

A green fluorescent protein (GFP)-tagged E. vermicola transformant was constructed as a biomarker to study the in vivo colonization and infection of B. xylophilus in pine trees. The in vitro infection of B. xylophilus by E. vermicola was observed through GFP expression. The bacilloid conidia produced by trophic hyphae in the body of the nematode are described. Additionally, the monitoring of in vivo colonization by GFP-tagged E. vermicola showed the germination and hyphal extension of this fungus after inoculation. Moreover, B. xylophilus infected by this biocontrol agent were extracted from healthy seedlings and observed in the xylem of trees that were wilting due to pine wilt disease.

CONCLUSION

Evidence of fungal colonization and infection of B. xylophilus by E. vermicola is provided to improve our understanding of the in vivo infection mechanisms used by this nematophagous fungus against B. xylophilus. The infection of B. xylophilus by E. vermicola was inferred to begin with the implantation of propagules, and this inference will require future investigation. The colonization of Esteya vermicola in host pine tree xylem and the in vivo infection of pinewood nematode by E. vermicola were investigated using the green fluorescence protein transformant. © 2020 Society of Chemical Industry.

Prevalence of Dermatitis and Superficial Fungal Infection of the Hands in Seafood Workers: An Investigation from Food Markets in Ningbo, China

Objective

Seafood workers have high risks of hand skin diseases. The purpose of this survey is to study the prevalence of occupational hand skin diseases in this population.

Methods

From March 2018 to October 2018, seafood workers in two food markets in Ningbo, China were investigated. Fungal microscopy and cultures from lesions on the hands and nails were performed. A community-based investigation of hand skin diseases was performed as a control group.

Results

One handred and eleven of 135 (82.2%) seafood workers in two food markets in Ningbo were taken into the investigation. The prevalence of hand dermatitis was 50.5% (56/111) in seafood workers, which is significantly higher than that of the control group (7.43%, p<0.001). It was found that the incidence of superficial fungal infection of the hands in seafood workers was much higher than that in community residents (26.1% vs 2.7%, p<0.001). Without wearing waterproof gloves, longer working time per day, longer history of seafood work increased the risk of hand dermatitis, instead of candidial infection of the hands and nails.

Conclusion

Hand skin diseases are highly prevalent in seafood workers in Ningbo, a city in eastern China. This public health problem should be addressed in this population.

Related mobile pathogenicity chromosomes in Fusarium oxysporum determine host range on cucurbits

Fusarium oxysporum f. sp. radicis-cucumerinum (Forc) causes severe root rot and wilt in several cucurbit species, including cucumber, melon, and watermelon. Previously, a pathogenicity chromosome, chr^RC , was identified in Forc. Strains that were previously nonpathogenic could infect multiple cucurbit species after obtaining this chromosome via horizontal chromosome transfer (HCT). In contrast, F. oxysporum f. sp. melonis (Fom) can only cause disease on melon plants, even though Fom contains contigs that are largely syntenic with chr^RC . The aim of this study was to identify the genetic basis underlying the difference in host range between Fom and Forc. First, colonization of different cucurbit species between Forc and Fom strains showed that although Fom did not reach the upper part of cucumber or watermelon plants, it did enter the root xylem. Second, to select candidate genomic regions associated with differences in host range, high-quality genome assemblies of Fom001, Fom005, and Forc016 were compared. One of the Fom contigs that is largely syntenic and highly similar in sequence to chr^RC contains the effector gene SIX6. After HCT of the SIX6-containing chromosome from Fom strains to a nonpathogenic strain, the recipient (HCT) strains caused disease on melon plants, but not on cucumber or watermelon plants. These results provide strong evidence that the differences in host range between Fom and Forc are caused by differences between transferred chromosomes of Fom and chr^RC , thus narrowing down the search for genes allowing or preventing infection of cucumber and watermelon to genes located on these chromosomes.

Fungal Endophyte Colonization Patterns Alter Over Time in the Novel Association Between Lolium perenne and Epichloë Endophyte AR37

Infection of the pasture grass Lolium perenne with the seed-transmitted fungal endophyte Epichloë festucae enhances its resilience to biotic and abiotic stress. Agricultural benefits of endophyte infection can be increased by generating novel symbiotic associations through inoculating L. perenne with selected Epichloë strains. Natural symbioses have coevolved over long periods. Thus, artificial symbioses will probably not have static properties, but symbionts will coadapt over time improving the fitness of the association. Here we report for the first time on temporal changes in a novel association of Epichloë strain AR37 and the L. perenne cultivar Grasslands Samson. Over nine generations, a seed maintenance program had increased the endophyte seed transmission rates to > 95% (from an initial 76%). We observed an approximately fivefold decline in endophyte biomass concentration in vegetative tissues over time (between generations 2 and 9). This indicates strong selection pressure toward reducing endophyte-related fitness costs by reducing endophyte biomass, without compromising the frequency of endophyte transmission to seed. We observed no obvious changes in tillering and only minor transcriptomic changes in infected plants over time. Functional analysis of 40 plant genes, showing continuously decreasing expression over time, suggests that adaptation of host metabolism and defense mechanisms are important for increasing the fitness of this association, and possibly fitness of such symbioses in general. Our results indicate that fitness of novel associations is likely to improve over time and that monitoring changes in novel associations can assist in identifying key features of endophyte-mediated enhancement of host fitness.

Detection and treatment of Candida auris in an outbreak situation: risk factors for developing colonization and candidemia by this new species in critically ill patients

BACKGROUND

Candida auris is an emerging, multidrug-resistant yeast causing hospital outbreaks. This study describes the first 24 months of the ongoing C. auris outbreak in our hospital and analyzes predisposing factors to C. auris candidemia/colonization.

RESEARCH DESIGN AND METHODS

A 12-month prospective, case-controlled study was performed including a total of 228 patients (114 colonized/candidemia and 114 controls). Data from the first 79 candidemia episodes and 738 environmental samples were also analyzed. Definitive C. auris identification was performed by ITS sequencing. Antifungal susceptibility was carried out by EUCAST methodology.

RESULTS

Polytrauma (32%), cardiovascular disease (25%), and cancer (17%) were the most common underlying condition in colonized/candidemia patients. Indwelling CVC (odds ratio {OR}, 13.48), parenteral nutrition (OR, 3.49), and mechanical ventilation (OR, 2.43) remained significant predictors of C. auris colonization/candidemia. C. auris was most often isolated on sphygmomanometer cuffs (25%) patient tables (10.2%), keyboards (10.2%), and infusion pumps (8.2%). All isolates were fully resistant to fluconazole (MICs >64 mg/L) and had significantly reduced susceptibility to voriconazole (GM, 1.8 mg/L).

CONCLUSIONS

Predictor conditions to C. auris colonization/candidemia are similar to other Candida species. C. auris colonizes multiple patient's environment surfaces. All isolates are resistant to fluconazole and had significant reduced susceptibility to voriconazole.

Risk and outcomes of pulmonary fungal infection after pediatric lung transplantation

BACKGROUND

Prospective studies to determine associated risk factors and related outcomes for pulmonary fungal infection (PFI) after pediatric lung transplant (PLT) are lacking.

METHODS

NIH-sponsored Clinical Trials in Organ Transplantation in Children enrolled PLT candidates, collecting data prospectively for 2 years post-transplant. Demographics, signs/symptoms, radiology, pathology and microbiology were collected. Analyses evaluated for PFI-related risks and outcomes.

RESULTS

In 59 PLT, pre-transplant fungal colonization occurred in 6 donors and 15 recipients. Cystic fibrosis (CF) was associated with pre-transplant colonization (P < .01). Twenty-five (42%) PLT had 26 post-transplant colonizations (median = 67 days, range = 0-750 days) with Candida (13), Aspergillus (4), mold (6) or yeast (3). Post-PLT colonization was not associated with CF, age, or pre-PLT colonization. Thirteen PFIs occurred in 10 (17%) patients, 3 proven (Candida species) and 10 probable (Candida [3], Aspergillus [3], Penicillium [3], and mold [1]). Pulmonary fungal infection was preceded by post-PLT colonization with the same organism in 4 of 13 PFI, but post-PLT colonization did not predict subsequent PFI (P = .87). Older age at transplant was a risk for PFI (P < .01). No mortality was attributed to PFI. Prophylaxis use was not associated with decreased post-PLT colonization (P = .60) or PFI (P = .48).

CONCLUSION

In PLT, PFI and fungal colonization are common but without associated mortality. Post-PLT colonization did not predict PFI. Optimal prevention strategies require additional study.

Immunosuppression, peripheral inflammation and invasive infection from endogenous gut microbiota activate retinal microglia in mouse models

Although its actual role in the progression of degenerative processes is not fully known, the persistent activated state of retinal microglia and the concurrent secretion of inflammatory mediators may contribute to neuronal death and permanent vision loss. Our objective was to determine whether non-ocular conditions (immunosuppression and peripheral inflammation) could lead to activation of retinal microglia. Mouse models of immunosuppression induced by cyclophosphamide and/or peripheral inflammation by chemically induced sublethal colitis in C57BL/6J mice were used. Retinal microglia morphology, spatial distribution and complexity, as well as MHCII and CD11b expression levels were determined by flow cytometry and confocal immunofluorescence analysis with anti-CD11b, anti-IBA1 and anti-MHCIIRT1B antibodies. Retinas of mice with double treatment showed changes in microglial morphology, spatial distribution and expression levels of CD11b and MHCII. These effects were higher than those observed with any treatment separately. In addition, we also observed in these mice: (i) translocation of endogenous bacteria from gut to liver, and (ii) upregulation of TLR2 expression in retinal microglia. Using a mouse model of immunosuppression and gut colonization by Candida albicans, translocation of fungal cells was confirmed to occur in wild type and, to a higher extent, in TLR2 KO mice, which are more susceptible to fungal invasion; interestingly microglial changes were also higher in TLR2 KO mice. Hence, non-ocular injuries (immunosuppression, peripheral inflammation and invasive infection from endogenous gut microbiota) can activate retinal microglia and therefore could affect the progression of neurodegenerative disorders and should be taken into account to improve therapeutic options.

(1→3)-β-d-Glucan and Galactomannan for Differentiating Chemical "Black Particles" and Fungal Particles Inside Peritoneal Dialysis Tubing

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BACKGROUND

Aseptic, sheet-like foreign bodies observed inside Tenckhoff (TK) catheter lumens (referred to as "black particles") are, on gross morphology, hardly distinguishable from fungal colonization because these contaminants adhere tightly to the catheter. Detection of fungal cell wall components using (1→3)-β-d-glucan (BG) and galactomannan index (GMI) might be an alternative method for differentiating the particles. ♦

METHODS

Foreign particles retrieved from TK catheters in 19 peritoneal dialysis patients were examined microscopically and cultured for fungi and bacteria. Simultaneously, a Fungitell test (Associates of Cape Cod, Falmouth, MA, USA) and a Platelia Aspergillus ELISA assay (Bio-Rad Laboratories, Marnes-La-Coquette, France) were used to test the spent dialysate for BG and GMI respectively. ♦

RESULTS

Of the 19 patients, 9 had aseptic black particles and 10 had fungal particles in their tubing. The fungal particles looked grainy, were tightly bound to the catheter, and appeared more "colorful" than the black particles, which looked sheet-like and could easily be removed by milking the tubing. Compared with effluent from patients having aseptic particles, effluent from patients with fungal particles had significantly higher levels of BG (501 ± 70 pg/mL vs. 46 ± 10 pg/mL) and GMI (10.98 ± 2.17 vs. 0.25 ± 0.05). Most of the fungi that formed colonies inside the catheter lumen were molds not usually found in clinical practice, but likely from water or soil, suggesting environmental contamination. Interestingly, in all 10 patients with fungal colonization, visualization of black particles preceded a peritonitis episode and TK catheter removal by approximately 1-3 weeks; in patients with aseptic particles, a 17-week onset to peritonitis was observed. ♦

CONCLUSIONS

In all patients with particle-coated peritoneal dialysis tubing, spent dialysate should be screened for BG and GMI. Manipulation of the TK catheter by squeezing, hard flushing, or even brushing to dislodge black particles should be avoided. Replacement of the TK catheter should be suspended until a cause for the particles is determined.

Yield of fungal surveillance cultures in pediatric hematopoietic stem cell transplant patients: a retrospective analysis and survey of current practice

BACKGROUND

Fungal surveillance cultures (FSCs) have been proposed as predictors for development of invasive fungal disease (IFD) and identifiers of the causative organism, although data supporting these are limited and predate universal initiation of antifungal prophylaxis. We aimed to define the epidemiology of fungal colonization and investigate the utility of FSCs for predicting IFD in recipients of pediatric hematopoietic stem cell transplantation (HSCT).

METHODS

FSCs performed from 2007 to 2011 on HSCT patients and laboratory and clinical data were reviewed, and incidence of IFD was determined. Descriptive analyses of culture results were performed to determine the yield of FSCs and their utility. A Web-based survey of national pediatric HSCT providers was undertaken to evaluate current practice and the relevance of our results.

RESULTS

Five thousand six hundred eighteen FSCs from nares, throat, and stool from 360 patients were processed. Of these, 14.8% were positive: 30.3% from stool, 13.2% from throat, and 0.9% from nares; 64.4% of patients had >1 positive FSCs. Thirty (8.3%) patients had IFD. IFD occurred in 7.9% and 10.1% of patients with positive and negative FSCs, respectively (P = .25). Antifungal coverage was changed in 69 patients (29.9%) after positive FSC; 8.6% developed IFD (n = 2 of 6 pathogen concordance with FSC) compared with 6.7% (P = .59) who had no treatment change (n = 3 of 11 concordance). The response rate to the survey was 70.8%; 40% of institutions reported performing routine FSC. Twenty-five percent of providers would not change management based on FSC results; overall rating of usefulness of FSCs was low.

CONCLUSIONS

Although FSCs are commonly performed for pediatric HSCT patients, they have limited utility for predicting IFD.

INTERNAL SPREAD OF FUNGI INOCULATED

The white-rotting basidiomycetes Exidia glandulosa, Peniophora quercina, Phellinus ferreus, Schizopora paradoxa, Stereum gausapatum and Vuilleminia comedenswere inoculated into attached living branches of oak (Quercus robur). Patterns of establishment and spread varied in relation to species, time of inoculation and location with respect to branch order and proximity of experimental girdles. Peniophora quercina, Stereum gausapatum and V. comedens readily formed localized decay columns within 6 months, but apparently failed to extend further subsequently. The other fungi either failed to establish, or spread only for limited distances, E. glandulosa preferentially colonizing bark. Longitudinal spread was often markedly facilitated within the vicinity of a girdle, although radial and tangential spread were restricted. In several instances, individuals of Peniophora quercina, Stereum gausapatum and V. comedens became established naturally within the branches. Such individuals were invariably somatically incompatible with those inoculated, and further contrasted with the latter in giving rise to columns of considerable longitudinal and radial extent.