Pharmacodynamics of Posaconazole in Experimental Invasive Pulmonary Aspergillosis: Utility of Serum Galactomannan as a Dynamic Endpoint of Antifungal Efficacy

Background. Aspergillus galactomannan antigenemia is an accepted tool for the diagnosis of invasive pulmonary aspergillosis (IPA) in neutropenic patients. Little is known, however, about the utility of this biomarker to assess the efficacy of antifungal therapies. Methods. The pharmacokinetics and pharmacodynamics (PK/PD) of posaconazole in treatment and prophylaxis were investigated in the persistently neutropenic rabbit model of Aspergillus fumigatus IPA at doses between 2 and 20 mg/kg and day. Sparse plasma sampling was used to obtain PK data at steady state, and the serum galactomannan index (GMI), as a dynamic endpoint of antifungal response, was obtained every other day in addition to conventional outcome parameters including survival and fungal tissue burden. Nonparametric PK/PD model building was performed using the Pmetrics Package in R. Results. A one-compartment model with linear elimination best described the PK of posaconazole. The PD effect of posaconazole exposure in plasma on the GMI in serum was best described by a dynamic Hill-functions reflecting growth and kill of the fungus. Through calculations of the AUC0-24h at steady state, the exposure-response relationship between posaconazole and the GMI for treatment followed a sigmoidal function with an asymptote forming above an AUC0-24h of 30 mg*h/L. All prophylactic doses were able to control the fungal burden. Conclusions. A nonparametric population PK/PD model adequately described the effect of posaconazole in prophylaxis and treatment of experimental IPA. An AUC0-24h greater than 30 mg*h/L was associated with adequate resolution of the GMI, which is well in support of previously suggested exposure-response relationships in humans.

739. A Two-Center Assessment of Histopathologic Diagnostic Performance for Fungal Organism Identification

Background Accurate detection and identification of invasive fungal pathogens relies on concordance of several complementary laboratory techniques, including fungal culture, serology, and histopathologic identification. Histopathologic stains such as the Gomori methenamine silver stain (GMS) are used to highlight fungal cell wall in tissue specimens. We sought to determine the diagnostic performance of histopathology fungal stains as compared to fungal culture for diagnosis of invasive fungal tissue infection at tertiary medical centers with dissimilar patient populations. Methods We performed a retrospective review of all surgical pathology specimens with reported GMS results and concurrent fungal culture at Keck Medical Center (Keck) and Los Angeles County + USC Medical Center (LAC). Ratios of GMS diagnostic performance were compared using chi-squared analyses, with fungal culture as the gold standard for detection. Results Of 1347 LAC surgical pathology specimens stained with GMS to evaluate for fungal infection, 229 (17.0%) had concurrent tissue specimens submitted for fungal culture. Of 1546 Keck GMS-stained surgical pathology specimens, 358 (23.2%) had concurrent tissue for fungal culture. GMS stain performance at LAC showed a sensitivity of 53.7% (95% CI: 37.4-69.3%) and specificity of 90.4% (95% CI: 85.2-94.2%). At Keck, GMS showed a sensitivity of 64.1% (95% CI: 52.4-74.7%), specificity of 88.9% (95% CI: 84.7-92.4%), without significant difference in performance between sites, (p=0.27) and (p=0.62), respectively. Among filamentous fungi, GMS false negative frequency at LAC was 5.3% (10/190) and 4.0% (11/277) at Keck, without significant difference (p=0.51). A subset of pathology reports suggested the fungus genus based on histologic morphology. Of 10 LAC pathology specimens with fungal genus specified, 2 (20.0%) reports gave the incorrect genus and 8/18 (44.4%) reports at Keck gave incorrect genus as per concurrent culture isolate result. Table 1. Diagnostic performance of GMS histopathology stain on surgical pathology specimens compared to tissue fungal culture at LAC and Keck Medical Centers from July 2015 through December 2018. Conclusion GMS stain had low-to-moderate sensitivity when compared to fungal tissue culture. Increased submission of concurrent tissue for fungal culture is likely to improve detection. When genus level identification was attempted, fungal forms were incorrectly identified in about one-third of histopathology specimens. Disclosures All Authors: No reported disclosures

The microbiome profiling of fungivorous black tinder fungus beetleBolitophagus reticulatusreveals the insight into bacterial communities associated with larvae and adults

Saproxylic beetles play a crucial role in key processes occurring in forest ecosystems, and together with fungi contribute to the decomposition and mineralization of wood. Among this group are mycetophilic beetles which associate with wood-decaying fungi and use the fruiting body for nourishment and development. Therefore, their feeding strategy (especially in the case of fungivorous species) requires special digestive capabilities to take advantage of the nutritional value of fungal tissue. Although polypore-beetle associations have been investigated in numerous studies, detailed studies focusing on the microbiome associated with species feeding on fruiting bodies of polypores remain limited. Here we investigated the bacterial communities associated with larvae and adults ofBolitophagus reticulatuscollected fromFomes fomentariusgrowing on two different host tree: beech (Fagussp.) and birch (Betulasp.), respectively. Among 24 identified bacterial phyla, three were the most relatively abundant (Proteobacteria, Actinobacteria and Bacteroidetes). Moreover, we tried to find unique patterns of bacteria abundances which could be correlated with the long-term field observation showing that the fruiting bodies ofF. fomentarius,growing on birch are more inhabited by beetles than fruiting bodies of the same fungus species growing on beech. Biochemical analyses showed that the level of protease inhibitors and secondary metabolites inF. fomentariusis higher in healthy fruiting bodies than in the inhabited ones. However, tested microbiome samples primarily clustered by developmental stage ofB. reticulatusand host tree did not appear to impact the taxonomic distribution of the communities. This observation was supported by statistical analyses.

Phylogenetic Analysis of Polyporous Fungi Collected from Batam Botanical Garden, Riau Province, Indonesia

Botanical gardens are areas that provide protection for trees and other organisms like polyporous fungi. Polyporous fungi are important fungi that degrade remaining lignocellulosic in leaf litter or dead trees. These mycobiota are also noted for their vital role in biorefinery, bioremediation, medicine and phytopathogen. The knowledge of the importance of the polyporous fungi to describe polyporous fungal species is fundamental for generating data base information of their occurrence and their functions. This research’s goal was to explore and characterize the polyporous fungi collected in Batam Botanical Garden in three sampling areas. Fungal samples were collected in May and July 2017. Subsequently, morphological characters were recorded, the fungal tissue was isolated to extract the DNA, then the data sequence was amplified and aligned to construct a phylogenetic tree. Five fungal families found belong to order Polyporales and were classified morphologically. They were Polyporaceae, Ganodermataceae, Fomitopsidaceae, Irpicaceae and Hymenochaetaceae. Three fungal species namely; Pycnoporus sanguineus, Trametes ijubarskii, and Antrodia wangii were identified based on phyllogenetic analysis whereas seven other fungal samples were identified as Earliella scabrosa, Hexagonia tenuis, Polyporus tenuiculus Lenzites betulina, Lentinus concavus, Phellinus rimosus and Hexagonia apiaria. This study classifies and adds fundamental databases on fungal taxonomy and diversity on the fungal organisms found in Batam Botanical Garden. This background data is vital to carry out an advance research in some areas such as bio-chemistry, bio-degradation, pharmacology and biotechnology.

Structure of foliicolous thalli of the Gomphillaceae in a south-western Florida lichen community

Foliicolous lichens complete their life cycles upon non-deciduous leaves in humid tropical and subtropical environments. The anatomy of these lichens and its adaptations to this specialized niche have received only limited attention. The present work examines the structural organization in seven species of the Gomphillaceae that colonize palm leaves in south-west Florida, USA. Thalli with their leaf substratum were embedded in resin and examined with SEM in backscattered electron detection mode. All species showed a continuous, covering epilayer of fungal origin that consisted of relatively sparse, scattered cell lumina of reduced diameter connected by cell wall-derived material. Fungal cells were intermixed below this layer, with algal cells often resting directly on the substratum. Interactions between symbionts were mainly limited to wall-to-wall contacts without penetration. The epilayer showed continuity with the fungal prothallus at the perimeter of the thalli. Crystalline deposits in the upper portions of thalli were common, particularly in the species of Gyalectidium examined. All thalli were entirely epicuticular; some covered the stomata of the leaf beneath. It is suggested that the prominence of non-living wall materials and mineral crystals in thallus structure might serve to minimize the metabolic cost of fungal tissue in climates where warm temperatures at night result in higher rates of respiration.

Biology and evolution of the Epichloë-associated Botanophila species found in Europe (Diptera: Anthomyiidae)

The anthomyiid genus Botanophila consists of over 200, mostly phytophagous, species. One species group maintains a mutualistic relationship with Epichloë fungi, thereby acting as vector of fungal spermatia required for fertilization, similar to pollinating parasites. The phylogenetic relationship of these flies with other Botanophila and the related Chiastocheta species (obligatory associated with globeflowers) remains largely unresolved. In this study, we obtained new sequences of the mitochondrial genes COI and COII from a representative sample of 17 European Botanophila and Chiastocheta species including all six Epichloë-associated species, as well as from four outgroup taxa. Phylogenetic analyses indicated that Epichloë-associated Botanophila form a distinct clade suggesting that ancestral Botanophila may have expanded its niche to European fungal hosts once and then successfully radiated while exploiting fungal tissue as additional food source. Furthermore, the three included Chiastocheta species formed a distinct clade nested within Botanophila, leaving the genus paraphyletic as currently circumscribed.