Biology and biotechnology of Trichoderma

Fungi of the genus Trichoderma are soilborne, green-spored ascomycetes that can be found all over the world. They have been studied with respect to various characteristics and applications and are known as successful colonizers of their habitats, efficiently fighting their competitors. Once established, they launch their potent degradative machinery for decomposition of the often heterogeneous substrate at hand. Therefore, distribution and phylogeny, defense mechanisms, beneficial as well as deleterious interaction with hosts, enzyme production and secretion, sexual development, and response to environmental conditions such as nutrients and light have been studied in great detail with many species of this genus, thus rendering Trichoderma one of the best studied fungi with the genome of three species currently available. Efficient biocontrol strains of the genus are being developed as promising biological fungicides, and their weaponry for this function also includes secondary metabolites with potential applications as novel antibiotics. The cellulases produced by Trichoderma reesei, the biotechnological workhorse of the genus, are important industrial products, especially with respect to production of second generation biofuels from cellulosic waste. Genetic engineering not only led to significant improvements in industrial processes but also to intriguing insights into the biology of these fungi and is now complemented by the availability of a sexual cycle in T. reesei/Hypocrea jecorina, which significantly facilitates both industrial and basic research. This review aims to give a broad overview on the qualities and versatility of the best studied Trichoderma species and to highlight intriguing findings as well as promising applications

Comparison of aerobic standard medium with specific fungal medium for detecting Fusarium spp. in blood cultures

International audienceIn order to compare the performances of a specific fungal medium and a standard aerobic medium for detecting growth of Fusarium spp. in blood, simulated blood cultures were performed. For lower inocula (10(2) and 10(3) cfu/ml taken together), fungal growth was detected significantly earlier using the fungal medium. The mean difference in the time to detection between the two media was 22.33 h at 10(2) cfu/ml, with the maximum difference being achieved for Fusarium verticilloides at 37.05 h. These in vitro test results suggest fungal medium could be useful for obtaining more rapid blood culture results when evaluating patients at risk for invasive infection with Fusarium spp

Severe neurological disorders and refractory aspergillosis in an adolescent treated by vincristine and voriconazole

International audienceWhat is known and objectiveVoriconazole and vincristine are major therapeutics in paediatric haematology. However, the risk-benefit ratio of the treatment of invasive aspergillosis with voriconazole in patients receiving vincristine-based chemotherapy remains unclear. Case descriptionWe report severe peripheral and central neurological disorders in a 14-year-old girl with T-cell acute lymphoblastic leukaemia and pulmonary aspergillosis. The case describes a strong exacerbation by voriconazole of the vincristine-induced neuropathic pains. It shows the high variability of the trough serum concentration of voriconazole leading to antifungal treatment failure and suggests that its own central neurotoxicity could also be potentiated by vincristine. What is new and conclusionGiven the risk of either insufficient antifungal efficacy or excessive neurological disorders, this case warns on a probable unfavourable risk-benefit profile of voriconazole during vincristine-based chemotherapy in adolescents

Détection of mucorales DNA in serum: retrospective analysis of 44 mucormycoses collected through the French Surveillance Network of Invasive Fungal Infections (RESSIF)

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Early diagnosis and monitoring of mucormycosis by detection of circulating DNA in serum: retrospective analysis of 44 cases collected through the French Surveillance Network of Invasive Fungal Infections (RESSIF)

International audienceThe main objective of this study was to assess the diagnostic performance of a set of three Mucorales quantitative PCR assays in a retrospective multicentre study. Mucormycosis cases were recorded thanks to the French prospective surveillance programme (RESSIF network). The day of sampling of the first histological or mycological positive specimen was defined as day 0 (D0). Detection of circulating DNA was performed on frozen serum samples collected from D-30 to D30, using quantitative PCR assays targeting Rhizomucor, Lichtheimia, Mucor/Rhizopus. Forty-four patients diagnosed with probable (n = 19) or proven (n = 25) mucormycosis were included. Thirty-six of the 44 patients (81%) had at least one PCR-positive serum. The first PCR-positive sample was observed 9 days (range 0-28 days) before diagnosis was made using mycological criteria and at least 2 days (range 0-24 days) before imaging. The identifications provided with the quantitative PCR assays were all concordant with culture and/or PCR-based identification of the causal species. Survival rate at D84 was significantly higher for patients with an initially positive PCR that became negative after treatment initiation than for patients whose PCR remained positive (48% and 4%, respectively; p \textless10(-6)). The median time for complete negativity of PCR was 7 days (range 3-19 days) after initiation of l-AmB treatment. Despite some limitations due to the retrospective design of the study, we showed that Mucorales quantitative PCR could not only confirm the mucormycosis diagnosis when other mycological arguments were present but could also anticipate this diagnosis. Quantification of DNA loads may also be a useful adjunct to treatment monitoring

Micafungin susceptibility of the most common<em> Candida</em> species in 16 French university hospitals : comparison between the Etest® and the EUCAST methods (MICACAND study)

International audienceObjectives : Micafungin is currently used in France. The aim of this study is to determine its activity against a recent (2014) French collection of Candida isolates. Although EUCAST is the reference method for in vitro antifungal susceptibility testing, it is not commonly used in routine clinical microbiology laboratories. Thus, it is important to evaluate alternative methods. We compared EUCAST and Etest for micafungin susceptibility testing of Candida spp. and we monitored the emergence of resistance. Methods: Sixteen centers (6 in Paris area and 10 across France) participated in a two-months prospective study. Clinical isolates of various Candida species (mainly C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, C. kefyr and C. krusei, about 10 isolates of each species per center) were tested by Etest, according to manufacturer’s instructions. All isolates were subsequently centralized in one center for MIC determination by EUCAST method. For comparison purposes, Etest MICs were raised to the next higher EUCAST concentration. Resistance was defined based on EUCAST clinical breakpoints or on epidemiological cut-off values when clinical breakpoints were not available. Results : A total number of 933 Candida isolates were tested. The overall agreement (+/- 2 log2 dilutions) between EUCAST and Etest was 97.9%. Species n E-Test EUCAST MIC range MIC range % agreement with Etest % resistance C. albicans 159 ≤ 0.015 - 0.06 ≤ 0.015 - 0.06 100 1.3 C. tropicalis 152 ≤ 0.015 - 0.5 ≤ 0.015 - 1 98.7 0.7 C. parapsilosis 152 ≤ 0.015 - 4 ≤ 0.125 - 4 96.1 1.3 C. glabrata 152 ≤ 0.015 - 0.125 ≤ 0.015 - 1 98.7 3.9 C. kefyr 136 ≤ 0.015 - 0.25 ≤ 0.015 - 0.125 97.8 ND C. krusei 127 ≤ 0.015 - 1 ≤ 0.015 - 0.25 96.9 0 Other Candida species* 55 ≤ 0.015 - 1 ≤ 0.015 - 1 94.5 ND Total 933 ≤ 0.015 - 4 ≤ 0.015 - 4 97.9 ND *: C. lusitaniae, C. guilliermondii, C. norvegensis, C. inconspicua, C. famata, C. pelliculosa, C. lambica, C. sphaerica, C. ciferii, C. catenulata, C. utilis, C. colliculosa, C. nivariensis Conclusions : This study demonstrated a very good agreement between Etest, performed on a routine basis, and EUCAST for micafungin MIC determination. Micafungin resistance among the main Candida species was uncommon

Multicenter comparison of the etest and EUCAST methods for antifungal susceptibility testing of Candida isolates to micafungin

International audienceIn vitro susceptibility of 933 Candida isolates, from 16 French hospitals, to micafungin was determined using the Etest in each center. All isolates were then sent to a single center for determination of MICs by the EUCAST reference method. Overall essential agreement between the two tests was 98.5% at ±2 log2 dilutions and 90.2% at ±1 log2 dilutions. Categorical agreement was 98.2%. The Etest is a valuable alternative to EUCAST for the routine determination of micafungin MICs in medical mycology laboratories. Copyright © 2016, American Society for Microbiology. All Rights Reserved